feat(stealth): mask identities and notify admins on login

build.gradle.kts

@@ -24,8 +24,10 @@ tasks.withType<JavaCompile>().configureEach {
 
 dependencies {
     compileOnly("org.spigotmc:spigot-api:26.2-R0.1-SNAPSHOT")
+    compileOnly("net.dmulloy2:ProtocolLib:5.4.0")
 
     testImplementation("org.spigotmc:spigot-api:26.2-R0.1-SNAPSHOT")
+    testImplementation("net.dmulloy2:ProtocolLib:5.4.0")
     testImplementation(platform("org.junit:junit-bom:5.13.4"))
     testImplementation("org.junit.jupiter:junit-jupiter")
     testImplementation("org.mockito:mockito-core:5.18.0")

design/index.md

@@ -4,7 +4,9 @@ okf_version: "0.1"
 
 # Spigot Stealth Design
 
-Spigot Stealth rewards players who spend time under invisibility effects from potions they drink, then lets unlocked players conceal their identity for a later session.
+Spigot Stealth rewards players who spend time under invisibility effects from potions they drink, then lets unlocked players conceal their identity for a later session. [Session concealment](user-stories/us-002-rejoin-without-visible-identity.md) includes command-suggestion filtering and scrambled message and overhead names.
+
+[Administration](user-stories/us-004-administer-player-stealth.md) provides private concealed-player counts at login and command-based inspection.
 
 ## Explore
 

design/log.md

@@ -1,7 +1,32 @@
 # Spigot Stealth Design Log
 
+## 2026-09-06
+
+- **Completion**: Extended US-004 with permission-gated private concealed-player counts for joining admins and arrival notices for online admins, including command hints, zero-count silence, and no duplicate notice for concealed admins. Verified all 70 tests, the JAR build, and OKF validation; not deployed or live-server tested.
+
+- **Completion**: Extended US-002 with concealed-username suggestion filtering, scrambled default chat and vanilla message/advancement names, scrambled overhead tags, and display-name restoration. Verified 65 automated tests, the Gradle JAR build, and OKF validation; live-server compatibility remains untested and custom chat/scoreboard integrations are outside this slice.
+
+## 2026-09-05
+
+- **Fix**: Reworked US-002 server-list filtering for Purpur's native `NameAndId` samples by filtering names through Bukkit, limiting ProtocolLib to guarded count adjustment, and rate-limiting compatibility warnings; verified the complete Gradle build and OKF bundle.
+- **Completion**: Extended US-002, US-004, and US-005 with a persistent, permission-gated sleep-count policy that excludes concealed players by default, applies immediately, restores prior player state, and supports contextual administration; verified the complete Gradle build and OKF bundle.
+- **Completion**: Extended US-002 with ProtocolLib filtering of concealed sessions from multiplayer server-list counts and player samples while preserving actual online state and advertised capacity; verified the complete Gradle build and OKF bundle.
+
+## 2026-09-04
+
+- **Completion**: Extended US-002 so concealed players disconnect without a public quit announcement while ordinary quit messages remain unchanged; verified listener tests, the complete Gradle build, and the OKF bundle.
+- **Completion**: Extended US-003 and US-004 with contextual, prefix-filtered command completion that suppresses generic player suggestions, plus an administrative list of all known online and offline unlocked players; verified the complete Gradle build and OKF bundle.
+
 ## 2026-08-14
 
+- **Completion**: Completed US-004 with exact known online and offline targeting, complete status, idempotent grants, confirmed resets, active concealment discovery, operator-default permissions, asynchronous persisted replies, and console audits; verified the full Gradle build.
+- **Implementation**: Began US-004 with test-first exact offline targeting, grant/reset transitions, concealed-player listing, permissions, confirmation, and audit logging.
+- **Completion**: Completed US-002 with single-use durable prepared logins, join-announcement suppression, ProtocolLib tab-only removal, scoreboard overhead-name suppression, visible physical entities, periodic observer refresh, respawn restoration, and disconnect or disable cleanup; verified the full Gradle build.
+- **Implementation**: Began US-002 with test-first prepared-login consumption, session-scoped concealment, join suppression, tab removal, and overhead-name presentation.
+- **Completion**: Completed US-003 with `/stealth progress`, live unsaved interval inclusion, configured target and remaining output, concise duration formatting, and unlocked usage guidance; verified the full Gradle build.
+- **Implementation**: Began US-003 with player-facing progress command and human-readable duration tests.
+- **Completion**: Completed US-001 with direct potion-drink effect attribution, monotonic elapsed-time accumulation, safe refresh and stop transitions, durable UUID progress, exact-once unlocking, and title plus chat presentation; verified the full Gradle build.
+- **Implementation**: Began US-001 with monotonic-clock progression tests and potion-cause event attribution.
 - **Completion**: Completed US-005 with validated eight-hour defaults and configurable messages, UUID-keyed immutable state, RFC 3339 timing metadata, safe invalid-record defaults, unknown-field preservation, atomic YAML replacement, periodic saves, and serialized off-thread persistence; verified the full Gradle build.
 - **Implementation**: Began US-005 with test-first validated settings, UUID-keyed state, and defensive asynchronous persistence.
 - **Completion**: Completed US-006 with a Java 17 Gradle build, strict compiler linting, Spigot API, JUnit 5, Mockito, plugin metadata, OKF validation, Gitea CI, conventional-commit checks, semantic releases, and versioned release assets; verified the full build and a `1.2.3` release JAR.

design/user-stories/index.md

@@ -1,8 +1,8 @@
 # Spigot Stealth User Stories
 
 1. [US-001: Accumulate invisibility time and unlock stealth](us-001-accumulate-invisibility-and-unlock.md) - Earn stealth by spending eight hours under invisibility effects from directly consumed potions.
-2. [US-002: Rejoin without a visible identity](us-002-rejoin-without-visible-identity.md) - Turn a qualifying invisible disconnect into one concealed online session.
+2. [US-002: Rejoin without a visible identity](us-002-rejoin-without-visible-identity.md) - Turn a qualifying invisible disconnect into one concealed online session with filtered name suggestions and scrambled message and overhead names.
 3. [US-003: Check personal stealth progress](us-003-check-personal-progress.md) - View accumulated time, remaining time, and unlock status.
-4. [US-004: Inspect and manage player stealth](us-004-administer-player-stealth.md) - Inspect and modify online or offline progression and find concealed players.
+4. [US-004: Inspect and manage player stealth](us-004-administer-player-stealth.md) - Inspect and modify online or offline progression, find concealed players, and receive private login count notices.
 5. [US-005: Configure and persist stealth progression](us-005-configure-and-persist-progression.md) - Keep progression durable and operator-configurable.
 6. [US-006: Build, test, and release the plugin](us-006-build-test-and-release.md) - Provide repeatable Gradle builds and Gitea delivery.

design/user-stories/us-001-accumulate-invisibility-and-unlock.md

@@ -2,7 +2,7 @@
 type: User Story
 title: "US-001: Accumulate invisibility time and unlock stealth"
 description: Reward sustained use of directly consumed invisibility potions with the stealth ability.
-status: backlog
+status: done
 ---
 
 # US-001: Accumulate invisibility time and unlock stealth
@@ -11,15 +11,19 @@ As a **player**, I want my qualifying invisibility time to accumulate so that su
 
 ## Acceptance criteria
 
-- [ ] Only time spent online under an invisibility effect produced by a potion the player directly drank contributes to progression.
-- [ ] Invisibility received from splash potions, lingering potions, tipped arrows, commands, plugins, or other sources does not contribute.
-- [ ] Qualifying time stops when the effect ends, is removed, is replaced by a non-qualifying source, the player disconnects, or the plugin disables.
-- [ ] Refreshed or overlapping qualifying effects never count elapsed time more than once.
-- [ ] Qualifying time accumulates across effects, sessions, and server restarts.
-- [ ] The ability unlocks when accumulated qualifying time reaches eight hours by default.
-- [ ] Reaching the threshold grants the unlock exactly once without discarding excess elapsed time.
-- [ ] When an online player unlocks stealth, they receive both a full-screen title and a chat message explaining the ability.
-- [ ] Progress and unlock ownership are associated with the player's UUID rather than their current name.
+- [x] Only time spent online under an invisibility effect produced by a potion the player directly drank contributes to progression.
+- [x] Invisibility received from splash potions, lingering potions, tipped arrows, commands, plugins, or other sources does not contribute.
+- [x] Qualifying time stops when the effect ends, is removed, is replaced by a non-qualifying source, the player disconnects, or the plugin disables.
+- [x] Refreshed or overlapping qualifying effects never count elapsed time more than once.
+- [x] Qualifying time accumulates across effects, sessions, and server restarts.
+- [x] The ability unlocks when accumulated qualifying time reaches eight hours by default.
+- [x] Reaching the threshold grants the unlock exactly once without discarding excess elapsed time.
+- [x] When an online player unlocks stealth, they receive both a full-screen title and a chat message explaining the ability.
+- [x] Progress and unlock ownership are associated with the player's UUID rather than their current name.
+
+## Validation
+
+Automated tests verify monotonic accumulation across intervals, refresh without duplicate time, exact-once threshold crossing with excess-time preservation, direct potion-drink cause filtering, non-qualifying replacement, UUID state, and online title and chat presentation. The complete `./gradlew clean check jar` lifecycle passes.
 
 ## Related
 

design/user-stories/us-002-rejoin-without-visible-identity.md

@@ -2,7 +2,7 @@
 type: User Story
 title: "US-002: Rejoin without a visible identity"
 description: Let an unlocked player turn a qualifying invisible disconnect into one identity-concealed session.
-status: backlog
+status: done
 ---
 
 # US-002: Rejoin without a visible identity
@@ -11,18 +11,49 @@ As an **unlocked player**, I want to disconnect while invisibility from a potion
 
 ## Acceptance criteria
 
-- [ ] An unlocked player becomes eligible for a concealed login only by disconnecting while an invisibility effect from a potion they directly drank remains active.
-- [ ] A player who has not unlocked stealth cannot prepare a concealed login.
-- [ ] An ordinary disconnect without an active qualifying effect clears any preparation for the next login.
-- [ ] On a prepared login, no public join announcement is shown.
-- [ ] Throughout the concealed session, the player is absent from every other player's tab list, including administrators' tab lists.
-- [ ] Throughout the concealed session, no overhead name tag identifies the player to any other player, including administrators.
-- [ ] The concealed player's physical character remains visible in the world and retains ordinary movement, interaction, combat, and permission behavior.
-- [ ] The concealed player receives a private message explaining that stealth is active for the session.
-- [ ] Concealment lasts until the player disconnects and is handled predictably across death and plugin reload or disable events.
-- [ ] Disconnecting consumes the current concealed session; another concealed login requires another qualifying potion and qualifying disconnect.
-- [ ] Merely owning the unlock never conceals an ordinary login or carries concealment automatically into a later session.
-- [ ] Prepared-login state survives a server restart between the qualifying disconnect and the next login.
+- [x] An unlocked player becomes eligible for a concealed login only by disconnecting while an invisibility effect from a potion they directly drank remains active.
+- [x] A player who has not unlocked stealth cannot prepare a concealed login.
+- [x] An ordinary disconnect without an active qualifying effect clears any preparation for the next login.
+- [x] On a prepared login, no public join announcement is shown.
+- [x] When a concealed player disconnects, no public quit or disconnect announcement is shown.
+- [x] Ordinary players' quit messages remain unchanged.
+- [x] Concealment is checked before disconnect cleanup so announcement suppression is reliable.
+- [x] Throughout the concealed session, the player is absent from every other player's tab list, including administrators' tab lists.
+- [x] The multiplayer server list's online-player count excludes currently concealed players.
+- [x] Concealed players are excluded from any player-name sample shown for the server-list count, while ordinary players remain represented.
+- [x] The public count never becomes negative, and the configured maximum-player count remains unchanged.
+- [x] Server-list concealment changes only the public ping response and does not alter actual online-player state or gameplay.
+- [x] Server-list filtering remains error-free when Purpur represents player samples with native `NameAndId` values rather than Mojang `GameProfile` values.
+- [x] A server-ping compatibility failure leaves the original response usable and does not produce repeated unhandled listener exceptions.
+- [x] By default, concealed players are excluded from sleep-percentage calculations.
+- [x] When the sleep-count policy is `include`, concealed players count normally; ordinary players are never modified by either policy.
+- [x] A player's previous sleeping-ignore state is restored when concealment ends, the player disconnects or is reset, the policy changes to `include`, or the plugin disables.
+- [x] Policy changes apply immediately to currently concealed players.
+- [x] Throughout the concealed session, the overhead name is rendered as scrambled magic text, including for administrators, while the physical character stays visible.
+- [x] Concealed usernames are excluded from outgoing command suggestions, including `/msg`, `/tell`, and `/w`; manually addressing a known username remains possible.
+- [x] Default chat display names and vanilla private-message and advancement name components are scrambled without changing message content or signed chat bodies.
+- [x] Masked message name components do not expose the original identity through hover or click actions.
+- [x] Previous display names and ordinary suggestions return when concealment ends; ordinary players remain unaffected.
+- [x] The concealed player's physical character remains visible in the world and retains ordinary movement, interaction, combat, and permission behavior.
+- [x] The concealed player receives a private message explaining that stealth is active for the session.
+- [x] Concealment lasts until the player disconnects and is handled predictably across death and plugin reload or disable events.
+- [x] Disconnecting consumes the current concealed session; another concealed login requires another qualifying potion and qualifying disconnect.
+- [x] Merely owning the unlock never conceals an ordinary login or carries concealment automatically into a later session.
+- [x] Prepared-login state survives a server restart between the qualifying disconnect and the next login.
+
+## Validation
+
+Automated tests verify unlocked and locked disconnect transitions, ordinary-disconnect clearing, one-login consumption, concealed join and quit announcement suppression, preservation of ordinary announcements, private activation messaging, ordinary-login presentation, tab removal for existing and new observers, overhead-name suppression, active concealed-session tracking, ProtocolLib-independent native player-sample filtering, guarded public server-list count adjustment, nonnegative counts, unchanged maximum capacity, default sleep-count exclusion, immediate policy changes, restoration of prior sleeping-ignore state, and the absence of entity-hiding calls. ProtocolLib is declared as a required dependency, prepared state round trips through YAML, and `./gradlew clean check jar` passes.
+
+Identity masking verification (2026-09-06): `./gradlew --offline clean check jar` passed all 65 tests and OKF validation. Tests cover semantic name slots, preserved message content, stripped identifying actions, reflected suggestion entries and chat-bound records, safe packet failure handling, immutable name snapshots, overhead formatting, and display-name restoration after repeated concealment. Presentation tests first failed to compile against the missing snapshot API, then passed after implementation. These are automated unit checks, not a live-client smoke test.
+
+## Identity masking scope
+
+Masking applies to active concealed sessions, not every potion effect. Outgoing username suggestions are filtered across commands; entering a known username manually still works. Default Bukkit chat uses a temporary scrambled `Anonymous` display name. Vanilla translated announcements and chat-type bound names are masked at the packet boundary without editing signed message bodies. The overhead tag uses scoreboard magic formatting on the profile name, not a profile rename; this is visual concealment, not anonymity against modified clients.
+
+Custom chat formats that ignore Bukkit display names, nicknames, custom scoreboards, and third-party messaging plugins may need dedicated integration. Unsupported packet layouts retain the original packet and emit one warning per packet type rather than interrupting chat delivery. Live-server/client compatibility still requires a smoke test, particularly after Minecraft or ProtocolLib upgrades.
+
+Implementation: [identity presentation](../../src/main/java/games/dmg/spigotstealth/BukkitIdentityPresentation.java), [packet listener](../../src/main/java/games/dmg/spigotstealth/ProtocolLibIdentityMaskingListener.java), and [semantic name masking](../../src/main/java/games/dmg/spigotstealth/StealthChatMasker.java).
 
 ## Related
 

design/user-stories/us-003-check-personal-progress.md

@@ -2,7 +2,7 @@
 type: User Story
 title: "US-003: Check personal stealth progress"
 description: Show a player their accumulated qualifying invisibility time and stealth unlock status.
-status: backlog
+status: done
 ---
 
 # US-003: Check personal stealth progress
@@ -11,13 +11,19 @@ As a **player**, I want to check my stealth progress so that I know how close I
 
 ## Acceptance criteria
 
-- [ ] `/stealth progress` reports the player's accumulated qualifying invisibility time.
-- [ ] Before unlock, the command reports the configured target and remaining duration.
-- [ ] While a qualifying effect is active, the report includes elapsed time not yet written during the current tracking interval.
-- [ ] After unlock, the command clearly reports that stealth is unlocked and explains how to prepare a concealed login.
-- [ ] Durations are presented in a concise, human-readable form.
-- [ ] Repeated command use does not change progression or concealment state.
-- [ ] The command has clear usage metadata and an appropriate player permission.
+- [x] `/stealth progress` reports the player's accumulated qualifying invisibility time.
+- [x] Before unlock, the command reports the configured target and remaining duration.
+- [x] While a qualifying effect is active, the report includes elapsed time not yet written during the current tracking interval.
+- [x] After unlock, the command clearly reports that stealth is unlocked and explains how to prepare a concealed login.
+- [x] Durations are presented in a concise, human-readable form.
+- [x] Repeated command use does not change progression or concealment state.
+- [x] The command has clear usage metadata and an appropriate player permission.
+- [x] `/stealth` tab-completes `progress`, filtered by the entered prefix.
+- [x] Unsupported argument positions return no suggestions instead of Bukkit's generic player list.
+
+## Validation
+
+Automated tests verify concise duration formatting, live in-flight progress, configured target and remaining output, command non-mutation, unlocked usage guidance, prefix-filtered completion, and suppression of irrelevant suggestions. Command metadata and the complete `./gradlew clean check jar` lifecycle pass.
 
 ## Related
 

design/user-stories/us-004-administer-player-stealth.md

@@ -2,7 +2,7 @@
 type: User Story
 title: "US-004: Inspect and manage player stealth"
 description: Give administrators durable controls for online and offline progression, unlocks, and active concealment.
-status: backlog
+status: done
 ---
 
 # US-004: Inspect and manage player stealth
@@ -11,19 +11,41 @@ As a **server administrator**, I want to inspect and correct player stealth stat
 
 ## Acceptance criteria
 
-- [ ] `/stealthadmin status <player|uuid>` reports accumulated time, unlock status, prepared-login state, and current concealment state.
-- [ ] Status inspection works for online players and known offline players selected by exact current or previously recorded name or UUID.
-- [ ] `/stealthadmin grant <player|uuid>` grants the unlock to an online or known offline player without altering accumulated time unnecessarily.
-- [ ] Granting an already-owned unlock is safe and clearly reports that no change was needed.
-- [ ] Granting the unlock sends the normal full-screen title and chat notification when the target is online.
-- [ ] `/stealthadmin reset <player|uuid> confirm` clears accumulated time, unlock ownership, prepared-login state, and current concealment for an online or known offline player.
-- [ ] Reset requires explicit confirmation and safely restores an online concealed player to ordinary identity presentation.
-- [ ] `/stealthadmin list` lists every currently online concealed player and clearly reports when there are none.
-- [ ] Concealed players remain absent from administrators' ordinary tab lists and retain hidden overhead name tags; the admin command is the supported discovery mechanism.
-- [ ] Commands clearly reject unknown, ambiguous, malformed, or otherwise invalid targets without creating unintended player records.
-- [ ] Administrative inspection and modification require an operator-default administrative permission.
-- [ ] State-changing operations persist before success is reported and are safe under retries.
-- [ ] Grant and reset actions record the administrator, target UUID, and action in the server log without blocking the server tick thread.
+- [x] `/stealthadmin status <player|uuid>` reports accumulated time, unlock status, prepared-login state, and current concealment state.
+- [x] Status inspection works for online players and known offline players selected by exact current or previously recorded name or UUID.
+- [x] `/stealthadmin grant <player|uuid>` grants the unlock to an online or known offline player without altering accumulated time unnecessarily.
+- [x] Granting an already-owned unlock is safe and clearly reports that no change was needed.
+- [x] Granting the unlock sends the normal full-screen title and chat notification when the target is online.
+- [x] `/stealthadmin reset <player|uuid> confirm` clears accumulated time, unlock ownership, prepared-login state, and current concealment for an online or known offline player.
+- [x] Reset requires explicit confirmation and safely restores an online concealed player to ordinary identity presentation.
+- [x] `/stealthadmin list` lists every currently online concealed player and clearly reports when there are none.
+- [x] Concealed players remain absent from administrators' ordinary tab lists and retain scrambled overhead names; the admin command is the supported discovery mechanism.
+- [x] An administrator joining while concealed players are online receives a private count and a hint to use `/stealthadmin list`.
+- [x] When a concealed player joins, online administrators receive a private arrival notice, the updated concealed-player count, and the command hint.
+- [x] Notifications require `spigotstealth.admin`; ordinary players receive no administrative notice.
+- [x] Counts include the newly joined concealed player, and a joining concealed administrator receives only one administrative notification.
+- [x] An administrator joining when no concealed players are online receives no notification.
+- [x] Commands clearly reject unknown, ambiguous, malformed, or otherwise invalid targets without creating unintended player records.
+- [x] Administrative inspection and modification require an operator-default administrative permission.
+- [x] State-changing operations persist before success is reported and are safe under retries.
+- [x] Grant and reset actions record the administrator, target UUID, and action in the server log without blocking the server tick thread.
+- [x] `/stealthadmin` tab-completes `status`, `grant`, `reset`, and `list`, filtered by the entered prefix.
+- [x] Target positions for `status`, `grant`, and `reset` suggest known player names, and reset's final argument suggests `confirm`.
+- [x] Administrative completions require the administrative permission, and irrelevant positions return no suggestions instead of Bukkit's generic player list.
+- [x] `/stealthadmin list unlocked` lists every known online or offline player with stealth unlocked.
+- [x] The unlocked list is sorted case-insensitively, identifies nameless records by UUID, and clearly reports when it is empty.
+- [x] Existing `/stealthadmin list` behavior continues to list currently concealed online players.
+- [x] `/stealthadmin sleepcount status` reports whether concealed players are included in or excluded from sleep-percentage calculations.
+- [x] `/stealthadmin sleepcount <include|exclude>` persists the policy before reporting success, applies it immediately, and records the administrator and policy in the server log.
+- [x] The `sleepcount`, `status`, `include`, and `exclude` arguments are permission-gated and contextually tab-completed.
+
+## Validation
+
+Automated tests verify exact offline name and UUID resolution, ambiguous and unknown rejection without record creation, complete status output, idempotent grants and notification, complete resets with presentation cleanup, online concealed-player filtering, online and offline unlocked-player listing, contextual permission-gated completion, durable sleep-count status and policy changes, immediate policy refresh, confirmation and permission gates, persisted-before-success replies, and audit records. The complete `./gradlew clean check jar` lifecycle passes.
+
+Login notice verification (2026-09-06): `./gradlew --offline clean check jar` passed all 70 tests and OKF validation. New tests first failed against the absent listener, then passed after implementation. Tests cover permission gates, zero-count silence, singular/plural counts, concealed-admin deduplication, ordinary-join silence for existing admins, and a prepared-login transition followed by an accurate administrative notice. Live-server verification remains pending.
+
+Implementation: [admin join listener](../../src/main/java/games/dmg/spigotstealth/StealthAdminJoinListener.java), registered at `MONITOR` after the session listener's `HIGHEST` login transition. Notices expose only counts; names remain available through `/stealthadmin list`.
 
 ## Related
 

design/user-stories/us-005-configure-and-persist-progression.md

@@ -23,10 +23,11 @@ As a **server operator**, I want stealth progression to be configurable and dura
 - [x] Corrupt, unknown, or invalid records cannot silently grant time, an unlock, a prepared login, or concealment.
 - [x] Unknown forward-compatible fields are preserved where practical.
 - [x] Persistence work does not perform blocking file operations on the server tick thread.
+- [x] The sleep-count policy persists in `state.yml` and defaults safely to `exclude` when missing or invalid.
 
 ## Validation
 
-Verified settings defaults and rejection, packaged configuration, safe UUID-state defaults, RFC 3339 round trips, unknown-field preservation, invalid-record rejection, atomic repository writes, and dedicated-thread loading and saving with automated tests and `./gradlew clean check jar`.
+Verified settings defaults and rejection, packaged configuration, safe UUID-state defaults, sleep-count policy defaults and round trips, RFC 3339 round trips, unknown-field preservation, invalid-record rejection, atomic repository writes, and dedicated-thread loading and saving with automated tests and `./gradlew clean check jar`.
 
 ## Related
 

src/main/java/games/dmg/spigotstealth/BukkitIdentityPresentation.java

@@ -0,0 +1,132 @@
+package games.dmg.spigotstealth;
+
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.UUID;
+import java.util.function.Supplier;
+import org.bukkit.entity.Player;
+import org.bukkit.scoreboard.Scoreboard;
+import org.bukkit.scoreboard.Team;
+
+/** Uses scoreboard metadata and tab-only packets while leaving player entities visible. */
+public final class BukkitIdentityPresentation implements IdentityPresentation {
+    private final Supplier<? extends Collection<? extends Player>> onlinePlayers;
+    private final Scoreboard scoreboard;
+    private final TabListController tabLists;
+    private final Supplier<SleepCountPolicy> sleepCountPolicy;
+    private final Map<UUID, Player> concealedPlayers = new LinkedHashMap<>();
+    private final Map<UUID, Boolean> previousSleepingIgnored = new LinkedHashMap<>();
+    private final Map<UUID, String> previousDisplayNames = new LinkedHashMap<>();
+    private volatile java.util.Set<String> concealedNames = java.util.Set.of();
+
+    /** Immutable snapshot safe to read from outgoing packet threads. */
+    public java.util.Set<String> concealedNames() {
+        return concealedNames;
+    }
+
+    private void publishNames() {
+        concealedNames = concealedPlayers.values().stream().map(Player::getName)
+                .collect(java.util.stream.Collectors.toUnmodifiableSet());
+    }
+
+    public BukkitIdentityPresentation(
+            Supplier<? extends Collection<? extends Player>> onlinePlayers,
+            Scoreboard scoreboard,
+            TabListController tabLists) {
+        this(onlinePlayers, scoreboard, tabLists, () -> SleepCountPolicy.EXCLUDE);
+    }
+
+    public BukkitIdentityPresentation(
+            Supplier<? extends Collection<? extends Player>> onlinePlayers,
+            Scoreboard scoreboard,
+            TabListController tabLists,
+            Supplier<SleepCountPolicy> sleepCountPolicy) {
+        this.onlinePlayers = Objects.requireNonNull(onlinePlayers, "onlinePlayers");
+        this.scoreboard = Objects.requireNonNull(scoreboard, "scoreboard");
+        this.tabLists = Objects.requireNonNull(tabLists, "tabLists");
+        this.sleepCountPolicy = Objects.requireNonNull(sleepCountPolicy, "sleepCountPolicy");
+    }
+
+    @Override
+    public void conceal(Player player) {
+        concealedPlayers.put(player.getUniqueId(), player);
+        publishNames();
+        previousDisplayNames.putIfAbsent(player.getUniqueId(), player.getDisplayName());
+        player.setDisplayName("§kAnonymous§r");
+        applySleepCountPolicy(player);
+        Team team = scoreboard.getTeam(teamName(player.getUniqueId()));
+        if (team == null) {
+            team = scoreboard.registerNewTeam(teamName(player.getUniqueId()));
+        }
+        team.setOption(Team.Option.NAME_TAG_VISIBILITY, Team.OptionStatus.ALWAYS);
+        team.setPrefix("§k");
+        team.setSuffix("§r");
+        team.addEntry(player.getName());
+        for (Player observer : onlinePlayers.get()) {
+            if (!observer.getUniqueId().equals(player.getUniqueId())) {
+                tabLists.remove(observer, player.getUniqueId());
+            }
+        }
+    }
+
+    @Override
+    public void reveal(Player player) {
+        boolean wasConcealed = concealedPlayers.remove(player.getUniqueId()) != null;
+        publishNames();
+        if (previousDisplayNames.containsKey(player.getUniqueId())) {
+            player.setDisplayName(previousDisplayNames.remove(player.getUniqueId()));
+        }
+        restoreSleepingIgnored(player);
+        Team team = scoreboard.getTeam(teamName(player.getUniqueId()));
+        if (team != null) {
+            wasConcealed = true;
+            team.removeEntry(player.getName());
+            team.unregister();
+        }
+        if (wasConcealed) {
+            for (Player observer : onlinePlayers.get()) {
+                if (!observer.getUniqueId().equals(player.getUniqueId())) {
+                    tabLists.add(observer, player);
+                }
+            }
+        }
+    }
+
+    @Override
+    public void refreshForObserver(Player observer) {
+        for (UUID concealedPlayerId : concealedPlayers.keySet()) {
+            if (!observer.getUniqueId().equals(concealedPlayerId)) {
+                tabLists.remove(observer, concealedPlayerId);
+            }
+        }
+    }
+
+    @Override
+    public void refreshSleepCountPolicy() {
+        for (Player player : concealedPlayers.values()) {
+            applySleepCountPolicy(player);
+        }
+    }
+
+    private void applySleepCountPolicy(Player player) {
+        if (sleepCountPolicy.get() == SleepCountPolicy.EXCLUDE) {
+            previousSleepingIgnored.computeIfAbsent(player.getUniqueId(), ignored -> player.isSleepingIgnored());
+            player.setSleepingIgnored(true);
+        } else {
+            restoreSleepingIgnored(player);
+        }
+    }
+
+    private void restoreSleepingIgnored(Player player) {
+        Boolean previous = previousSleepingIgnored.remove(player.getUniqueId());
+        if (previous != null) {
+            player.setSleepingIgnored(previous);
+        }
+    }
+
+    public static String teamName(UUID playerId) {
+        return "stlth" + playerId.toString().replace("-", "").substring(0, 11);
+    }
+}

src/main/java/games/dmg/spigotstealth/BukkitUnlockNotifier.java

@@ -0,0 +1,35 @@
+package games.dmg.spigotstealth;
+
+import java.util.Objects;
+import java.util.UUID;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import org.bukkit.entity.Player;
+
+/** Marshals unlock presentation onto the server thread. */
+public final class BukkitUnlockNotifier implements Consumer<UUID> {
+    private final Function<UUID, Player> playerLookup;
+    private final Consumer<Runnable> mainThread;
+    private final String chatMessage;
+
+    public BukkitUnlockNotifier(
+            Function<UUID, Player> playerLookup,
+            Consumer<Runnable> mainThread,
+            String chatMessage) {
+        this.playerLookup = Objects.requireNonNull(playerLookup, "playerLookup");
+        this.mainThread = Objects.requireNonNull(mainThread, "mainThread");
+        this.chatMessage = Objects.requireNonNull(chatMessage, "chatMessage");
+    }
+
+    @Override
+    public void accept(UUID playerId) {
+        mainThread.accept(() -> {
+            Player player = playerLookup.apply(playerId);
+            if (player == null || !player.isOnline()) {
+                return;
+            }
+            player.sendTitle("Stealth Unlocked", "Your identity can now be concealed", 10, 100, 20);
+            player.sendMessage(chatMessage);
+        });
+    }
+}

src/main/java/games/dmg/spigotstealth/IdentityPacketFields.java

@@ -0,0 +1,46 @@
+package games.dmg.spigotstealth;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+import java.lang.reflect.RecordComponent;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.UnaryOperator;
+
+/** Small reflective bridge: avoids a compile/runtime dependency on a specific NMS or Brigadier version. */
+final class IdentityPacketFields {
+    private IdentityPacketFields() { }
+
+    static List<?> filterEntries(List<?> entries, StealthChatMasker masker) throws ReflectiveOperationException {
+        List<Object> filtered = new ArrayList<>();
+        for (Object entry : entries) {
+            Method text;
+            try {
+                text = entry.getClass().getMethod("text");
+            } catch (NoSuchMethodException exception) {
+                text = entry.getClass().getMethod("getText");
+            }
+            if (!masker.isConcealedName((String) text.invoke(entry))) {
+                filtered.add(entry);
+            }
+        }
+        return List.copyOf(filtered);
+    }
+
+    static Object mapRecord(Object record, UnaryOperator<Object> mapper) throws ReflectiveOperationException {
+        RecordComponent[] components = record.getClass().getRecordComponents();
+        if (components == null) {
+            throw new IllegalArgumentException("Unsupported non-record chat binding");
+        }
+        Class<?>[] types = new Class<?>[components.length];
+        Object[] values = new Object[components.length];
+        for (int i = 0; i < components.length; i++) {
+            types[i] = components[i].getType();
+            Object value = components[i].getAccessor().invoke(record);
+            values[i] = value instanceof Optional<?> optional ? optional.map(mapper) : mapper.apply(value);
+        }
+        Constructor<?> constructor = record.getClass().getDeclaredConstructor(types);
+        return constructor.newInstance(values);
+    }
+}

src/main/java/games/dmg/spigotstealth/IdentityPresentation.java

@@ -0,0 +1,14 @@
+package games.dmg.spigotstealth;
+
+import org.bukkit.entity.Player;
+
+/** Presentation boundary that changes identity metadata without hiding the physical player entity. */
+public interface IdentityPresentation {
+    void conceal(Player player);
+
+    void reveal(Player player);
+
+    void refreshForObserver(Player observer);
+
+    void refreshSleepCountPolicy();
+}

src/main/java/games/dmg/spigotstealth/InvisibilityEffectListener.java

@@ -0,0 +1,52 @@
+package games.dmg.spigotstealth;
+
+import java.time.Clock;
+import java.time.Instant;
+import java.util.Objects;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.entity.EntityPotionEffectEvent;
+import org.bukkit.potion.PotionEffectType;
+
+/** Attributes invisibility changes to directly consumed potions and closes intervals safely. */
+public final class InvisibilityEffectListener implements Listener {
+    private final QualifyingInvisibilityService progression;
+    private final Clock clock;
+
+    public InvisibilityEffectListener(QualifyingInvisibilityService progression, Clock clock) {
+        this.progression = Objects.requireNonNull(progression, "progression");
+        this.clock = Objects.requireNonNull(clock, "clock");
+    }
+
+    @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
+    public void onPotionEffect(EntityPotionEffectEvent event) {
+        if (!(event.getEntity() instanceof Player player)) {
+            return;
+        }
+        handlePotionEffect(
+                player,
+                PotionEffectType.INVISIBILITY.equals(event.getModifiedType()),
+                event.getCause(),
+                event.getAction());
+    }
+
+    void handlePotionEffect(
+            Player player,
+            boolean invisibility,
+            EntityPotionEffectEvent.Cause cause,
+            EntityPotionEffectEvent.Action action) {
+        if (!invisibility) {
+            return;
+        }
+        boolean addedOrChanged = action == EntityPotionEffectEvent.Action.ADDED
+                || action == EntityPotionEffectEvent.Action.CHANGED;
+        if (cause == EntityPotionEffectEvent.Cause.POTION_DRINK && addedOrChanged) {
+            progression.begin(player.getUniqueId(), player.getName(), Instant.now(clock));
+        } else {
+            progression.stop(player.getUniqueId());
+        }
+    }
+
+}

src/main/java/games/dmg/spigotstealth/KnownPlayerResolver.java

@@ -0,0 +1,75 @@
+package games.dmg.spigotstealth;
+
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Objects;
+import java.util.UUID;
+import java.util.function.Supplier;
+import org.bukkit.entity.Player;
+
+/** Resolves only already-known UUIDs and exact names without creating offline-player records. */
+public final class KnownPlayerResolver {
+    private final Supplier<PersistentStealthState> state;
+    private final Supplier<? extends Collection<? extends Player>> onlinePlayers;
+
+    public KnownPlayerResolver(
+            Supplier<PersistentStealthState> state,
+            Supplier<? extends Collection<? extends Player>> onlinePlayers) {
+        this.state = Objects.requireNonNull(state, "state");
+        this.onlinePlayers = Objects.requireNonNull(onlinePlayers, "onlinePlayers");
+    }
+
+    public java.util.List<String> completeNames(String prefix) {
+        String normalized = prefix == null ? "" : prefix.toLowerCase(Locale.ROOT);
+        return knownPlayers().values().stream()
+                .map(KnownPlayer::name)
+                .filter(Objects::nonNull)
+                .distinct()
+                .filter(name -> name.toLowerCase(Locale.ROOT).startsWith(normalized))
+                .sorted(String.CASE_INSENSITIVE_ORDER)
+                .toList();
+    }
+
+    public Resolution resolve(String query) {
+        if (query == null || query.isBlank()) {
+            return new Resolution(Status.UNKNOWN, null);
+        }
+        Map<UUID, KnownPlayer> known = knownPlayers();
+        try {
+            UUID playerId = UUID.fromString(query);
+            KnownPlayer player = known.get(playerId);
+            return player == null ? new Resolution(Status.UNKNOWN, null) : new Resolution(Status.FOUND, player);
+        } catch (IllegalArgumentException ignored) {
+            // Continue with exact case-insensitive name resolution.
+        }
+        String normalized = query.toLowerCase(Locale.ROOT);
+        java.util.List<KnownPlayer> matches = known.values().stream()
+                .filter(player -> player.name() != null && player.name().toLowerCase(Locale.ROOT).equals(normalized))
+                .toList();
+        if (matches.isEmpty()) {
+            return new Resolution(Status.UNKNOWN, null);
+        }
+        if (matches.size() > 1) {
+            return new Resolution(Status.AMBIGUOUS, null);
+        }
+        return new Resolution(Status.FOUND, matches.get(0));
+    }
+
+    private Map<UUID, KnownPlayer> knownPlayers() {
+        Map<UUID, KnownPlayer> known = new LinkedHashMap<>();
+        state.get().players().forEach((playerId, playerState) ->
+                known.put(playerId, new KnownPlayer(playerId, playerState.lastKnownName(), null)));
+        for (Player player : onlinePlayers.get()) {
+            known.put(player.getUniqueId(), new KnownPlayer(player.getUniqueId(), player.getName(), player));
+        }
+        return known;
+    }
+
+    public enum Status { FOUND, UNKNOWN, AMBIGUOUS }
+
+    public record KnownPlayer(UUID playerId, String name, Player onlinePlayer) { }
+
+    public record Resolution(Status status, KnownPlayer player) { }
+}

src/main/java/games/dmg/spigotstealth/PersistentStealthState.java

@@ -8,12 +8,20 @@ import java.util.UUID;
 /** Immutable snapshot of all durable plugin state. */
 public record PersistentStealthState(
         Map<UUID, PlayerStealthState> players,
+        SleepCountPolicy sleepCountPolicy,
         Map<String, Object> unknownFields) {
     public PersistentStealthState {
         players = Map.copyOf(new LinkedHashMap<>(Objects.requireNonNull(players, "players")));
+        Objects.requireNonNull(sleepCountPolicy, "sleepCountPolicy");
         unknownFields = Map.copyOf(new LinkedHashMap<>(Objects.requireNonNull(unknownFields, "unknownFields")));
     }
 
+    public PersistentStealthState(
+            Map<UUID, PlayerStealthState> players,
+            Map<String, Object> unknownFields) {
+        this(players, SleepCountPolicy.EXCLUDE, unknownFields);
+    }
+
     public PlayerStealthState player(UUID playerId) {
         return players.getOrDefault(playerId, PlayerStealthState.empty(playerId));
     }
@@ -21,6 +29,10 @@ public record PersistentStealthState(
     public PersistentStealthState withPlayer(PlayerStealthState player) {
         Map<UUID, PlayerStealthState> updated = new LinkedHashMap<>(players);
         updated.put(player.playerId(), player);
-        return new PersistentStealthState(updated, unknownFields);
+        return new PersistentStealthState(updated, sleepCountPolicy, unknownFields);
+    }
+
+    public PersistentStealthState withSleepCountPolicy(SleepCountPolicy policy) {
+        return new PersistentStealthState(players, policy, unknownFields);
     }
 }

src/main/java/games/dmg/spigotstealth/ProtocolLibIdentityMaskingListener.java

@@ -0,0 +1,136 @@
+package games.dmg.spigotstealth;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.events.ListenerPriority;
+import com.comphenix.protocol.events.PacketAdapter;
+import com.comphenix.protocol.events.PacketContainer;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.reflect.StructureModifier;
+import com.comphenix.protocol.utility.MinecraftReflection;
+import com.comphenix.protocol.wrappers.WrappedChatComponent;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
+import org.bukkit.plugin.Plugin;
+
+/**
+ * Outgoing identity-only masking. Registration is deliberately left to the plugin.
+ * The supplier must return an immutable, safely published snapshot (for example AtomicReference::get).
+ * It must not inspect Bukkit players or mutable session collections on the packet thread.
+ */
+public final class ProtocolLibIdentityMaskingListener extends PacketAdapter {
+    private final Supplier<Set<String>> concealedNames;
+    private final Consumer<String> warningLog;
+    private final Set<PacketType> warned = ConcurrentHashMap.newKeySet();
+
+    public ProtocolLibIdentityMaskingListener(
+            Plugin plugin, Supplier<Set<String>> concealedNames, Consumer<String> warningLog) {
+        // ProtocolLib calls the vanilla PLAYER_CHAT packet CHAT.
+        super(plugin, ListenerPriority.HIGHEST, PacketType.Play.Server.TAB_COMPLETE,
+                PacketType.Play.Server.SYSTEM_CHAT, PacketType.Play.Server.CHAT,
+                PacketType.Play.Server.DISGUISED_CHAT);
+        this.concealedNames = Objects.requireNonNull(concealedNames, "concealedNames");
+        this.warningLog = Objects.requireNonNull(warningLog, "warningLog");
+    }
+
+    @Override
+    public void onPacketSending(PacketEvent event) {
+        if (event.isCancelled()) {
+            return;
+        }
+        try {
+            Set<String> snapshot = concealedNames.get();
+            if (snapshot.isEmpty()) {
+                return;
+            }
+            StealthChatMasker masker = new StealthChatMasker(snapshot);
+            PacketContainer packet = event.getPacket().shallowClone();
+            if (event.getPacketType().equals(PacketType.Play.Server.TAB_COMPLETE)) {
+                filterSuggestions(packet, masker);
+            } else if (event.getPacketType().equals(PacketType.Play.Server.SYSTEM_CHAT)) {
+                maskSystemChat(packet, masker);
+            } else {
+                maskBoundNames(packet, masker);
+            }
+            event.setPacket(packet);
+        } catch (ReflectiveOperationException | RuntimeException exception) {
+            // Keep delivery usable; do not cancel signed chat and break the acknowledgement chain.
+            if (warned.add(event.getPacketType())) {
+                warningLog.accept("Stealth identity masking unavailable for " + event.getPacketType()
+                        + "; original packet retained. Failure: " + exception.getClass().getSimpleName());
+            }
+        }
+    }
+
+    private static void filterSuggestions(PacketContainer packet, StealthChatMasker masker)
+            throws ReflectiveOperationException {
+        StructureModifier<Object> fields = packet.getModifier();
+        for (int i = 0; i < fields.size(); i++) {
+            Object value = fields.read(i);
+            if (value instanceof List<?> entries) {
+                // Modern ClientboundCommandSuggestionsPacket stores its Entry list directly.
+                fields.write(i, IdentityPacketFields.filterEntries(entries, masker));
+                return;
+            }
+            if (value != null && value.getClass().getName().equals("com.mojang.brigadier.suggestion.Suggestions")) {
+                Object range = value.getClass().getMethod("getRange").invoke(value);
+                List<?> entries = (List<?>) value.getClass().getMethod("getList").invoke(value);
+                List<?> filtered = IdentityPacketFields.filterEntries(entries, masker);
+                fields.write(i, value.getClass().getConstructor(range.getClass(), List.class).newInstance(range, filtered));
+                return;
+            }
+        }
+        // Pre-Brigadier protocol compatibility.
+        StructureModifier<String[]> arrays = packet.getStringArrays();
+        if (arrays.size() > 0) {
+            arrays.write(0, java.util.Arrays.stream(arrays.read(0))
+                    .filter(name -> !masker.isConcealedName(name)).toArray(String[]::new));
+            return;
+        }
+        throw new IllegalStateException("Unsupported command suggestions layout");
+    }
+
+    private static void maskSystemChat(PacketContainer packet, StealthChatMasker masker) {
+        StructureModifier<WrappedChatComponent> components = packet.getChatComponents();
+        if (components.size() > 0) {
+            WrappedChatComponent original = components.read(0);
+            String json = original.getJson();
+            String masked = masker.maskAnnouncement(json);
+            if (!json.equals(masked)) {
+                components.write(0, WrappedChatComponent.fromJson(masked));
+            }
+        } else if (packet.getStrings().size() > 0) {
+            // Older SYSTEM_CHAT represents its component as JSON text.
+            String json = packet.getStrings().read(0);
+            packet.getStrings().write(0, masker.maskAnnouncement(json));
+        } else {
+            throw new IllegalStateException("Unsupported system chat layout");
+        }
+    }
+
+    private static void maskBoundNames(PacketContainer packet, StealthChatMasker masker)
+            throws ReflectiveOperationException {
+        StructureModifier<Object> fields = packet.getModifier();
+        for (int i = 0; i < fields.size(); i++) {
+            Object value = fields.read(i);
+            if (value != null && (value.getClass().getName().endsWith("ChatType$BoundNetwork")
+                    || value.getClass().getName().endsWith("ChatType$Bound"))) {
+                Object masked = IdentityPacketFields.mapRecord(value, field -> {
+                    if (field != null && MinecraftReflection.getIChatBaseComponentClass().isInstance(field)) {
+                        String json = WrappedChatComponent.fromHandle(field).getJson();
+                        String replacement = masker.maskDisplayName(json);
+                        return json.equals(replacement) ? field : WrappedChatComponent.fromJson(replacement).getHandle();
+                    }
+                    return field;
+                });
+                fields.write(i, masked);
+                return;
+            }
+        }
+        // Intentionally never touch signed body, unsigned body, UUID, signature, or filter mask.
+        throw new IllegalStateException("Unsupported player chat display-name layout");
+    }
+}

src/main/java/games/dmg/spigotstealth/ProtocolLibServerListPingListener.java

@@ -0,0 +1,37 @@
+package games.dmg.spigotstealth;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.events.PacketAdapter;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.wrappers.WrappedServerPing;
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
+import org.bukkit.plugin.Plugin;
+
+/** Adjusts only the count in outgoing server-list responses through ProtocolLib. */
+public final class ProtocolLibServerListPingListener extends PacketAdapter {
+    private final Supplier<Set<UUID>> concealedPlayerIds;
+    private final ServerPingCompatibilityGuard compatibilityGuard;
+
+    public ProtocolLibServerListPingListener(
+            Plugin plugin,
+            Supplier<Set<UUID>> concealedPlayerIds,
+            Consumer<String> warningLog) {
+        super(plugin, PacketType.Status.Server.SERVER_INFO);
+        this.concealedPlayerIds = Objects.requireNonNull(concealedPlayerIds, "concealedPlayerIds");
+        this.compatibilityGuard = new ServerPingCompatibilityGuard(warningLog);
+    }
+
+    @Override
+    public void onPacketSending(PacketEvent event) {
+        compatibilityGuard.run(() -> {
+            WrappedServerPing ping = event.getPacket().getServerPings().read(0);
+            int visiblePlayers = ServerListPingVisibility.visibleOnlineCount(
+                    ping.getPlayersOnline(), concealedPlayerIds.get().size());
+            ping.setPlayersOnline(visiblePlayers);
+        });
+    }
+}

src/main/java/games/dmg/spigotstealth/ProtocolLibTabListController.java

@@ -0,0 +1,52 @@
+package games.dmg.spigotstealth;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.events.PacketContainer;
+import com.comphenix.protocol.wrappers.EnumWrappers;
+import com.comphenix.protocol.wrappers.PlayerInfoData;
+import com.comphenix.protocol.wrappers.WrappedChatComponent;
+import com.comphenix.protocol.wrappers.WrappedGameProfile;
+import com.comphenix.protocol.wrappers.WrappedRemoteChatSessionData;
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.UUID;
+import org.bukkit.entity.Player;
+
+/** ProtocolLib adapter for tab-list-only removal and restoration packets. */
+public final class ProtocolLibTabListController implements TabListController {
+    private final ProtocolManager protocolManager;
+
+    public ProtocolLibTabListController(ProtocolManager protocolManager) {
+        this.protocolManager = Objects.requireNonNull(protocolManager, "protocolManager");
+    }
+
+    @Override
+    public void remove(Player observer, UUID targetPlayerId) {
+        PacketContainer packet = protocolManager.createPacket(PacketType.Play.Server.PLAYER_INFO_REMOVE);
+        packet.getUUIDLists().write(0, List.of(targetPlayerId));
+        protocolManager.sendServerPacket(observer, packet);
+    }
+
+    @Override
+    public void add(Player observer, Player target) {
+        PacketContainer packet = protocolManager.createPacket(PacketType.Play.Server.PLAYER_INFO);
+        packet.getPlayerInfoActions().write(0, EnumSet.of(
+                EnumWrappers.PlayerInfoAction.ADD_PLAYER,
+                EnumWrappers.PlayerInfoAction.UPDATE_GAME_MODE,
+                EnumWrappers.PlayerInfoAction.UPDATE_LISTED,
+                EnumWrappers.PlayerInfoAction.UPDATE_LATENCY,
+                EnumWrappers.PlayerInfoAction.UPDATE_DISPLAY_NAME));
+        PlayerInfoData data = new PlayerInfoData(
+                target.getUniqueId(),
+                target.getPing(),
+                true,
+                EnumWrappers.NativeGameMode.fromBukkit(target.getGameMode()),
+                WrappedGameProfile.fromPlayer(target),
+                WrappedChatComponent.fromText(target.getPlayerListName()),
+                (WrappedRemoteChatSessionData) null);
+        packet.getPlayerInfoDataLists().write(1, List.of(data));
+        protocolManager.sendServerPacket(observer, packet);
+    }
+}

src/main/java/games/dmg/spigotstealth/QualifyingInvisibilityService.java

@@ -0,0 +1,122 @@
+package games.dmg.spigotstealth;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Consumer;
+import java.util.function.LongSupplier;
+
+/** Accumulates qualifying potion invisibility using monotonic elapsed time. */
+public final class QualifyingInvisibilityService {
+    private final StealthStateManager stateManager;
+    private final long unlockThresholdMillis;
+    private final LongSupplier nanoTime;
+    private final Consumer<UUID> unlockNotifier;
+    private final Map<UUID, ActiveInterval> activeIntervals = new HashMap<>();
+
+    public QualifyingInvisibilityService(
+            StealthStateManager stateManager,
+            Duration unlockThreshold,
+            LongSupplier nanoTime,
+            Consumer<UUID> unlockNotifier) {
+        this.stateManager = Objects.requireNonNull(stateManager, "stateManager");
+        this.unlockThresholdMillis = Objects.requireNonNull(unlockThreshold, "unlockThreshold").toMillis();
+        this.nanoTime = Objects.requireNonNull(nanoTime, "nanoTime");
+        this.unlockNotifier = Objects.requireNonNull(unlockNotifier, "unlockNotifier");
+    }
+
+    public CompletableFuture<Void> begin(UUID playerId, String playerName, Instant startedAt) {
+        Objects.requireNonNull(playerId, "playerId");
+        Objects.requireNonNull(startedAt, "startedAt");
+        long nowNanos = nanoTime.getAsLong();
+        ActiveInterval previous = activeIntervals.put(playerId, new ActiveInterval(nowNanos, startedAt, playerName));
+        return record(playerId, playerName, elapsedMillis(previous, nowNanos), startedAt, true);
+    }
+
+    public CompletableFuture<Void> checkpoint(UUID playerId) {
+        long nowNanos = nanoTime.getAsLong();
+        ActiveInterval previous = activeIntervals.get(playerId);
+        if (previous == null) {
+            return CompletableFuture.completedFuture(null);
+        }
+        long elapsedMillis = elapsedMillis(previous, nowNanos);
+        Instant continuedAt = previous.startedAt().plusMillis(elapsedMillis);
+        activeIntervals.put(playerId, new ActiveInterval(nowNanos, continuedAt, previous.playerName()));
+        return record(playerId, previous.playerName(), elapsedMillis, continuedAt, true);
+    }
+
+    public CompletableFuture<Void> stop(UUID playerId) {
+        long nowNanos = nanoTime.getAsLong();
+        ActiveInterval previous = activeIntervals.remove(playerId);
+        if (previous == null) {
+            return CompletableFuture.completedFuture(null);
+        }
+        return record(playerId, previous.playerName(), elapsedMillis(previous, nowNanos), null, false);
+    }
+
+    public boolean isQualifying(UUID playerId) {
+        return activeIntervals.containsKey(playerId);
+    }
+
+    public Set<UUID> activePlayerIds() {
+        return Set.copyOf(activeIntervals.keySet());
+    }
+
+    public CompletableFuture<Void> stopAll() {
+        CompletableFuture<?>[] stops = activePlayerIds().stream()
+                .map(this::stop)
+                .toArray(CompletableFuture[]::new);
+        return CompletableFuture.allOf(stops);
+    }
+
+    public long currentAccumulatedMillis(UUID playerId) {
+        long persisted = stateManager.snapshot().player(playerId).accumulatedMillis();
+        return Math.addExact(persisted, elapsedMillis(activeIntervals.get(playerId), nanoTime.getAsLong()));
+    }
+
+    private CompletableFuture<Void> record(
+            UUID playerId,
+            String playerName,
+            long elapsedMillis,
+            Instant qualifyingSince,
+            boolean active) {
+        AtomicBoolean unlockedNow = new AtomicBoolean();
+        CompletableFuture<Void> saved = stateManager.update(state -> {
+            PlayerStealthState player = state.player(playerId);
+            long accumulated = Math.addExact(player.accumulatedMillis(), elapsedMillis);
+            boolean unlocked = player.unlocked() || accumulated >= unlockThresholdMillis;
+            unlockedNow.set(unlocked && !player.unlocked());
+            PlayerStealthState updated = new PlayerStealthState(
+                    playerId,
+                    playerName,
+                    accumulated,
+                    unlocked,
+                    player.preparedLogin(),
+                    player.concealed(),
+                    active ? qualifyingSince : null,
+                    player.unknownFields());
+            return state.withPlayer(updated);
+        });
+        return saved.thenRun(() -> {
+            if (unlockedNow.get()) {
+                unlockNotifier.accept(playerId);
+            }
+        });
+    }
+
+    private static long elapsedMillis(ActiveInterval interval, long nowNanos) {
+        if (interval == null) {
+            return 0L;
+        }
+        long elapsedNanos = Math.max(0L, nowNanos - interval.startedNanos());
+        return Duration.ofNanos(elapsedNanos).toMillis();
+    }
+
+    private record ActiveInterval(long startedNanos, Instant startedAt, String playerName) { }
+}

src/main/java/games/dmg/spigotstealth/ServerListPingListener.java

@@ -0,0 +1,32 @@
+package games.dmg.spigotstealth;
+
+import java.util.Iterator;
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+import java.util.function.Supplier;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.server.ServerListPingEvent;
+
+/** Filters concealed players through Bukkit's native server-list sample representation. */
+public final class ServerListPingListener implements Listener {
+    private final Supplier<Set<UUID>> concealedPlayerIds;
+
+    public ServerListPingListener(Supplier<Set<UUID>> concealedPlayerIds) {
+        this.concealedPlayerIds = Objects.requireNonNull(concealedPlayerIds, "concealedPlayerIds");
+    }
+
+    @EventHandler(priority = EventPriority.HIGHEST)
+    public void onServerListPing(ServerListPingEvent event) {
+        Set<UUID> concealed = concealedPlayerIds.get();
+        Iterator<Player> sample = event.iterator();
+        while (sample.hasNext()) {
+            if (concealed.contains(sample.next().getUniqueId())) {
+                sample.remove();
+            }
+        }
+    }
+}

src/main/java/games/dmg/spigotstealth/ServerListPingVisibility.java

@@ -0,0 +1,37 @@
+package games.dmg.spigotstealth;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+
+/** Computes the public multiplayer server-list view for concealed sessions. */
+public final class ServerListPingVisibility {
+    private ServerListPingVisibility() { }
+
+    public static Snapshot adjust(
+            int playersOnline,
+            int playersMaximum,
+            List<UUID> samplePlayerIds,
+            Set<UUID> concealedPlayerIds) {
+        Objects.requireNonNull(samplePlayerIds, "samplePlayerIds");
+        Objects.requireNonNull(concealedPlayerIds, "concealedPlayerIds");
+        List<UUID> visibleSample = samplePlayerIds.stream()
+                .filter(playerId -> !concealedPlayerIds.contains(playerId))
+                .toList();
+        return new Snapshot(
+                visibleOnlineCount(playersOnline, concealedPlayerIds.size()),
+                playersMaximum,
+                visibleSample);
+    }
+
+    public static int visibleOnlineCount(int playersOnline, int concealedPlayers) {
+        return Math.max(0, playersOnline - concealedPlayers);
+    }
+
+    public record Snapshot(int playersOnline, int playersMaximum, List<UUID> samplePlayerIds) {
+        public Snapshot {
+            samplePlayerIds = List.copyOf(samplePlayerIds);
+        }
+    }
+}

src/main/java/games/dmg/spigotstealth/ServerPingCompatibilityGuard.java

@@ -0,0 +1,26 @@
+package games.dmg.spigotstealth;
+
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Consumer;
+
+/** Keeps an incompatible server-ping adapter from breaking responses or flooding logs. */
+public final class ServerPingCompatibilityGuard {
+    private final Consumer<String> warningLog;
+    private final AtomicBoolean warningLogged = new AtomicBoolean();
+
+    public ServerPingCompatibilityGuard(Consumer<String> warningLog) {
+        this.warningLog = Objects.requireNonNull(warningLog, "warningLog");
+    }
+
+    public void run(Runnable edit) {
+        try {
+            edit.run();
+        } catch (RuntimeException exception) {
+            if (warningLogged.compareAndSet(false, true)) {
+                warningLog.accept("Unable to adjust the public server-list player count; "
+                        + "the original response will be used: " + exception.getMessage());
+            }
+        }
+    }
+}

src/main/java/games/dmg/spigotstealth/SleepCountPolicy.java

@@ -0,0 +1,24 @@
+package games.dmg.spigotstealth;
+
+import java.util.Locale;
+
+/** Whether concealed players participate in the server's sleep percentage. */
+public enum SleepCountPolicy {
+    INCLUDE,
+    EXCLUDE;
+
+    public static SleepCountPolicy fromPersisted(Object value) {
+        if (value instanceof String text) {
+            try {
+                return valueOf(text.toUpperCase(Locale.ROOT));
+            } catch (IllegalArgumentException ignored) {
+                // Invalid values use the privacy-preserving default.
+            }
+        }
+        return EXCLUDE;
+    }
+
+    public String persistedValue() {
+        return name().toLowerCase(Locale.ROOT);
+    }
+}

src/main/java/games/dmg/spigotstealth/SpigotStealthPlugin.java

@@ -1,6 +1,10 @@
 package games.dmg.spigotstealth;
 
+import com.comphenix.protocol.ProtocolLibrary;
+import com.comphenix.protocol.ProtocolManager;
 import java.nio.file.Path;
+import java.time.Clock;
+import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionException;
 import org.bukkit.plugin.java.JavaPlugin;
@@ -9,6 +13,10 @@ import org.bukkit.plugin.java.JavaPlugin;
 public final class SpigotStealthPlugin extends JavaPlugin {
     private CompletableFuture<StealthStateManager> stateManagerFuture;
     private StealthSettings settings;
+    private QualifyingInvisibilityService progression;
+    private StealthSessionService sessions;
+    private IdentityPresentation identityPresentation;
+    private ProtocolManager protocolManager;
 
     @Override
     public void onEnable() {
@@ -35,6 +43,20 @@ public final class SpigotStealthPlugin extends JavaPlugin {
 
     @Override
     public void onDisable() {
+        if (protocolManager != null) {
+            protocolManager.removePacketListeners(this);
+        }
+        if (identityPresentation != null && sessions != null) {
+            for (org.bukkit.entity.Player player : getServer().getOnlinePlayers()) {
+                if (sessions.isConcealed(player.getUniqueId())) {
+                    identityPresentation.reveal(player);
+                    sessions.endConcealment(player.getUniqueId());
+                }
+            }
+        }
+        if (progression != null) {
+            progression.stopAll().join();
+        }
         if (stateManagerFuture != null && stateManagerFuture.isDone() && !stateManagerFuture.isCompletedExceptionally()) {
             stateManagerFuture.join().close();
         }
@@ -45,11 +67,71 @@ public final class SpigotStealthPlugin extends JavaPlugin {
     }
 
     private void finishInitialization(StealthStateManager manager) {
-        getServer().getScheduler().runTaskTimer(this, ignored -> manager.save().exceptionally(failure -> {
+        java.util.function.Consumer<Runnable> mainThread =
+                runnable -> getServer().getScheduler().runTask(this, runnable);
+        BukkitUnlockNotifier notifier = new BukkitUnlockNotifier(
+                getServer()::getPlayer,
+                mainThread,
+                settings.unlockedMessage());
+        progression = new QualifyingInvisibilityService(
+                manager, settings.unlockThreshold(), System::nanoTime, notifier);
+        sessions = new StealthSessionService(manager, progression);
+        protocolManager = ProtocolLibrary.getProtocolManager();
+        BukkitIdentityPresentation bukkitPresentation = new BukkitIdentityPresentation(
+                getServer()::getOnlinePlayers,
+                Objects.requireNonNull(getServer().getScoreboardManager(), "scoreboard manager").getMainScoreboard(),
+                new ProtocolLibTabListController(protocolManager),
+                () -> manager.snapshot().sleepCountPolicy());
+        identityPresentation = bukkitPresentation;
+        protocolManager.addPacketListener(new ProtocolLibIdentityMaskingListener(
+                this, bukkitPresentation::concealedNames, getLogger()::warning));
+        protocolManager.addPacketListener(new ProtocolLibServerListPingListener(
+                this, sessions::concealedPlayerIds, getLogger()::warning));
+        getServer().getPluginManager().registerEvents(
+                new ServerListPingListener(sessions::concealedPlayerIds), this);
+        getServer().getPluginManager().registerEvents(
+                new InvisibilityEffectListener(progression, Clock.systemUTC()), this);
+        getServer().getPluginManager().registerEvents(
+                new StealthSessionListener(sessions, identityPresentation, settings.concealedMessage()), this);
+        getServer().getPluginManager().registerEvents(
+                new StealthAdminJoinListener(sessions, getServer()::getOnlinePlayers), this);
+        org.bukkit.command.PluginCommand stealthPluginCommand =
+                Objects.requireNonNull(getCommand("stealth"), "stealth command");
+        StealthCommand stealthCommand = new StealthCommand(manager, progression, settings);
+        stealthPluginCommand.setExecutor(stealthCommand);
+        stealthPluginCommand.setTabCompleter(stealthCommand);
+        StealthAdministrationService administration = new StealthAdministrationService(
+                manager, progression, identityPresentation, notifier, getServer()::getOnlinePlayers);
+        KnownPlayerResolver resolver = new KnownPlayerResolver(manager::snapshot, getServer()::getOnlinePlayers);
+        org.bukkit.command.PluginCommand stealthAdminPluginCommand =
+                Objects.requireNonNull(getCommand("stealthadmin"), "stealthadmin command");
+        StealthAdminCommand stealthAdminCommand = new StealthAdminCommand(
+                administration,
+                resolver,
+                mainThread,
+                getLogger()::info,
+                settings.unlockThreshold());
+        stealthAdminPluginCommand.setExecutor(stealthAdminCommand);
+        stealthAdminPluginCommand.setTabCompleter(stealthAdminCommand);
+        getServer().getScheduler().runTaskTimer(this, ignored -> {
+            for (java.util.UUID playerId : progression.activePlayerIds()) {
+                logSaveFailure(progression.checkpoint(playerId));
+            }
+        }, 20L, 20L);
+        getServer().getScheduler().runTaskTimer(this, ignored -> {
+            for (org.bukkit.entity.Player observer : getServer().getOnlinePlayers()) {
+                identityPresentation.refreshForObserver(observer);
+            }
+        }, 20L, 20L);
+        getServer().getScheduler().runTaskTimer(this, ignored -> logSaveFailure(manager.save()), 6000L, 6000L);
+        getLogger().info("Spigot Stealth enabled");
+    }
+
+    private void logSaveFailure(CompletableFuture<Void> save) {
+        save.exceptionally(failure -> {
             getLogger().severe("Unable to save Spigot Stealth state: " + rootMessage(failure));
             return null;
-        }), 6000L, 6000L);
-        getLogger().info("Spigot Stealth enabled");
+        });
     }
 
     private static String rootMessage(Throwable throwable) {

src/main/java/games/dmg/spigotstealth/StealthAdminCommand.java

@@ -0,0 +1,224 @@
+package games.dmg.spigotstealth;
+
+import java.time.Duration;
+import java.util.List;
+import java.util.Locale;
+import java.util.Objects;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Consumer;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabCompleter;
+
+/** Permission-gated administrative command for online and known offline players. */
+public final class StealthAdminCommand implements CommandExecutor, TabCompleter {
+    private static final String PERMISSION = "spigotstealth.admin";
+    private static final List<String> OPERATIONS = List.of("status", "grant", "reset", "list", "sleepcount");
+    private final StealthAdministrationService administration;
+    private final KnownPlayerResolver resolver;
+    private final Consumer<Runnable> mainThread;
+    private final Consumer<String> auditLog;
+    private final Duration unlockThreshold;
+
+    public StealthAdminCommand(
+            StealthAdministrationService administration,
+            KnownPlayerResolver resolver,
+            Consumer<Runnable> mainThread,
+            Consumer<String> auditLog,
+            Duration unlockThreshold) {
+        this.administration = Objects.requireNonNull(administration, "administration");
+        this.resolver = Objects.requireNonNull(resolver, "resolver");
+        this.mainThread = Objects.requireNonNull(mainThread, "mainThread");
+        this.auditLog = Objects.requireNonNull(auditLog, "auditLog");
+        this.unlockThreshold = Objects.requireNonNull(unlockThreshold, "unlockThreshold");
+    }
+
+    @Override
+    public List<String> onTabComplete(
+            CommandSender sender, Command command, String label, String[] arguments) {
+        if (!sender.hasPermission(PERMISSION)) {
+            return List.of();
+        }
+        if (arguments.length == 1) {
+            return matching(OPERATIONS, arguments[0]);
+        }
+        String operation = arguments[0].toLowerCase(Locale.ROOT);
+        if (arguments.length == 2) {
+            if (List.of("status", "grant", "reset").contains(operation)) {
+                return resolver.completeNames(arguments[1]);
+            }
+            if ("list".equals(operation)) {
+                return matching(List.of("unlocked"), arguments[1]);
+            }
+            if ("sleepcount".equals(operation)) {
+                return matching(List.of("status", "include", "exclude"), arguments[1]);
+            }
+        }
+        if (arguments.length == 3 && "reset".equals(operation)) {
+            return matching(List.of("confirm"), arguments[2]);
+        }
+        return List.of();
+    }
+
+    private static List<String> matching(List<String> candidates, String prefix) {
+        String normalized = prefix.toLowerCase(Locale.ROOT);
+        return candidates.stream().filter(candidate -> candidate.startsWith(normalized)).toList();
+    }
+
+    @Override
+    public boolean onCommand(CommandSender sender, Command command, String label, String[] arguments) {
+        if (!sender.hasPermission(PERMISSION)) {
+            sender.sendMessage("You do not have permission to administer Spigot Stealth.");
+            return true;
+        }
+        if (arguments.length > 0 && "sleepcount".equalsIgnoreCase(arguments[0])) {
+            return sleepCount(sender, label, arguments);
+        }
+        if (arguments.length > 0 && "list".equalsIgnoreCase(arguments[0])) {
+            if (arguments.length == 1) {
+                List<String> names = administration.concealedOnlineNames();
+                sender.sendMessage(names.isEmpty()
+                        ? "No players are currently concealed."
+                        : "Currently concealed: " + String.join(", ", names));
+                return true;
+            }
+            if (arguments.length == 2 && "unlocked".equalsIgnoreCase(arguments[1])) {
+                List<String> names = administration.unlockedPlayerNames();
+                sender.sendMessage(names.isEmpty()
+                        ? "No players have unlocked stealth."
+                        : "Stealth unlocked: " + String.join(", ", names));
+                return true;
+            }
+            sendUsage(sender, label);
+            return true;
+        }
+        if (arguments.length < 2) {
+            sendUsage(sender, label);
+            return true;
+        }
+        String operation = arguments[0].toLowerCase(Locale.ROOT);
+        KnownPlayerResolver.Resolution resolution = resolver.resolve(arguments[1]);
+        if (resolution.status() != KnownPlayerResolver.Status.FOUND) {
+            sender.sendMessage(resolution.status() == KnownPlayerResolver.Status.AMBIGUOUS
+                    ? "That player name is ambiguous; use a UUID."
+                    : "Unknown player. Use an exact known name or UUID.");
+            return true;
+        }
+        KnownPlayerResolver.KnownPlayer target = resolution.player();
+        return switch (operation) {
+            case "status" -> status(sender, target);
+            case "grant" -> grant(sender, target);
+            case "reset" -> reset(sender, label, arguments, target);
+            default -> {
+                sendUsage(sender, label);
+                yield true;
+            }
+        };
+    }
+
+    private boolean sleepCount(CommandSender sender, String label, String[] arguments) {
+        if (arguments.length != 2) {
+            sendUsage(sender, label);
+            return true;
+        }
+        String action = arguments[1].toLowerCase(Locale.ROOT);
+        if ("status".equals(action)) {
+            sender.sendMessage("Concealed players are "
+                    + policyDescription(administration.sleepCountPolicy())
+                    + " sleep-percentage calculations.");
+            return true;
+        }
+        SleepCountPolicy policy = switch (action) {
+            case "include" -> SleepCountPolicy.INCLUDE;
+            case "exclude" -> SleepCountPolicy.EXCLUDE;
+            default -> null;
+        };
+        if (policy == null) {
+            sendUsage(sender, label);
+            return true;
+        }
+        administration.setSleepCountPolicy(policy).whenComplete((result, failure) -> mainThread.accept(() -> {
+            if (failure != null) {
+                sender.sendMessage("Unable to persist the sleep-count policy; check the server log.");
+                return;
+            }
+            administration.refreshSleepCountPolicy();
+            sender.sendMessage(result.changed()
+                    ? "Concealed players are now " + policyDescription(policy)
+                            + " sleep-percentage calculations."
+                    : "Concealed players are already " + policyDescription(policy)
+                            + " sleep-percentage calculations.");
+            auditLog.accept("stealthadmin sleepcount administrator=" + sender.getName()
+                    + " policy=" + policy.persistedValue() + " changed=" + result.changed());
+        }));
+        return true;
+    }
+
+    private boolean status(CommandSender sender, KnownPlayerResolver.KnownPlayer target) {
+        StealthAdministrationService.PlayerStatus status = administration.status(target.playerId());
+        sender.sendMessage("Stealth status for " + displayName(target) + " (" + target.playerId() + "):");
+        sender.sendMessage("progress=" + StealthProgressFormatter.duration(status.accumulatedMillis())
+                + "/" + StealthProgressFormatter.duration(unlockThreshold.toMillis())
+                + " unlocked=" + yesNo(status.unlocked())
+                + " prepared=" + yesNo(status.preparedLogin())
+                + " concealed=" + yesNo(status.concealed())
+                + " qualifying=" + yesNo(status.qualifyingNow()));
+        return true;
+    }
+
+    private boolean grant(CommandSender sender, KnownPlayerResolver.KnownPlayer target) {
+        CompletableFuture<StealthAdministrationService.ChangeResult> grant =
+                administration.grant(target.playerId(), target.name());
+        grant.whenComplete((result, failure) -> mainThread.accept(() -> {
+            if (failure != null) {
+                sender.sendMessage("Unable to persist the stealth grant; check the server log.");
+                return;
+            }
+            sender.sendMessage(result.changed()
+                    ? "Stealth unlock granted to " + displayName(target) + "."
+                    : displayName(target) + " already has the stealth unlock.");
+            auditLog.accept("stealthadmin grant administrator=" + sender.getName()
+                    + " target=" + target.playerId() + " changed=" + result.changed());
+        }));
+        return true;
+    }
+
+    private boolean reset(
+            CommandSender sender,
+            String label,
+            String[] arguments,
+            KnownPlayerResolver.KnownPlayer target) {
+        if (arguments.length != 3 || !"confirm".equalsIgnoreCase(arguments[2])) {
+            sender.sendMessage("Confirm the complete reset with /" + label + " reset " + arguments[1] + " confirm");
+            return true;
+        }
+        administration.reset(target.playerId(), target.name(), target.onlinePlayer())
+                .whenComplete((ignored, failure) -> mainThread.accept(() -> {
+                    if (failure != null) {
+                        sender.sendMessage("Unable to persist the stealth reset; check the server log.");
+                        return;
+                    }
+                    sender.sendMessage("Stealth reset complete for " + displayName(target) + ".");
+                    auditLog.accept("stealthadmin reset administrator=" + sender.getName()
+                            + " target=" + target.playerId());
+                }));
+        return true;
+    }
+
+    private static void sendUsage(CommandSender sender, String label) {
+        sender.sendMessage("Usage: /" + label + " <status <player|uuid>|grant <player|uuid>|reset <player|uuid> confirm|list [unlocked]|sleepcount <status|include|exclude>>");
+    }
+
+    private static String displayName(KnownPlayerResolver.KnownPlayer player) {
+        return player.name() == null ? player.playerId().toString() : player.name();
+    }
+
+    private static String policyDescription(SleepCountPolicy policy) {
+        return policy == SleepCountPolicy.EXCLUDE ? "excluded from" : "included in";
+    }
+
+    private static String yesNo(boolean value) {
+        return value ? "yes" : "no";
+    }
+}

src/main/java/games/dmg/spigotstealth/StealthAdminJoinListener.java

@@ -0,0 +1,49 @@
+package games.dmg.spigotstealth;
+
+import java.util.Collection;
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+import java.util.function.Supplier;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerJoinEvent;
+
+/** Private administrative notices after the HIGHEST-priority session transition. */
+public final class StealthAdminJoinListener implements Listener {
+    private static final String PERMISSION = "spigotstealth.admin";
+    private static final String HINT = " Use /stealthadmin list to see who.";
+    private final StealthSessionService sessions;
+    private final Supplier<? extends Collection<? extends Player>> onlinePlayers;
+
+    public StealthAdminJoinListener(
+            StealthSessionService sessions,
+            Supplier<? extends Collection<? extends Player>> onlinePlayers) {
+        this.sessions = Objects.requireNonNull(sessions, "sessions");
+        this.onlinePlayers = Objects.requireNonNull(onlinePlayers, "onlinePlayers");
+    }
+
+    @EventHandler(priority = EventPriority.MONITOR)
+    public void onJoin(PlayerJoinEvent event) {
+        Player joining = event.getPlayer();
+        Set<UUID> concealed = sessions.concealedPlayerIds();
+        int count = concealed.size();
+        if (count == 0) {
+            return;
+        }
+        String quantity = count + (count == 1 ? " player is" : " players are");
+        if (joining.hasPermission(PERMISSION)) {
+            joining.sendMessage("[Stealth] " + quantity + " invisible." + HINT);
+        }
+        if (concealed.contains(joining.getUniqueId())) {
+            String notice = "[Stealth] An invisible player joined. " + quantity + " now invisible." + HINT;
+            for (Player observer : onlinePlayers.get()) {
+                if (!observer.getUniqueId().equals(joining.getUniqueId()) && observer.hasPermission(PERMISSION)) {
+                    observer.sendMessage(notice);
+                }
+            }
+        }
+    }
+}

src/main/java/games/dmg/spigotstealth/StealthAdministrationService.java

@@ -0,0 +1,123 @@
+package games.dmg.spigotstealth;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Objects;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
+import org.bukkit.entity.Player;
+
+/** Durable administrative operations over player stealth state. */
+public final class StealthAdministrationService {
+    private final StealthStateManager stateManager;
+    private final QualifyingInvisibilityService progression;
+    private final IdentityPresentation presentation;
+    private final Consumer<UUID> unlockNotifier;
+    private final Supplier<? extends Collection<? extends Player>> onlinePlayers;
+
+    public StealthAdministrationService(
+            StealthStateManager stateManager,
+            QualifyingInvisibilityService progression,
+            IdentityPresentation presentation,
+            Consumer<UUID> unlockNotifier,
+            Supplier<? extends Collection<? extends Player>> onlinePlayers) {
+        this.stateManager = Objects.requireNonNull(stateManager, "stateManager");
+        this.progression = Objects.requireNonNull(progression, "progression");
+        this.presentation = Objects.requireNonNull(presentation, "presentation");
+        this.unlockNotifier = Objects.requireNonNull(unlockNotifier, "unlockNotifier");
+        this.onlinePlayers = Objects.requireNonNull(onlinePlayers, "onlinePlayers");
+    }
+
+    public SleepCountPolicy sleepCountPolicy() {
+        return stateManager.snapshot().sleepCountPolicy();
+    }
+
+    public CompletableFuture<ChangeResult> setSleepCountPolicy(SleepCountPolicy policy) {
+        Objects.requireNonNull(policy, "policy");
+        AtomicBoolean changed = new AtomicBoolean();
+        return stateManager.update(state -> {
+            if (state.sleepCountPolicy() == policy) {
+                return state;
+            }
+            changed.set(true);
+            return state.withSleepCountPolicy(policy);
+        }).thenApply(ignored -> new ChangeResult(changed.get()));
+    }
+
+    public void refreshSleepCountPolicy() {
+        presentation.refreshSleepCountPolicy();
+    }
+
+    public PlayerStatus status(UUID playerId) {
+        PlayerStealthState player = stateManager.snapshot().player(playerId);
+        return new PlayerStatus(
+                progression.currentAccumulatedMillis(playerId),
+                player.unlocked(),
+                player.preparedLogin(),
+                player.concealed(),
+                progression.isQualifying(playerId));
+    }
+
+    public CompletableFuture<ChangeResult> grant(UUID playerId, String playerName) {
+        AtomicBoolean changed = new AtomicBoolean();
+        CompletableFuture<Void> saved = stateManager.update(state -> {
+            PlayerStealthState player = state.player(playerId).withLastKnownName(playerName);
+            if (player.unlocked()) {
+                return state.withPlayer(player);
+            }
+            changed.set(true);
+            return state.withPlayer(player.withProgress(player.accumulatedMillis(), true));
+        });
+        return saved.thenApply(ignored -> {
+            if (changed.get()) {
+                unlockNotifier.accept(playerId);
+            }
+            return new ChangeResult(changed.get());
+        });
+    }
+
+    public CompletableFuture<Void> reset(UUID playerId, String playerName, Player onlinePlayer) {
+        CompletableFuture<Void> stopped = progression.stop(playerId);
+        CompletableFuture<Void> reset = stateManager.update(state -> {
+            PlayerStealthState player = state.player(playerId);
+            PlayerStealthState cleared = new PlayerStealthState(
+                    playerId, playerName, 0L, false, false, false, null, player.unknownFields());
+            return state.withPlayer(cleared);
+        });
+        if (onlinePlayer != null) {
+            presentation.reveal(onlinePlayer);
+        }
+        return CompletableFuture.allOf(stopped, reset);
+    }
+
+    public List<String> unlockedPlayerNames() {
+        return stateManager.snapshot().players().entrySet().stream()
+                .filter(entry -> entry.getValue().unlocked())
+                .map(entry -> {
+                    String name = entry.getValue().lastKnownName();
+                    return name == null || name.isBlank() ? entry.getKey().toString() : name;
+                })
+                .sorted(String.CASE_INSENSITIVE_ORDER)
+                .toList();
+    }
+
+    public List<String> concealedOnlineNames() {
+        return onlinePlayers.get().stream()
+                .filter(player -> stateManager.snapshot().player(player.getUniqueId()).concealed())
+                .map(Player::getName)
+                .sorted(String.CASE_INSENSITIVE_ORDER)
+                .toList();
+    }
+
+    public record PlayerStatus(
+            long accumulatedMillis,
+            boolean unlocked,
+            boolean preparedLogin,
+            boolean concealed,
+            boolean qualifyingNow) { }
+
+    public record ChangeResult(boolean changed) { }
+}

src/main/java/games/dmg/spigotstealth/StealthChatMasker.java

@@ -0,0 +1,117 @@
+package games.dmg.spigotstealth;
+
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonParser;
+import java.util.Locale;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/** Masks semantic name slots, never searching/replacing user-authored message text. */
+public final class StealthChatMasker {
+    private static final Set<String> NAME_FIRST_TRANSLATIONS = Set.of(
+            "chat.type.text", "chat.type.announcement", "chat.type.emote",
+            "commands.message.display.incoming", "commands.message.display.outgoing",
+            "chat.type.advancement.task", "chat.type.advancement.goal", "chat.type.advancement.challenge");
+    private final Set<String> names;
+
+    public StealthChatMasker(Set<String> concealedNames) {
+        names = concealedNames.stream().map(name -> name.toLowerCase(Locale.ROOT)).collect(Collectors.toUnmodifiableSet());
+    }
+
+    public boolean isConcealedName(String text) {
+        return names.contains(text.toLowerCase(Locale.ROOT));
+    }
+
+    public String maskAnnouncement(String json) {
+        try {
+            JsonElement component = JsonParser.parseString(json);
+            return maskAnnouncement(component) ? component.toString() : json;
+        } catch (JsonParseException | IllegalStateException exception) {
+            return json;
+        }
+    }
+
+    public String maskDisplayName(String json) {
+        try {
+            return isConcealedName(plainName(JsonParser.parseString(json))) ? anonymous().toString() : json;
+        } catch (JsonParseException | IllegalStateException exception) {
+            return json;
+        }
+    }
+
+    private boolean maskAnnouncement(JsonElement component) {
+        boolean changed = false;
+        if (component.isJsonArray()) {
+            for (JsonElement child : component.getAsJsonArray()) {
+                changed |= maskAnnouncement(child);
+            }
+            if (changed && !component.getAsJsonArray().isEmpty()) {
+                clearInheritedActions(component.getAsJsonArray().get(0));
+            }
+        } else if (component.isJsonObject()) {
+            JsonObject object = component.getAsJsonObject();
+            // Translation arguments other than the explicitly known name slot are message content.
+            if (object.has("translate") && object.get("translate").isJsonPrimitive()
+                    && NAME_FIRST_TRANSLATIONS.contains(object.get("translate").getAsString())
+                    && object.has("with") && object.get("with").isJsonArray()) {
+                JsonArray arguments = object.getAsJsonArray("with");
+                if (!arguments.isEmpty() && isConcealedName(plainName(arguments.get(0)))) {
+                    arguments.set(0, anonymous());
+                    changed = true;
+                }
+            }
+            if (object.has("extra")) {
+                changed |= maskAnnouncement(object.get("extra"));
+            }
+            // Prevent masked descendants from inheriting an identifying action from their parent.
+            if (changed) {
+                clearInheritedActions(object);
+            }
+        }
+        return changed;
+    }
+
+    private static void clearInheritedActions(JsonElement component) {
+        if (component.isJsonObject()) {
+            for (String key : Set.of("hoverEvent", "clickEvent", "hover_event", "click_event", "insertion")) {
+                component.getAsJsonObject().remove(key);
+            }
+        } else if (component.isJsonArray() && !component.getAsJsonArray().isEmpty()) {
+            clearInheritedActions(component.getAsJsonArray().get(0));
+        }
+    }
+
+    private static String plainName(JsonElement component) {
+        if (component.isJsonPrimitive()) {
+            return component.getAsString();
+        }
+        StringBuilder text = new StringBuilder();
+        if (component.isJsonArray()) {
+            for (JsonElement child : component.getAsJsonArray()) {
+                text.append(plainName(child));
+            }
+        } else if (component.isJsonObject()) {
+            JsonObject object = component.getAsJsonObject();
+            if (object.has("text") && object.get("text").isJsonPrimitive()) {
+                text.append(object.get("text").getAsString());
+            }
+            if (object.has("extra")) {
+                text.append(plainName(object.get("extra")));
+            }
+        }
+        return text.toString();
+    }
+
+    private static JsonObject anonymous() {
+        JsonObject alias = new JsonObject();
+        alias.addProperty("text", "Anonymous");
+        alias.addProperty("obfuscated", true);
+        alias.add("hoverEvent", com.google.gson.JsonNull.INSTANCE);
+        alias.add("clickEvent", com.google.gson.JsonNull.INSTANCE);
+        alias.addProperty("insertion", "");
+        return alias;
+    }
+}

src/main/java/games/dmg/spigotstealth/StealthCommand.java

@@ -0,0 +1,62 @@
+package games.dmg.spigotstealth;
+
+import java.util.List;
+import java.util.Locale;
+import java.util.Objects;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabCompleter;
+import org.bukkit.entity.Player;
+
+/** Player-facing progress command. */
+public final class StealthCommand implements CommandExecutor, TabCompleter {
+    private final StealthStateManager stateManager;
+    private final QualifyingInvisibilityService progression;
+    private final StealthSettings settings;
+
+    public StealthCommand(
+            StealthStateManager stateManager,
+            QualifyingInvisibilityService progression,
+            StealthSettings settings) {
+        this.stateManager = Objects.requireNonNull(stateManager, "stateManager");
+        this.progression = Objects.requireNonNull(progression, "progression");
+        this.settings = Objects.requireNonNull(settings, "settings");
+    }
+
+    @Override
+    public List<String> onTabComplete(
+            CommandSender sender, Command command, String label, String[] arguments) {
+        if (arguments.length == 1 && "progress".startsWith(arguments[0].toLowerCase(Locale.ROOT))) {
+            return List.of("progress");
+        }
+        return List.of();
+    }
+
+    @Override
+    public boolean onCommand(CommandSender sender, Command command, String label, String[] arguments) {
+        if (!(sender instanceof Player player)) {
+            sender.sendMessage("Only players can check personal stealth progress.");
+            return true;
+        }
+        if (arguments.length != 1 || !"progress".equals(arguments[0].toLowerCase(Locale.ROOT))) {
+            sender.sendMessage("Usage: /" + label + " progress");
+            return true;
+        }
+        PlayerStealthState state = stateManager.snapshot().player(player.getUniqueId());
+        long accumulated = progression.currentAccumulatedMillis(player.getUniqueId());
+        if (state.unlocked()) {
+            player.sendMessage("Stealth is unlocked.");
+            player.sendMessage("Drink an invisibility potion and log out while invisible to conceal your next login.");
+            return true;
+        }
+        long target = settings.unlockThreshold().toMillis();
+        long remaining = Math.max(0L, target - accumulated);
+        String message = settings.progressMessage()
+                .replace("{progress}", StealthProgressFormatter.duration(accumulated))
+                .replace("{target}", StealthProgressFormatter.duration(target))
+                .replace("{remaining}", StealthProgressFormatter.duration(remaining));
+        player.sendMessage(message);
+        return true;
+    }
+}

src/main/java/games/dmg/spigotstealth/StealthProgressFormatter.java

@@ -0,0 +1,32 @@
+package games.dmg.spigotstealth;
+
+/** Human-readable duration and progress presentation. */
+public final class StealthProgressFormatter {
+    private StealthProgressFormatter() { }
+
+    public static String duration(long milliseconds) {
+        long totalSeconds = Math.max(0L, milliseconds) / 1000L;
+        long hours = totalSeconds / 3600L;
+        long minutes = (totalSeconds % 3600L) / 60L;
+        long seconds = totalSeconds % 60L;
+        StringBuilder formatted = new StringBuilder();
+        if (hours > 0L) {
+            formatted.append(hours).append('h');
+        }
+        if (minutes > 0L) {
+            appendSpace(formatted);
+            formatted.append(minutes).append('m');
+        }
+        if (seconds > 0L || formatted.length() == 0) {
+            appendSpace(formatted);
+            formatted.append(seconds).append('s');
+        }
+        return formatted.toString();
+    }
+
+    private static void appendSpace(StringBuilder value) {
+        if (value.length() > 0) {
+            value.append(' ');
+        }
+    }
+}

src/main/java/games/dmg/spigotstealth/StealthSessionListener.java

@@ -0,0 +1,57 @@
+package games.dmg.spigotstealth;
+
+import java.util.Objects;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.event.player.PlayerQuitEvent;
+import org.bukkit.event.player.PlayerRespawnEvent;
+
+/** Applies session transitions and identity presentation on Bukkit lifecycle events. */
+public final class StealthSessionListener implements Listener {
+    private final StealthSessionService sessions;
+    private final IdentityPresentation presentation;
+    private final String concealedMessage;
+
+    public StealthSessionListener(
+            StealthSessionService sessions,
+            IdentityPresentation presentation,
+            String concealedMessage) {
+        this.sessions = Objects.requireNonNull(sessions, "sessions");
+        this.presentation = Objects.requireNonNull(presentation, "presentation");
+        this.concealedMessage = Objects.requireNonNull(concealedMessage, "concealedMessage");
+    }
+
+    @EventHandler(priority = EventPriority.HIGHEST)
+    public void onJoin(PlayerJoinEvent event) {
+        Player player = event.getPlayer();
+        StealthSessionService.LoginTransition transition = sessions.login(player.getUniqueId(), player.getName());
+        if (transition.concealed()) {
+            event.setJoinMessage(null);
+            presentation.conceal(player);
+            player.sendMessage(concealedMessage);
+        } else {
+            presentation.reveal(player);
+        }
+        presentation.refreshForObserver(player);
+    }
+
+    @EventHandler(priority = EventPriority.HIGHEST)
+    public void onQuit(PlayerQuitEvent event) {
+        Player player = event.getPlayer();
+        if (sessions.isConcealed(player.getUniqueId())) {
+            event.setQuitMessage(null);
+        }
+        presentation.reveal(player);
+        sessions.disconnect(player.getUniqueId());
+    }
+
+    @EventHandler(priority = EventPriority.MONITOR)
+    public void onRespawn(PlayerRespawnEvent event) {
+        if (sessions.isConcealed(event.getPlayer().getUniqueId())) {
+            presentation.conceal(event.getPlayer());
+        }
+    }
+}

src/main/java/games/dmg/spigotstealth/StealthSessionService.java

@@ -0,0 +1,69 @@
+package games.dmg.spigotstealth;
+
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/** Owns prepared-login and current concealed-session state transitions. */
+public final class StealthSessionService {
+    private final StealthStateManager stateManager;
+    private final QualifyingInvisibilityService progression;
+    private final Set<UUID> concealedOnlinePlayerIds = ConcurrentHashMap.newKeySet();
+
+    public StealthSessionService(
+            StealthStateManager stateManager,
+            QualifyingInvisibilityService progression) {
+        this.stateManager = Objects.requireNonNull(stateManager, "stateManager");
+        this.progression = Objects.requireNonNull(progression, "progression");
+    }
+
+    public CompletableFuture<Void> disconnect(UUID playerId) {
+        concealedOnlinePlayerIds.remove(playerId);
+        boolean qualifyingAtDisconnect = progression.isQualifying(playerId);
+        return progression.stop(playerId).thenCompose(ignored -> stateManager.update(state -> {
+            PlayerStealthState player = state.player(playerId);
+            boolean prepareNextLogin = qualifyingAtDisconnect && player.unlocked();
+            return state.withPlayer(player.withSession(prepareNextLogin, false));
+        }));
+    }
+
+    public LoginTransition login(UUID playerId, String playerName) {
+        AtomicBoolean concealed = new AtomicBoolean();
+        CompletableFuture<Void> saved = stateManager.update(state -> {
+            PlayerStealthState player = state.player(playerId).withLastKnownName(playerName);
+            boolean conceal = player.unlocked() && player.preparedLogin();
+            concealed.set(conceal);
+            return state.withPlayer(player.withSession(false, conceal).withQualifyingSince(null));
+        });
+        if (concealed.get()) {
+            concealedOnlinePlayerIds.add(playerId);
+        } else {
+            concealedOnlinePlayerIds.remove(playerId);
+        }
+        return new LoginTransition(concealed.get(), saved);
+    }
+
+    public CompletableFuture<Void> endConcealment(UUID playerId) {
+        concealedOnlinePlayerIds.remove(playerId);
+        return stateManager.update(state -> {
+            PlayerStealthState player = state.player(playerId);
+            return state.withPlayer(player.withSession(player.preparedLogin(), false));
+        });
+    }
+
+    public boolean isConcealed(UUID playerId) {
+        return stateManager.snapshot().player(playerId).concealed();
+    }
+
+    public Set<UUID> concealedPlayerIds() {
+        PersistentStealthState state = stateManager.snapshot();
+        return concealedOnlinePlayerIds.stream()
+                .filter(playerId -> state.player(playerId).concealed())
+                .collect(java.util.stream.Collectors.toUnmodifiableSet());
+    }
+
+    public record LoginTransition(boolean concealed, CompletableFuture<Void> saved) { }
+}

src/main/java/games/dmg/spigotstealth/TabListController.java

@@ -0,0 +1,11 @@
+package games.dmg.spigotstealth;
+
+import java.util.UUID;
+import org.bukkit.entity.Player;
+
+/** Packet-level tab-list operations that do not hide the physical player entity. */
+public interface TabListController {
+    void remove(Player observer, UUID targetPlayerId);
+
+    void add(Player observer, Player target);
+}

src/main/java/games/dmg/spigotstealth/YamlStealthStateRepository.java

@@ -17,7 +17,7 @@ import org.bukkit.configuration.file.YamlConfiguration;
 
 /** Defensive YAML repository using atomic file replacement where available. */
 public final class YamlStealthStateRepository implements StealthStateRepository {
-    private static final Set<String> ROOT_FIELDS = Set.of("schema-version", "players");
+    private static final Set<String> ROOT_FIELDS = Set.of("schema-version", "sleep-count-policy", "players");
     private static final Set<String> PLAYER_FIELDS = Set.of(
             "last-known-name", "accumulated-millis", "unlocked", "prepared-login", "concealed", "qualifying-since");
     private final Path stateFile;
@@ -53,7 +53,10 @@ public final class YamlStealthStateRepository implements StealthStateRepository
                 }
             }
         }
-        return new PersistentStealthState(players, unknownRoot);
+        return new PersistentStealthState(
+                players,
+                SleepCountPolicy.fromPersisted(yaml.get("sleep-count-policy")),
+                unknownRoot);
     }
 
     @Override
@@ -61,6 +64,7 @@ public final class YamlStealthStateRepository implements StealthStateRepository
         YamlConfiguration yaml = new YamlConfiguration();
         state.unknownFields().forEach(yaml::set);
         yaml.set("schema-version", 1);
+        yaml.set("sleep-count-policy", state.sleepCountPolicy().persistedValue());
         for (PlayerStealthState player : state.players().values()) {
             String base = "players." + player.playerId() + ".";
             player.unknownFields().forEach((key, value) -> yaml.set(base + key, value));

src/main/resources/plugin.yml

@@ -4,6 +4,7 @@ main: games.dmg.spigotstealth.SpigotStealthPlugin
 api-version: "1.20"
 description: Rewards invisibility potion use with identity-concealed sessions.
 author: dmg.games
+depend: [ProtocolLib]
 commands:
   stealth:
     description: View and use Spigot Stealth features.
@@ -11,7 +12,7 @@ commands:
     permission: spigotstealth.use
   stealthadmin:
     description: Inspect and administer Spigot Stealth.
-    usage: /stealthadmin <status|grant|reset|list>
+    usage: /stealthadmin <status <player|uuid>|grant <player|uuid>|reset <player|uuid> confirm|list [unlocked]|sleepcount <status|include|exclude>>
     permission: spigotstealth.admin
 permissions:
   spigotstealth.use:

src/test/java/games/dmg/spigotstealth/BukkitIdentityPresentationTest.java

@@ -0,0 +1,128 @@
+package games.dmg.spigotstealth;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.atomic.AtomicReference;
+import org.bukkit.entity.Player;
+import org.bukkit.scoreboard.Scoreboard;
+import org.bukkit.scoreboard.Team;
+import org.junit.jupiter.api.Test;
+
+class BukkitIdentityPresentationTest {
+    @Test
+    void excludedConcealmentIgnoresSleepCountAndRestoresPreviousState() {
+        UUID targetId = UUID.randomUUID();
+        Player target = player(targetId, "Alex");
+        when(target.isSleepingIgnored()).thenReturn(false);
+        Scoreboard scoreboard = mock(Scoreboard.class);
+        Team team = mock(Team.class);
+        when(scoreboard.getTeam(BukkitIdentityPresentation.teamName(targetId))).thenReturn(team);
+        BukkitIdentityPresentation presentation = new BukkitIdentityPresentation(
+                () -> List.of(target), scoreboard, mock(TabListController.class));
+
+        when(target.getDisplayName()).thenReturn("Original Alex");
+        presentation.conceal(target);
+        presentation.conceal(target);
+        presentation.reveal(target);
+
+        verify(target).setDisplayName("Original Alex");
+        org.junit.jupiter.api.Assertions.assertTrue(presentation.concealedNames().isEmpty());
+        verify(target, org.mockito.Mockito.times(2)).setSleepingIgnored(true);
+        verify(target).setSleepingIgnored(false);
+    }
+
+    @Test
+    void includedConcealmentDoesNotChangeOrdinarySleepParticipation() {
+        UUID targetId = UUID.randomUUID();
+        Player target = player(targetId, "Alex");
+        Scoreboard scoreboard = mock(Scoreboard.class);
+        Team team = mock(Team.class);
+        when(scoreboard.getTeam(BukkitIdentityPresentation.teamName(targetId))).thenReturn(team);
+        BukkitIdentityPresentation presentation = new BukkitIdentityPresentation(
+                () -> List.of(target),
+                scoreboard,
+                mock(TabListController.class),
+                () -> SleepCountPolicy.INCLUDE);
+
+        presentation.conceal(target);
+
+        verify(target, never()).setSleepingIgnored(org.mockito.ArgumentMatchers.anyBoolean());
+    }
+
+    @Test
+    void policyChangesImmediatelyRestoreAndReapplyConcealedSleepParticipation() {
+        UUID targetId = UUID.randomUUID();
+        Player target = player(targetId, "Alex");
+        when(target.isSleepingIgnored()).thenReturn(false);
+        Scoreboard scoreboard = mock(Scoreboard.class);
+        Team team = mock(Team.class);
+        when(scoreboard.getTeam(BukkitIdentityPresentation.teamName(targetId))).thenReturn(team);
+        AtomicReference<SleepCountPolicy> policy = new AtomicReference<>(SleepCountPolicy.EXCLUDE);
+        BukkitIdentityPresentation presentation = new BukkitIdentityPresentation(
+                () -> List.of(target), scoreboard, mock(TabListController.class), policy::get);
+        presentation.conceal(target);
+
+        policy.set(SleepCountPolicy.INCLUDE);
+        presentation.refreshSleepCountPolicy();
+        policy.set(SleepCountPolicy.EXCLUDE);
+        presentation.refreshSleepCountPolicy();
+
+        verify(target, org.mockito.Mockito.times(2)).setSleepingIgnored(true);
+        verify(target).setSleepingIgnored(false);
+    }
+
+    @Test
+    void concealRemovesTabEntryAndScramblesNameTagWithoutHidingEntity() {
+        UUID targetId = UUID.randomUUID();
+        Player target = player(targetId, "Alex");
+        Player observer = player(UUID.randomUUID(), "Morgan");
+        Scoreboard scoreboard = mock(Scoreboard.class);
+        Team team = mock(Team.class);
+        when(scoreboard.getTeam(BukkitIdentityPresentation.teamName(targetId))).thenReturn(null);
+        when(scoreboard.registerNewTeam(BukkitIdentityPresentation.teamName(targetId))).thenReturn(team);
+        TabListController tabLists = mock(TabListController.class);
+        BukkitIdentityPresentation presentation = new BukkitIdentityPresentation(
+                () -> List.of(target, observer), scoreboard, tabLists);
+
+        presentation.conceal(target);
+
+        verify(team).setOption(Team.Option.NAME_TAG_VISIBILITY, Team.OptionStatus.ALWAYS);
+        verify(team).setPrefix("§k");
+        verify(team).setSuffix("§r");
+        verify(target).setDisplayName("§kAnonymous§r");
+        org.junit.jupiter.api.Assertions.assertEquals(java.util.Set.of("Alex"), presentation.concealedNames());
+        verify(team).addEntry("Alex");
+        verify(tabLists).remove(observer, targetId);
+        verify(observer, never()).hidePlayer(org.mockito.ArgumentMatchers.any(), org.mockito.ArgumentMatchers.any());
+    }
+
+    @Test
+    void newObserverHasEveryConcealedPlayerRemovedFromTab() {
+        UUID targetId = UUID.randomUUID();
+        Player target = player(targetId, "Alex");
+        Player observer = player(UUID.randomUUID(), "Morgan");
+        Scoreboard scoreboard = mock(Scoreboard.class);
+        Team team = mock(Team.class);
+        when(scoreboard.getTeam(BukkitIdentityPresentation.teamName(targetId))).thenReturn(team);
+        TabListController tabLists = mock(TabListController.class);
+        BukkitIdentityPresentation presentation = new BukkitIdentityPresentation(
+                () -> List.of(target, observer), scoreboard, tabLists);
+        presentation.conceal(target);
+
+        presentation.refreshForObserver(observer);
+
+        verify(tabLists, org.mockito.Mockito.atLeastOnce()).remove(observer, targetId);
+    }
+
+    private static Player player(UUID playerId, String name) {
+        Player player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(playerId);
+        when(player.getName()).thenReturn(name);
+        return player;
+    }
+}

src/test/java/games/dmg/spigotstealth/BukkitUnlockNotifierTest.java

@@ -0,0 +1,27 @@
+package games.dmg.spigotstealth;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.UUID;
+import java.util.function.Consumer;
+import org.bukkit.entity.Player;
+import org.junit.jupiter.api.Test;
+
+class BukkitUnlockNotifierTest {
+    @Test
+    void sendsFullScreenTitleAndChatMessageToOnlinePlayer() {
+        UUID playerId = UUID.randomUUID();
+        Player player = mock(Player.class);
+        when(player.isOnline()).thenReturn(true);
+        Consumer<Runnable> immediateMainThread = Runnable::run;
+        BukkitUnlockNotifier notifier = new BukkitUnlockNotifier(
+                ignored -> player, immediateMainThread, "Stealth unlocked!");
+
+        notifier.accept(playerId);
+
+        verify(player).sendTitle("Stealth Unlocked", "Your identity can now be concealed", 10, 100, 20);
+        verify(player).sendMessage("Stealth unlocked!");
+    }
+}

src/test/java/games/dmg/spigotstealth/IdentityPacketFieldsTest.java

@@ -0,0 +1,32 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import org.junit.jupiter.api.Test;
+
+class IdentityPacketFieldsTest {
+    private final StealthChatMasker masker = new StealthChatMasker(Set.of("Secret"));
+
+    record Entry(String text, Optional<String> tooltip) { }
+    record Bound(int chatType, String name, Optional<String> targetName) { }
+
+    @Test
+    void filtersModernSuggestionEntriesWithoutChangingOrdinaryEntries() throws ReflectiveOperationException {
+        Entry ordinary = new Entry("Someone", Optional.of("help"));
+        List<Entry> entries = List.of(new Entry("sEcReT", Optional.empty()), ordinary);
+        assertEquals(List.of(ordinary), IdentityPacketFields.filterEntries(entries, masker));
+        assertEquals(2, entries.size());
+    }
+
+    @Test
+    void rebuildsDisplayNameRecordWithoutMutatingOriginal() throws ReflectiveOperationException {
+        Bound original = new Bound(42, "Secret", Optional.of("Secret"));
+        Object copy = IdentityPacketFields.mapRecord(original,
+                value -> value.equals("Secret") ? "Anonymous" : value);
+        assertEquals(new Bound(42, "Anonymous", Optional.of("Anonymous")), copy);
+        assertEquals("Secret", original.name());
+    }
+}

src/test/java/games/dmg/spigotstealth/InvisibilityEffectListenerTest.java

@@ -0,0 +1,68 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.time.ZoneOffset;
+import java.util.Map;
+import java.util.UUID;
+import java.util.concurrent.atomic.AtomicLong;
+import org.bukkit.entity.Player;
+import org.bukkit.event.entity.EntityPotionEffectEvent;
+import org.junit.jupiter.api.Test;
+
+class InvisibilityEffectListenerTest {
+    @Test
+    void onlyPotionDrinkCauseStartsQualifyingInvisibility() {
+        UUID playerId = UUID.randomUUID();
+        AtomicLong nanos = new AtomicLong();
+        try (StealthStateManager manager = manager()) {
+            QualifyingInvisibilityService service = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), nanos::get, ignored -> { });
+            InvisibilityEffectListener listener = new InvisibilityEffectListener(
+                    service, Clock.fixed(Instant.EPOCH, ZoneOffset.UTC));
+
+            Player player = player(playerId);
+            listener.handlePotionEffect(player, true, EntityPotionEffectEvent.Cause.POTION_SPLASH, EntityPotionEffectEvent.Action.ADDED);
+            assertFalse(service.isQualifying(playerId));
+            listener.handlePotionEffect(player, true, EntityPotionEffectEvent.Cause.COMMAND, EntityPotionEffectEvent.Action.CHANGED);
+            assertFalse(service.isQualifying(playerId));
+            listener.handlePotionEffect(player, true, EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED);
+            assertTrue(service.isQualifying(playerId));
+        }
+    }
+
+    @Test
+    void anyLaterNonDrinkChangeStopsTheQualifyingInterval() {
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            QualifyingInvisibilityService service = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            InvisibilityEffectListener listener = new InvisibilityEffectListener(service, Clock.systemUTC());
+            Player player = player(playerId);
+            listener.handlePotionEffect(player, true, EntityPotionEffectEvent.Cause.POTION_DRINK, EntityPotionEffectEvent.Action.ADDED);
+            listener.handlePotionEffect(player, true, EntityPotionEffectEvent.Cause.PLUGIN, EntityPotionEffectEvent.Action.CHANGED);
+            assertFalse(service.isQualifying(playerId));
+        }
+    }
+
+    private static Player player(UUID playerId) {
+        Player player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(playerId);
+        when(player.getName()).thenReturn("Alex");
+        return player;
+    }
+
+    private static StealthStateManager manager() {
+        StealthStateRepository repository = new StealthStateRepository() {
+            @Override public PersistentStealthState load() { return new PersistentStealthState(Map.of(), Map.of()); }
+            @Override public void save(PersistentStealthState state) { }
+        };
+        return new StealthStateManager(repository, new PersistentStealthState(Map.of(), Map.of()));
+    }
+}

src/test/java/games/dmg/spigotstealth/KnownPlayerResolverTest.java

@@ -0,0 +1,33 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import org.junit.jupiter.api.Test;
+
+class KnownPlayerResolverTest {
+    @Test
+    void resolvesKnownOfflinePlayerByExactNameOrUuid() {
+        UUID playerId = UUID.randomUUID();
+        PlayerStealthState player = PlayerStealthState.empty(playerId).withLastKnownName("Alex");
+        PersistentStealthState state = new PersistentStealthState(Map.of(playerId, player), Map.of());
+        KnownPlayerResolver resolver = new KnownPlayerResolver(() -> state, List::of);
+        assertEquals(playerId, resolver.resolve("alex").player().playerId());
+        assertEquals(playerId, resolver.resolve(playerId.toString()).player().playerId());
+    }
+
+    @Test
+    void reportsAmbiguousAndUnknownNamesWithoutCreatingRecords() {
+        UUID first = UUID.randomUUID();
+        UUID second = UUID.randomUUID();
+        PersistentStealthState state = new PersistentStealthState(Map.of(
+                first, PlayerStealthState.empty(first).withLastKnownName("Alex"),
+                second, PlayerStealthState.empty(second).withLastKnownName("ALEX")), Map.of());
+        KnownPlayerResolver resolver = new KnownPlayerResolver(() -> state, List::of);
+        assertEquals(KnownPlayerResolver.Status.AMBIGUOUS, resolver.resolve("alex").status());
+        assertEquals(KnownPlayerResolver.Status.UNKNOWN, resolver.resolve("nobody").status());
+        assertEquals(2, state.players().size());
+    }
+}

src/test/java/games/dmg/spigotstealth/PluginMetadataTest.java

@@ -26,6 +26,7 @@ class PluginMetadataTest {
             assertEquals("games.dmg.spigotstealth.SpigotStealthPlugin", metadata.get("main"));
             assertNotNull(metadata.get("commands"));
             assertNotNull(metadata.get("permissions"));
+            assertEquals(java.util.List.of("ProtocolLib"), metadata.get("depend"));
         } catch (java.io.IOException exception) {
             throw new AssertionError(exception);
         }

src/test/java/games/dmg/spigotstealth/ProtocolLibIdentityMaskingListenerTest.java

@@ -0,0 +1,63 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.utility.MinecraftReflection;
+import com.comphenix.protocol.utility.MinecraftVersion;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
+import org.bukkit.plugin.Plugin;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedStatic;
+
+class ProtocolLibIdentityMaskingListenerTest {
+    private static MockedStatic<MinecraftReflection> reflection;
+
+    @BeforeAll
+    static void initializeProtocolTypesWithoutServer() {
+        MinecraftVersion.setCurrentVersion(new MinecraftVersion(1, 21, 8));
+        reflection = mockStatic(MinecraftReflection.class);
+    }
+
+    @AfterAll
+    static void resetProtocolEnvironment() {
+        reflection.close();
+        MinecraftVersion.setCurrentVersion(null);
+    }
+
+    @Test
+    void skipsPacketWorkWhenNobodyIsConcealed() {
+        AtomicReference<Set<String>> names = new AtomicReference<>(Set.of());
+        var listener = new ProtocolLibIdentityMaskingListener(mock(Plugin.class), names::get, ignored -> { });
+        PacketEvent event = mock(PacketEvent.class);
+        listener.onPacketSending(event);
+        verify(event, never()).getPacket();
+        assertTrue(listener.getSendingWhitelist().getTypes().contains(PacketType.Play.Server.CHAT));
+        assertTrue(listener.getSendingWhitelist().getTypes().contains(PacketType.Play.Server.SYSTEM_CHAT));
+    }
+
+    @Test
+    void readsFreshSnapshotAndWarnsOnceWithoutCancellingOrReplacingFailedPacket() {
+        List<String> warnings = new ArrayList<>();
+        AtomicReference<Set<String>> names = new AtomicReference<>(Set.of());
+        var listener = new ProtocolLibIdentityMaskingListener(mock(Plugin.class), names::get, warnings::add);
+        PacketEvent event = mock(PacketEvent.class);
+        when(event.getPacketType()).thenReturn(PacketType.Play.Server.CHAT);
+        listener.onPacketSending(event);
+        assertTrue(warnings.isEmpty());
+        names.set(Set.of("Secret"));
+        // No real NMS packet: the clone attempt fails and must leave event delivery untouched.
+        listener.onPacketSending(event);
+        listener.onPacketSending(event);
+        assertEquals(1, warnings.size());
+        verify(event, never()).setPacket(any());
+        verify(event, never()).setCancelled(anyBoolean());
+    }
+}

src/test/java/games/dmg/spigotstealth/QualifyingInvisibilityServiceTest.java

@@ -0,0 +1,80 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Map;
+import java.util.UUID;
+import java.util.concurrent.atomic.AtomicLong;
+import org.junit.jupiter.api.Test;
+
+class QualifyingInvisibilityServiceTest {
+    @Test
+    void accumulatesMonotonicElapsedTimeAcrossQualifyingIntervals() {
+        AtomicLong nanos = new AtomicLong();
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            QualifyingInvisibilityService service = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), nanos::get, ignored -> { });
+
+            service.begin(playerId, "Alex", Instant.parse("2026-08-14T10:00:00Z"));
+            nanos.addAndGet(Duration.ofMinutes(3).toNanos());
+            service.stop(playerId).join();
+            service.begin(playerId, "Alex", Instant.parse("2026-08-14T11:00:00Z"));
+            nanos.addAndGet(Duration.ofMinutes(2).toNanos());
+            service.stop(playerId).join();
+
+            assertEquals(Duration.ofMinutes(5).toMillis(), manager.snapshot().player(playerId).accumulatedMillis());
+            assertFalse(service.isQualifying(playerId));
+        }
+    }
+
+    @Test
+    void refreshSettlesExistingIntervalWithoutDoubleCounting() {
+        AtomicLong nanos = new AtomicLong();
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            QualifyingInvisibilityService service = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), nanos::get, ignored -> { });
+            service.begin(playerId, "Alex", Instant.EPOCH);
+            nanos.addAndGet(Duration.ofSeconds(5).toNanos());
+            service.begin(playerId, "Alex", Instant.EPOCH.plusSeconds(5)).join();
+            nanos.addAndGet(Duration.ofSeconds(5).toNanos());
+            service.stop(playerId).join();
+            assertEquals(Duration.ofSeconds(10).toMillis(), manager.snapshot().player(playerId).accumulatedMillis());
+        }
+    }
+
+    @Test
+    void unlocksAndNotifiesExactlyOnceWhilePreservingExcessTime() {
+        AtomicLong nanos = new AtomicLong();
+        UUID playerId = UUID.randomUUID();
+        ArrayList<UUID> notifications = new ArrayList<>();
+        try (StealthStateManager manager = manager()) {
+            QualifyingInvisibilityService service = new QualifyingInvisibilityService(
+                    manager, Duration.ofSeconds(10), nanos::get, notifications::add);
+            service.begin(playerId, "Alex", Instant.EPOCH);
+            nanos.addAndGet(Duration.ofSeconds(11).toNanos());
+            service.checkpoint(playerId).join();
+            nanos.addAndGet(Duration.ofSeconds(2).toNanos());
+            service.stop(playerId).join();
+
+            PlayerStealthState player = manager.snapshot().player(playerId);
+            assertTrue(player.unlocked());
+            assertEquals(Duration.ofSeconds(13).toMillis(), player.accumulatedMillis());
+            assertEquals(java.util.List.of(playerId), notifications);
+        }
+    }
+
+    private static StealthStateManager manager() {
+        StealthStateRepository repository = new StealthStateRepository() {
+            @Override public PersistentStealthState load() { return new PersistentStealthState(Map.of(), Map.of()); }
+            @Override public void save(PersistentStealthState state) { }
+        };
+        return new StealthStateManager(repository, new PersistentStealthState(Map.of(), Map.of()));
+    }
+}

src/test/java/games/dmg/spigotstealth/ServerListPingListenerTest.java

@@ -0,0 +1,36 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.UUID;
+import org.bukkit.entity.Player;
+import org.bukkit.event.server.ServerListPingEvent;
+import org.junit.jupiter.api.Test;
+
+class ServerListPingListenerTest {
+    @Test
+    void removesOnlyConcealedPlayersFromNativeServerPingSample() {
+        UUID concealedId = UUID.randomUUID();
+        Player visible = player(UUID.randomUUID());
+        Player concealed = player(concealedId);
+        ArrayList<Player> sample = new ArrayList<>(List.of(visible, concealed));
+        ServerListPingEvent event = mock(ServerListPingEvent.class);
+        when(event.iterator()).thenReturn(sample.iterator());
+        ServerListPingListener listener = new ServerListPingListener(() -> Set.of(concealedId));
+
+        listener.onServerListPing(event);
+
+        assertEquals(List.of(visible), sample);
+    }
+
+    private static Player player(UUID playerId) {
+        Player player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(playerId);
+        return player;
+    }
+}

src/test/java/games/dmg/spigotstealth/ServerListPingVisibilityTest.java

@@ -0,0 +1,43 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.Set;
+import java.util.UUID;
+import org.junit.jupiter.api.Test;
+
+class ServerListPingVisibilityTest {
+    @Test
+    void publicPlayerCountNeverBecomesNegative() {
+        ServerListPingVisibility.Snapshot adjusted = ServerListPingVisibility.adjust(
+                0, 100, List.of(), Set.of(UUID.randomUUID()));
+
+        assertEquals(0, adjusted.playersOnline());
+    }
+
+    @Test
+    void ordinaryPlayersRemainCountedAndSampled() {
+        UUID firstId = UUID.randomUUID();
+        UUID secondId = UUID.randomUUID();
+
+        ServerListPingVisibility.Snapshot adjusted = ServerListPingVisibility.adjust(
+                2, 100, List.of(firstId, secondId), Set.of());
+
+        assertEquals(2, adjusted.playersOnline());
+        assertEquals(List.of(firstId, secondId), adjusted.samplePlayerIds());
+    }
+
+    @Test
+    void excludesConcealedPlayersFromPublicCountAndSampleWithoutChangingMaximum() {
+        UUID visibleId = UUID.randomUUID();
+        UUID concealedId = UUID.randomUUID();
+
+        ServerListPingVisibility.Snapshot adjusted = ServerListPingVisibility.adjust(
+                2, 100, List.of(visibleId, concealedId), Set.of(concealedId));
+
+        assertEquals(1, adjusted.playersOnline());
+        assertEquals(100, adjusted.playersMaximum());
+        assertEquals(List.of(visibleId), adjusted.samplePlayerIds());
+    }
+}

src/test/java/games/dmg/spigotstealth/ServerPingCompatibilityGuardTest.java

@@ -0,0 +1,24 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+import java.util.ArrayList;
+import org.junit.jupiter.api.Test;
+
+class ServerPingCompatibilityGuardTest {
+    @Test
+    void compatibilityFailureLeavesPingHandlingUsableAndWarnsOnlyOnce() {
+        ArrayList<String> warnings = new ArrayList<>();
+        ServerPingCompatibilityGuard guard = new ServerPingCompatibilityGuard(warnings::add);
+
+        assertDoesNotThrow(() -> guard.run(() -> {
+            throw new IllegalArgumentException("unsupported profile representation");
+        }));
+        assertDoesNotThrow(() -> guard.run(() -> {
+            throw new IllegalArgumentException("unsupported profile representation");
+        }));
+
+        assertEquals(1, warnings.size());
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthAdminCommandTest.java

@@ -0,0 +1,182 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.ArgumentMatchers.contains;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.junit.jupiter.api.Test;
+
+class StealthAdminCommandTest {
+    @Test
+    void completesAdministrativeOperationsByPrefix() {
+        UUID playerId = UUID.randomUUID();
+        try (Fixture fixture = fixture(playerId)) {
+            assertEquals(
+                    List.of("grant"),
+                    fixture.command.onTabComplete(
+                            sender(true), mock(Command.class), "stealthadmin", new String[] {"gr"}));
+            assertEquals(
+                    List.of("status", "grant", "reset", "list", "sleepcount"),
+                    fixture.command.onTabComplete(
+                            sender(true), mock(Command.class), "stealthadmin", new String[] {""}));
+        }
+    }
+
+    @Test
+    void completesContextualArgumentsAndSuppressesIrrelevantSuggestions() {
+        UUID playerId = UUID.randomUUID();
+        try (Fixture fixture = fixture(playerId)) {
+            Command command = mock(Command.class);
+            CommandSender administrator = sender(true);
+
+            assertEquals(
+                    List.of("Alex"),
+                    fixture.command.onTabComplete(
+                            administrator, command, "stealthadmin", new String[] {"status", "al"}));
+            assertEquals(
+                    List.of("confirm"),
+                    fixture.command.onTabComplete(
+                            administrator, command, "stealthadmin", new String[] {"reset", "Alex", "co"}));
+            assertEquals(
+                    List.of("unlocked"),
+                    fixture.command.onTabComplete(
+                            administrator, command, "stealthadmin", new String[] {"list", "un"}));
+            assertEquals(
+                    List.of("status", "include", "exclude"),
+                    fixture.command.onTabComplete(
+                            administrator, command, "stealthadmin", new String[] {"sleepcount", ""}));
+            assertEquals(
+                    List.of(),
+                    fixture.command.onTabComplete(
+                            administrator, command, "stealthadmin", new String[] {"status", "Alex", ""}));
+            assertEquals(
+                    List.of(),
+                    fixture.command.onTabComplete(
+                            sender(false), command, "stealthadmin", new String[] {""}));
+        }
+    }
+
+    @Test
+    void reportsAndChangesPersistentSleepCountPolicyWithImmediateRefreshAndAudit() {
+        UUID playerId = UUID.randomUUID();
+        try (Fixture fixture = fixture(playerId)) {
+            CommandSender sender = sender(true);
+            Command command = mock(Command.class);
+
+            fixture.command.onCommand(
+                    sender, command, "stealthadmin", new String[] {"sleepcount", "status"});
+            verify(sender).sendMessage(contains("excluded"));
+
+            fixture.command.onCommand(
+                    sender, command, "stealthadmin", new String[] {"sleepcount", "include"});
+
+            verify(sender, org.mockito.Mockito.timeout(1000)).sendMessage(contains("now included"));
+            assertEquals(SleepCountPolicy.INCLUDE, fixture.manager.snapshot().sleepCountPolicy());
+            verify(fixture.presentation).refreshSleepCountPolicy();
+            org.junit.jupiter.api.Assertions.assertTrue(fixture.audit.stream()
+                    .anyMatch(message -> message.contains("sleepcount") && message.contains("include")));
+        }
+    }
+
+    @Test
+    void statusInspectsKnownOfflinePlayerAndReportsAllState() {
+        UUID playerId = UUID.randomUUID();
+        try (Fixture fixture = fixture(playerId)) {
+            CommandSender sender = sender(true);
+            fixture.command.onCommand(sender, mock(Command.class), "stealthadmin", new String[] {"status", "Alex"});
+            verify(sender).sendMessage(contains(playerId.toString()));
+            verify(sender).sendMessage(contains("prepared=yes"));
+            verify(sender).sendMessage(contains("concealed=no"));
+        }
+    }
+
+    @Test
+    void listsUnlockedPlayersAndClearlyReportsWhenThereAreNone() {
+        UUID playerId = UUID.randomUUID();
+        try (Fixture fixture = fixture(playerId)) {
+            Command command = mock(Command.class);
+            CommandSender emptySender = sender(true);
+            fixture.command.onCommand(
+                    emptySender, command, "stealthadmin", new String[] {"list", "unlocked"});
+            verify(emptySender).sendMessage("No players have unlocked stealth.");
+
+            fixture.manager.update(state -> state.withPlayer(
+                    state.player(playerId).withProgress(5000L, true))).join();
+            CommandSender populatedSender = sender(true);
+            fixture.command.onCommand(
+                    populatedSender, command, "stealthadmin", new String[] {"list", "unlocked"});
+            verify(populatedSender).sendMessage("Stealth unlocked: Alex");
+        }
+    }
+
+    @Test
+    void grantPersistsThenReportsAndAuditsAction() {
+        UUID playerId = UUID.randomUUID();
+        try (Fixture fixture = fixture(playerId)) {
+            CommandSender sender = sender(true);
+            fixture.command.onCommand(sender, mock(Command.class), "stealthadmin", new String[] {"grant", playerId.toString()});
+            verify(sender, org.mockito.Mockito.timeout(1000)).sendMessage(contains("granted"));
+            org.junit.jupiter.api.Assertions.assertTrue(fixture.manager.snapshot().player(playerId).unlocked());
+            org.junit.jupiter.api.Assertions.assertTrue(fixture.audit.stream().anyMatch(message -> message.contains("grant") && message.contains(playerId.toString())));
+        }
+    }
+
+    @Test
+    void resetRequiresConfirmationAndPermission() {
+        UUID playerId = UUID.randomUUID();
+        try (Fixture fixture = fixture(playerId)) {
+            CommandSender denied = sender(false);
+            fixture.command.onCommand(denied, mock(Command.class), "stealthadmin", new String[] {"reset", "Alex", "confirm"});
+            verify(denied).sendMessage(contains("permission"));
+            CommandSender allowed = sender(true);
+            fixture.command.onCommand(allowed, mock(Command.class), "stealthadmin", new String[] {"reset", "Alex"});
+            verify(allowed).sendMessage(contains("confirm"));
+            verify(allowed, never()).sendMessage(contains("reset complete"));
+        }
+    }
+
+    private static CommandSender sender(boolean permission) {
+        CommandSender sender = mock(CommandSender.class);
+        when(sender.hasPermission("spigotstealth.admin")).thenReturn(permission);
+        when(sender.getName()).thenReturn("Operator");
+        return sender;
+    }
+
+    private static Fixture fixture(UUID playerId) {
+        StealthStateRepository repository = new StealthStateRepository() {
+            @Override public PersistentStealthState load() { return new PersistentStealthState(Map.of(), Map.of()); }
+            @Override public void save(PersistentStealthState state) { }
+        };
+        StealthStateManager manager = new StealthStateManager(repository, new PersistentStealthState(Map.of(), Map.of()));
+        PlayerStealthState player = new PlayerStealthState(playerId, "Alex", 5000L, false, true, false, null, Map.of());
+        manager.update(state -> state.withPlayer(player)).join();
+        QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+        IdentityPresentation presentation = mock(IdentityPresentation.class);
+        StealthAdministrationService administration = new StealthAdministrationService(
+                manager, progression, presentation, ignored -> { }, List::of);
+        KnownPlayerResolver resolver = new KnownPlayerResolver(manager::snapshot, List::of);
+        ArrayList<String> audit = new ArrayList<>();
+        StealthAdminCommand command = new StealthAdminCommand(
+                administration, resolver, Runnable::run, audit::add, Duration.ofHours(8));
+        return new Fixture(manager, command, presentation, audit);
+    }
+
+    private record Fixture(
+            StealthStateManager manager,
+            StealthAdminCommand command,
+            IdentityPresentation presentation,
+            ArrayList<String> audit) implements AutoCloseable {
+        @Override public void close() { manager.close(); }
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthAdminJoinListenerTest.java

@@ -0,0 +1,83 @@
+package games.dmg.spigotstealth;
+
+import static org.mockito.Mockito.*;
+
+import java.util.List;
+import java.util.Set;
+import java.util.UUID;
+import org.bukkit.entity.Player;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.junit.jupiter.api.Test;
+
+class StealthAdminJoinListenerTest {
+    @Test
+    void joiningAdminReceivesCountButExistingAdminsDoNotReceiveOrdinaryJoinNotice() {
+        Player joining = player(true);
+        Player existing = player(true);
+        StealthSessionService sessions = sessions(Set.of(UUID.randomUUID(), UUID.randomUUID()));
+        new StealthAdminJoinListener(sessions, () -> List.of(joining, existing)).onJoin(event(joining));
+        verify(joining).sendMessage("[Stealth] 2 players are invisible. Use /stealthadmin list to see who.");
+        verify(existing, never()).sendMessage(anyString());
+    }
+
+    @Test
+    void concealedJoinNotifiesOnlyAdminsWithUpdatedCount() {
+        Player joining = player(false);
+        Player admin = player(true);
+        Player ordinary = player(false);
+        StealthSessionService sessions = sessions(Set.of(joining.getUniqueId()));
+        new StealthAdminJoinListener(sessions, () -> List.of(joining, admin, ordinary)).onJoin(event(joining));
+        verify(admin).sendMessage("[Stealth] An invisible player joined. 1 player is now invisible. Use /stealthadmin list to see who.");
+        verify(joining, never()).sendMessage(anyString());
+        verify(ordinary, never()).sendMessage(anyString());
+    }
+
+    @Test
+    void concealedAdminGetsExactlyOneNoticeEvenWhenIncludedInOnlinePlayers() {
+        Player joining = player(true);
+        Player admin = player(true);
+        StealthSessionService sessions = sessions(Set.of(joining.getUniqueId(), UUID.randomUUID()));
+        new StealthAdminJoinListener(sessions, () -> List.of(joining, admin)).onJoin(event(joining));
+        verify(joining, times(1)).sendMessage("[Stealth] 2 players are invisible. Use /stealthadmin list to see who.");
+        verify(admin).sendMessage("[Stealth] An invisible player joined. 2 players are now invisible. Use /stealthadmin list to see who.");
+    }
+
+    @Test
+    void zeroCountIsSilent() {
+        Player joining = player(true);
+        new StealthAdminJoinListener(sessions(Set.of()), () -> List.of(joining)).onJoin(event(joining));
+        verify(joining, never()).sendMessage(anyString());
+    }
+
+    @Test
+    void ordinaryJoinIsSilentAndSinglePlayerCountUsesSingular() {
+        Player ordinary = player(false);
+        Player admin = player(true);
+        StealthAdminJoinListener listener = new StealthAdminJoinListener(
+                sessions(Set.of(UUID.randomUUID())), () -> List.of(ordinary, admin));
+        listener.onJoin(event(ordinary));
+        verify(ordinary, never()).sendMessage(anyString());
+        verify(admin, never()).sendMessage(anyString());
+        listener.onJoin(event(admin));
+        verify(admin).sendMessage("[Stealth] 1 player is invisible. Use /stealthadmin list to see who.");
+    }
+
+    private static StealthSessionService sessions(Set<UUID> ids) {
+        StealthSessionService sessions = mock(StealthSessionService.class);
+        when(sessions.concealedPlayerIds()).thenReturn(ids);
+        return sessions;
+    }
+
+    private static Player player(boolean admin) {
+        Player player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(UUID.randomUUID());
+        when(player.hasPermission("spigotstealth.admin")).thenReturn(admin);
+        return player;
+    }
+
+    private static PlayerJoinEvent event(Player player) {
+        PlayerJoinEvent event = mock(PlayerJoinEvent.class);
+        when(event.getPlayer()).thenReturn(player);
+        return event;
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthAdministrationServiceTest.java

@@ -0,0 +1,136 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import org.bukkit.entity.Player;
+import org.junit.jupiter.api.Test;
+
+class StealthAdministrationServiceTest {
+    @Test
+    void persistsSleepCountPolicyChangesIdempotently() {
+        try (StealthStateManager manager = manager()) {
+            StealthAdministrationService administration = service(manager, List::of, ignored -> { });
+
+            assertEquals(SleepCountPolicy.EXCLUDE, administration.sleepCountPolicy());
+            assertTrue(administration.setSleepCountPolicy(SleepCountPolicy.INCLUDE).join().changed());
+            assertEquals(SleepCountPolicy.INCLUDE, manager.snapshot().sleepCountPolicy());
+            assertFalse(administration.setSleepCountPolicy(SleepCountPolicy.INCLUDE).join().changed());
+        }
+    }
+
+    @Test
+    void grantsOfflineUnlockAndNotifiesExactlyOnce() {
+        UUID playerId = UUID.randomUUID();
+        ArrayList<UUID> notifications = new ArrayList<>();
+        try (StealthStateManager manager = manager()) {
+            StealthAdministrationService administration = service(manager, List::of, notifications::add);
+            assertTrue(administration.grant(playerId, "Alex").join().changed());
+            assertFalse(administration.grant(playerId, "Alex").join().changed());
+            assertTrue(manager.snapshot().player(playerId).unlocked());
+            assertEquals(List.of(playerId), notifications);
+        }
+    }
+
+    @Test
+    void resetClearsProgressUnlockPreparationConcealmentAndActiveTracking() {
+        UUID playerId = UUID.randomUUID();
+        Player player = mock(Player.class);
+        org.mockito.Mockito.when(player.getUniqueId()).thenReturn(playerId);
+        try (StealthStateManager manager = manager()) {
+            PlayerStealthState state = new PlayerStealthState(
+                    playerId, "Alex", 1234L, true, true, true, Instant.EPOCH, Map.of("future", "keep"));
+            manager.update(all -> all.withPlayer(state)).join();
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            progression.begin(playerId, "Alex", Instant.EPOCH).join();
+            IdentityPresentation presentation = mock(IdentityPresentation.class);
+            StealthAdministrationService administration = new StealthAdministrationService(
+                    manager, progression, presentation, ignored -> { }, () -> List.of(player));
+
+            administration.reset(playerId, "Alex", player).join();
+
+            PlayerStealthState reset = manager.snapshot().player(playerId);
+            assertEquals(0L, reset.accumulatedMillis());
+            assertFalse(reset.unlocked());
+            assertFalse(reset.preparedLogin());
+            assertFalse(reset.concealed());
+            assertFalse(progression.isQualifying(playerId));
+            assertEquals("keep", reset.unknownFields().get("future"));
+            verify(presentation).reveal(player);
+        }
+    }
+
+    @Test
+    void listsAllUnlockedPlayersByNameOrUuidInCaseInsensitiveOrder() {
+        UUID namelessId = UUID.randomUUID();
+        UUID lockedId = UUID.randomUUID();
+        UUID zoeId = UUID.randomUUID();
+        UUID alexId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            manager.update(state -> state
+                    .withPlayer(PlayerStealthState.empty(namelessId).withProgress(0L, true))
+                    .withPlayer(PlayerStealthState.empty(lockedId).withLastKnownName("Locked"))
+                    .withPlayer(PlayerStealthState.empty(zoeId).withLastKnownName("zoe").withProgress(1L, true))
+                    .withPlayer(PlayerStealthState.empty(alexId).withLastKnownName("Alex").withProgress(2L, true)))
+                    .join();
+            StealthAdministrationService administration = service(manager, List::of, ignored -> { });
+
+            assertEquals(
+                    List.of("Alex", namelessId.toString(), "zoe").stream()
+                            .sorted(String.CASE_INSENSITIVE_ORDER)
+                            .toList(),
+                    administration.unlockedPlayerNames());
+        }
+    }
+
+    @Test
+    void listsOnlyCurrentlyOnlineConcealedPlayers() {
+        UUID concealedId = UUID.randomUUID();
+        UUID ordinaryId = UUID.randomUUID();
+        Player concealed = player(concealedId, "Hidden");
+        Player ordinary = player(ordinaryId, "Visible");
+        try (StealthStateManager manager = manager()) {
+            manager.update(state -> state
+                    .withPlayer(PlayerStealthState.empty(concealedId).withLastKnownName("Hidden").withSession(false, true))
+                    .withPlayer(PlayerStealthState.empty(ordinaryId).withLastKnownName("Visible"))).join();
+            StealthAdministrationService administration = service(
+                    manager, () -> List.of(concealed, ordinary), ignored -> { });
+            assertEquals(List.of("Hidden"), administration.concealedOnlineNames());
+        }
+    }
+
+    private static StealthAdministrationService service(
+            StealthStateManager manager,
+            java.util.function.Supplier<? extends java.util.Collection<? extends Player>> online,
+            java.util.function.Consumer<UUID> notifier) {
+        QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+        return new StealthAdministrationService(
+                manager, progression, mock(IdentityPresentation.class), notifier, online);
+    }
+
+    private static Player player(UUID playerId, String name) {
+        Player player = mock(Player.class);
+        org.mockito.Mockito.when(player.getUniqueId()).thenReturn(playerId);
+        org.mockito.Mockito.when(player.getName()).thenReturn(name);
+        return player;
+    }
+
+    private static StealthStateManager manager() {
+        StealthStateRepository repository = new StealthStateRepository() {
+            @Override public PersistentStealthState load() { return new PersistentStealthState(Map.of(), Map.of()); }
+            @Override public void save(PersistentStealthState state) { }
+        };
+        return new StealthStateManager(repository, new PersistentStealthState(Map.of(), Map.of()));
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthChatMaskerTest.java

@@ -0,0 +1,70 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.google.gson.JsonParser;
+import java.util.Set;
+import org.junit.jupiter.api.Test;
+
+class StealthChatMaskerTest {
+    private final StealthChatMasker masker = new StealthChatMasker(Set.of("Secret"));
+
+    @Test
+    void masksSenderAndRemovesIdentityMetadataWithoutChangingMessage() {
+        String input = """
+                {"translate":"chat.type.text","with":[
+                  {"text":"Secret","hoverEvent":{"action":"show_entity","contents":{"name":"Secret"}},
+                   "clickEvent":{"action":"suggest_command","value":"/msg Secret "}},
+                  {"text":"Secret says hello","clickEvent":{"action":"copy_to_clipboard","value":"Secret"}}]}
+                """;
+        var result = JsonParser.parseString(masker.maskAnnouncement(input)).getAsJsonObject();
+        var args = result.getAsJsonArray("with");
+        assertEquals(JsonParser.parseString("{\"text\":\"Anonymous\",\"obfuscated\":true,\"hoverEvent\":null,\"clickEvent\":null,\"insertion\":\"\"}"), args.get(0));
+        assertEquals(JsonParser.parseString(input).getAsJsonObject().getAsJsonArray("with").get(1), args.get(1));
+    }
+
+    @Test
+    void handlesPrivateMessagesAndAdvancementNamesOnly() {
+        for (String key : Set.of("commands.message.display.incoming", "commands.message.display.outgoing",
+                "chat.type.advancement.task", "chat.type.advancement.goal", "chat.type.advancement.challenge")) {
+            String input = "{\"translate\":\"" + key + "\",\"with\":[\"secret\",{\"text\":\"Secret\"}]}";
+            var args = JsonParser.parseString(masker.maskAnnouncement(input)).getAsJsonObject().getAsJsonArray("with");
+            assertEquals("Anonymous", args.get(0).getAsJsonObject().get("text").getAsString());
+            assertEquals("Secret", args.get(1).getAsJsonObject().get("text").getAsString());
+        }
+    }
+
+    @Test
+    void doesNotTraverseMessageBodyEvenWhenItContainsChatTranslations() {
+        String input = """
+                {"translate":"chat.type.text","with":["Ordinary",
+                  {"translate":"chat.type.text","with":["Secret","body"]}]}
+                """;
+        assertEquals(input, masker.maskAnnouncement(input));
+    }
+
+    @Test
+    void handlesNestedAnnouncementsButNotPlainTextOrUnknownTranslations() {
+        assertTrue(masker.maskAnnouncement("{\"text\":\"\",\"extra\":[{\"translate\":\"chat.type.text\",\"with\":[\"Secret\",\"hello\"]}]}").contains("Anonymous"));
+        for (String input : Set.of("{\"text\":\"Secret: hello\"}", "{\"translate\":\"custom\",\"with\":[\"Secret\"]}", "not json")) {
+            assertEquals(input, masker.maskAnnouncement(input));
+        }
+    }
+
+    @Test
+    void removesInheritedActionsFromArrayParent() {
+        String json = """
+                [{"text":"","hover_event":{"action":"show_text","value":"Secret"}},
+                 {"translate":"chat.type.text","with":["Secret","hello"]}]
+                """;
+        assertFalse(masker.maskAnnouncement(json).contains("Secret"));
+    }
+
+    @Test
+    void recognizesSplitNamesAndMasksWholeNameComponent() {
+        String name = "{\"text\":\"Sec\",\"extra\":[{\"text\":\"ret\"}],\"insertion\":\"Secret\"}";
+        assertTrue(masker.maskDisplayName(name).contains("Anonymous"));
+        assertFalse(masker.maskDisplayName(name).contains("Secret"));
+        assertEquals("\"NotSecret\"", masker.maskDisplayName("\"NotSecret\""));
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthCommandTest.java

@@ -0,0 +1,88 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.contains;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import java.util.concurrent.atomic.AtomicLong;
+import org.bukkit.command.Command;
+import org.bukkit.entity.Player;
+import org.junit.jupiter.api.Test;
+
+class StealthCommandTest {
+    @Test
+    void completesProgressByPrefixWithoutSuggestingPlayersElsewhere() {
+        try (StealthStateManager manager = manager()) {
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            StealthCommand command = new StealthCommand(manager, progression, StealthSettings.from(Map.of()));
+            Command bukkitCommand = mock(Command.class);
+            Player player = player(UUID.randomUUID());
+
+            org.junit.jupiter.api.Assertions.assertEquals(
+                    List.of("progress"),
+                    command.onTabComplete(player, bukkitCommand, "stealth", new String[] {"pr"}));
+            org.junit.jupiter.api.Assertions.assertEquals(
+                    List.of(),
+                    command.onTabComplete(player, bukkitCommand, "stealth", new String[] {"progress", ""}));
+        }
+    }
+
+    @Test
+    void reportsLiveProgressTargetAndRemainingTimeWithoutMutatingState() {
+        UUID playerId = UUID.randomUUID();
+        AtomicLong nanos = new AtomicLong();
+        try (StealthStateManager manager = manager()) {
+            manager.update(state -> state.withPlayer(state.player(playerId).withAccumulatedMillis(Duration.ofHours(2).toMillis()))).join();
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), nanos::get, ignored -> { });
+            progression.begin(playerId, "Alex", Instant.EPOCH).join();
+            nanos.addAndGet(Duration.ofMinutes(5).toNanos());
+            Player player = player(playerId);
+            StealthCommand command = new StealthCommand(manager, progression, StealthSettings.from(Map.of()));
+
+            assertTrue(command.onCommand(player, mock(Command.class), "stealth", new String[] {"progress"}));
+            verify(player).sendMessage(contains("2h 5m / 8h"));
+            verify(player).sendMessage(contains("5h 55m remaining"));
+            org.junit.jupiter.api.Assertions.assertEquals(Duration.ofHours(2).toMillis(), manager.snapshot().player(playerId).accumulatedMillis());
+        }
+    }
+
+    @Test
+    void unlockedPlayerReceivesUsageGuidance() {
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            PlayerStealthState unlocked = new PlayerStealthState(playerId, "Alex", Duration.ofHours(8).toMillis(), true, false, false, null, Map.of());
+            manager.update(state -> state.withPlayer(unlocked)).join();
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            Player player = player(playerId);
+            StealthCommand command = new StealthCommand(manager, progression, StealthSettings.from(Map.of()));
+
+            command.onCommand(player, mock(Command.class), "stealth", new String[] {"progress"});
+            verify(player).sendMessage(contains("unlocked"));
+            verify(player).sendMessage(contains("log out while invisible"));
+        }
+    }
+
+    private static Player player(UUID playerId) {
+        Player player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(playerId);
+        return player;
+    }
+
+    private static StealthStateManager manager() {
+        StealthStateRepository repository = new StealthStateRepository() {
+            @Override public PersistentStealthState load() { return new PersistentStealthState(Map.of(), Map.of()); }
+            @Override public void save(PersistentStealthState state) { }
+        };
+        return new StealthStateManager(repository, new PersistentStealthState(Map.of(), Map.of()));
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthProgressFormatterTest.java

@@ -0,0 +1,15 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.time.Duration;
+import org.junit.jupiter.api.Test;
+
+class StealthProgressFormatterTest {
+    @Test
+    void presentsConciseHumanReadableDurations() {
+        assertEquals("2h 5m 9s", StealthProgressFormatter.duration(Duration.ofHours(2).plusMinutes(5).plusSeconds(9).toMillis()));
+        assertEquals("45s", StealthProgressFormatter.duration(45_900L));
+        assertEquals("0s", StealthProgressFormatter.duration(0L));
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthSessionListenerTest.java

@@ -0,0 +1,123 @@
+package games.dmg.spigotstealth;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.time.Duration;
+import java.util.Map;
+import java.util.UUID;
+import org.bukkit.entity.Player;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.event.player.PlayerQuitEvent;
+import org.junit.jupiter.api.Test;
+
+class StealthSessionListenerTest {
+    @Test
+    void concealedDisconnectSuppressesPublicAnnouncementBeforeCleanup() {
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            manager.update(state -> state.withPlayer(unlocked(playerId).withSession(false, true))).join();
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            StealthSessionService sessions = new StealthSessionService(manager, progression);
+            StealthSessionListener listener = new StealthSessionListener(
+                    sessions, mock(IdentityPresentation.class), "Stealth active");
+            PlayerQuitEvent event = mock(PlayerQuitEvent.class);
+            Player player = player(playerId);
+            when(event.getPlayer()).thenReturn(player);
+
+            listener.onQuit(event);
+
+            verify(event).setQuitMessage(null);
+        }
+    }
+
+    @Test
+    void ordinaryDisconnectRetainsPublicAnnouncement() {
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            StealthSessionListener listener = new StealthSessionListener(
+                    new StealthSessionService(manager, progression),
+                    mock(IdentityPresentation.class),
+                    "Stealth active");
+            PlayerQuitEvent event = mock(PlayerQuitEvent.class);
+            Player player = player(playerId);
+            when(event.getPlayer()).thenReturn(player);
+
+            listener.onQuit(event);
+
+            verify(event, never()).setQuitMessage(null);
+        }
+    }
+
+    @Test
+    void preparedLoginSuppressesAnnouncementAndConcealsIdentityForSession() {
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            manager.update(state -> state.withPlayer(unlocked(playerId).withSession(true, false))).join();
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            IdentityPresentation presentation = mock(IdentityPresentation.class);
+            StealthSessionService sessions = new StealthSessionService(manager, progression);
+            StealthSessionListener listener = new StealthSessionListener(
+                    sessions, presentation, "Stealth active");
+            Player player = player(playerId);
+            PlayerJoinEvent event = mock(PlayerJoinEvent.class);
+            when(event.getPlayer()).thenReturn(player);
+
+            listener.onJoin(event);
+
+            verify(event).setJoinMessage(null);
+            verify(presentation).conceal(player);
+            verify(player).sendMessage("Stealth active");
+            Player admin = player(UUID.randomUUID());
+            when(admin.hasPermission("spigotstealth.admin")).thenReturn(true);
+            new StealthAdminJoinListener(sessions, () -> java.util.List.of(player, admin)).onJoin(event);
+            verify(admin).sendMessage("[Stealth] An invisible player joined. 1 player is now invisible. Use /stealthadmin list to see who.");
+        }
+    }
+
+    @Test
+    void ordinaryLoginRetainsAnnouncementAndIdentity() {
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            IdentityPresentation presentation = mock(IdentityPresentation.class);
+            StealthSessionListener listener = new StealthSessionListener(
+                    new StealthSessionService(manager, progression), presentation, "Stealth active");
+            Player player = player(playerId);
+            PlayerJoinEvent event = mock(PlayerJoinEvent.class);
+            when(event.getPlayer()).thenReturn(player);
+
+            listener.onJoin(event);
+
+            verify(event, never()).setJoinMessage(null);
+            verify(presentation).reveal(player);
+            verify(player, never()).sendMessage("Stealth active");
+        }
+    }
+
+    private static Player player(UUID playerId) {
+        Player player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(playerId);
+        when(player.getName()).thenReturn("Alex");
+        return player;
+    }
+
+    private static PlayerStealthState unlocked(UUID playerId) {
+        return new PlayerStealthState(playerId, "Alex", Duration.ofHours(8).toMillis(), true, false, false, null, Map.of());
+    }
+
+    private static StealthStateManager manager() {
+        StealthStateRepository repository = new StealthStateRepository() {
+            @Override public PersistentStealthState load() { return new PersistentStealthState(Map.of(), Map.of()); }
+            @Override public void save(PersistentStealthState state) { }
+        };
+        return new StealthStateManager(repository, new PersistentStealthState(Map.of(), Map.of()));
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthSessionServiceTest.java

@@ -0,0 +1,94 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import org.junit.jupiter.api.Test;
+
+class StealthSessionServiceTest {
+    @Test
+    void reportsOnlyCurrentlyConcealedPlayerIdsForPublicPresentation() {
+        UUID concealedId = UUID.randomUUID();
+        UUID staleId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            manager.update(state -> state
+                    .withPlayer(unlocked(concealedId).withSession(true, false))
+                    .withPlayer(unlocked(staleId).withSession(false, true)))
+                    .join();
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            StealthSessionService sessions = new StealthSessionService(manager, progression);
+            sessions.login(concealedId, "Hidden");
+
+            assertEquals(Set.of(concealedId), sessions.concealedPlayerIds());
+            manager.update(state -> state.withPlayer(
+                    state.player(concealedId).withSession(false, false))).join();
+            assertEquals(Set.of(), sessions.concealedPlayerIds());
+        }
+    }
+
+    @Test
+    void unlockedQualifyingDisconnectPreparesAndConsumesOneConcealedLogin() {
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            manager.update(state -> state.withPlayer(unlocked(playerId))).join();
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            progression.begin(playerId, "Alex", Instant.EPOCH).join();
+            StealthSessionService sessions = new StealthSessionService(manager, progression);
+
+            sessions.disconnect(playerId).join();
+            assertTrue(manager.snapshot().player(playerId).preparedLogin());
+            assertTrue(sessions.login(playerId, "Alex").concealed());
+            assertFalse(manager.snapshot().player(playerId).preparedLogin());
+            assertTrue(manager.snapshot().player(playerId).concealed());
+
+            sessions.disconnect(playerId).join();
+            assertFalse(sessions.login(playerId, "Alex").concealed());
+        }
+    }
+
+    @Test
+    void lockedPlayerCannotPrepareConcealedLogin() {
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            progression.begin(playerId, "Alex", Instant.EPOCH).join();
+            StealthSessionService sessions = new StealthSessionService(manager, progression);
+            sessions.disconnect(playerId).join();
+            assertFalse(sessions.login(playerId, "Alex").concealed());
+        }
+    }
+
+    @Test
+    void ordinaryDisconnectClearsEarlierPreparation() {
+        UUID playerId = UUID.randomUUID();
+        try (StealthStateManager manager = manager()) {
+            manager.update(state -> state.withPlayer(unlocked(playerId).withSession(true, false))).join();
+            QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
+                    manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
+            StealthSessionService sessions = new StealthSessionService(manager, progression);
+            sessions.disconnect(playerId).join();
+            assertFalse(manager.snapshot().player(playerId).preparedLogin());
+        }
+    }
+
+    private static PlayerStealthState unlocked(UUID playerId) {
+        return new PlayerStealthState(playerId, "Alex", Duration.ofHours(8).toMillis(), true, false, false, null, Map.of());
+    }
+
+    private static StealthStateManager manager() {
+        StealthStateRepository repository = new StealthStateRepository() {
+            @Override public PersistentStealthState load() { return new PersistentStealthState(Map.of(), Map.of()); }
+            @Override public void save(PersistentStealthState state) { }
+        };
+        return new StealthStateManager(repository, new PersistentStealthState(Map.of(), Map.of()));
+    }
+}

src/test/java/games/dmg/spigotstealth/YamlStealthStateRepositoryTest.java

@@ -15,15 +15,28 @@ import org.junit.jupiter.api.io.TempDir;
 class YamlStealthStateRepositoryTest {
     @TempDir Path temporaryDirectory;
 
+    @Test
+    void missingOrInvalidSleepCountPolicyDefaultsToExclude() throws Exception {
+        Path missingFile = temporaryDirectory.resolve("missing.yml");
+        YamlStealthStateRepository missing = new YamlStealthStateRepository(missingFile);
+        assertEquals(SleepCountPolicy.EXCLUDE, missing.load().sleepCountPolicy());
+
+        Path invalidFile = temporaryDirectory.resolve("invalid.yml");
+        Files.writeString(invalidFile, "sleep-count-policy: surprise\n");
+        YamlStealthStateRepository invalid = new YamlStealthStateRepository(invalidFile);
+        assertEquals(SleepCountPolicy.EXCLUDE, invalid.load().sleepCountPolicy());
+    }
+
     @Test
     void roundTripsUuidStateAndPreservesUnknownFields() throws Exception {
         UUID playerId = UUID.randomUUID();
         Path stateFile = temporaryDirectory.resolve("state.yml");
-        Files.writeString(stateFile, "schema-version: 1\nfuture-root: keep\nplayers:\n  " + playerId + ":\n    accumulated-millis: 25\n    unlocked: false\n    prepared-login: true\n    concealed: false\n    qualifying-since: '2026-08-14T10:00:00Z'\n    last-known-name: Alex\n    future-player: keep-too\n");
+        Files.writeString(stateFile, "schema-version: 1\nsleep-count-policy: include\nfuture-root: keep\nplayers:\n  " + playerId + ":\n    accumulated-millis: 25\n    unlocked: false\n    prepared-login: true\n    concealed: false\n    qualifying-since: '2026-08-14T10:00:00Z'\n    last-known-name: Alex\n    future-player: keep-too\n");
         YamlStealthStateRepository repository = new YamlStealthStateRepository(stateFile);
 
         PersistentStealthState loaded = repository.load();
         PlayerStealthState player = loaded.player(playerId);
+        assertEquals(SleepCountPolicy.INCLUDE, loaded.sleepCountPolicy());
         assertEquals(25L, player.accumulatedMillis());
         assertTrue(player.preparedLogin());
         assertEquals(Instant.parse("2026-08-14T10:00:00Z"), player.qualifyingSince());
@@ -31,6 +44,7 @@ class YamlStealthStateRepositoryTest {
         repository.save(loaded.withPlayer(player.withAccumulatedMillis(50L)));
         String saved = Files.readString(stateFile);
         assertTrue(saved.contains("future-root: keep"));
+        assertTrue(saved.contains("sleep-count-policy: include"));
         assertTrue(saved.contains("future-player: keep-too"));
         assertEquals(50L, repository.load().player(playerId).accumulatedMillis());
     }