docs(claude): Lesson 26 — jail-at-entry doesn't jail the recursive walk (security review caught what my review missed)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CLAUDE.md

@@ -447,3 +447,5 @@ Things I discovered about myself building a sister platform across multiple sess
 24. **`onModuleInit` runs before async `onModuleInit` of dependencies completes — register NATS/external subscriptions in `onApplicationBootstrap`.** `NatsService.onModuleInit` connects to NATS (async); `NatsBridgeService`/`HostAgentConsumerService` registered their subscriptions in their own `onModuleInit`, which fired while the connection was still null — so every `subscribe()` hit the `[OFFLINE]` no-op path and the WS bridge was dead-on-boot in *every* production build, silently. Nest guarantees `onApplicationBootstrap` runs only after all module init (including the awaited connect) finishes. Anything that depends on another provider's async startup belongs in bootstrap, not init. The tell: a subscription that "should be there" but the handler never fires and there's no error — trace the *startup ordering*, not the handler.
 
 25. **Fixing a dead code path detonates the live code behind it — budget for the second bug.** The moment Lesson 24's fix made the NATS→WS bridge actually deliver events, the API crashed on the first forwarded heartbeat: `WebSocket.OPEN` was `undefined` at runtime because `esModuleInterop` is off, so `import WebSocket from 'ws'` compiled to `ws_1.default` (undefined). That crash had sat behind the dead bridge since the gateway was written — never hit because no event ever reached it. When you resurrect a path that was silently no-op, everything downstream of it is effectively *untested code running for the first time in production*. Verify the whole chain end-to-end (I watched the DB row appear, then flip offline), don't stop at "the subscription fires now." This is Lesson 10 with a fuse on it. Import-runtime gotcha worth remembering: when `esModuleInterop` is off, prefer instance constants (`client.OPEN`) over class statics (`WebSocket.OPEN`) for `ws`.
+
+26. **A jail check at the entry point does not jail the recursive walk behind it — and my own "line-by-line" review missed it; the automated security review didn't.** The file manager's `jail()` correctly canonicalized and prefix-checked the top-level path, and I traced every escape vector through it and signed off. But `copy_recursive` then walked the directory tree with `fs::metadata` (which *follows* symlinks). A symlink planted inside the jail pointing at `/etc`, then a `copy` of its parent, would dereference it and pull external content *into* the jail to be read — a jail escape the entry check never sees, because the escape is reintroduced by a descendant during traversal. Fix: `symlink_metadata` (lstat) everywhere you recurse, and refuse/never-follow symlinks across the boundary. The transferable rule: **validate at the boundary AND at every step that re-derives a path** (recursion, `read_dir`, glob, archive extraction). And the humbling part — I was confident after reviewing the jail function; the security-review pass caught the HIGH I'd waved through. Trust adversarial verification over your own once-over on security-critical code, especially path/traversal logic.

backend-nest/src/app.module.ts

@@ -52,6 +52,8 @@ import { NatsBridgeService } from './services/nats-bridge.service';
 import { HostAgentConsumerService } from './services/host-agent-consumer.service';
 import { ServerConnection } from './entities/server-connection.entity';
 import { License } from './entities/license.entity';
+import { AgentHost } from './entities/agent-host.entity';
+import { GameInstance } from './entities/game-instance.entity';
 import { SteamService } from './services/steam.service';
 
 // Gateway
@@ -95,7 +97,7 @@ import { NatsBridgeGateway } from './gateways/nats-bridge.gateway';
     ScheduleModule.forRoot(),
 
     // Repositories for app-level shared services (host-agent consumer)
-    TypeOrmModule.forFeature([ServerConnection, License]),
+    TypeOrmModule.forFeature([ServerConnection, License, AgentHost, GameInstance]),
 
     // Feature Modules
     AuthModule,

backend-nest/src/entities/agent-host.entity.ts

@@ -0,0 +1,74 @@
+import { Entity, PrimaryGeneratedColumn, Column, ManyToOne, JoinColumn, Check, Unique } from 'typeorm';
+import { License } from './license.entity';
+
+export interface AgentHostDisk {
+  mount: string;
+  total_mb: number;
+  free_mb: number;
+}
+
+/**
+ * One Corrosion host agent / one machine. Owns the machine-level facts.
+ *
+ * NOTE: distinct from the B2B `hosts` table (hosting-partner companies). This
+ * is `agent_hosts` — the physical/virtual box a customer runs the agent on.
+ */
+@Entity('agent_hosts')
+@Unique(['license_id', 'hostname'])
+@Check(`"status" IN ('connected', 'degraded', 'offline')`)
+export class AgentHost {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column({ type: 'uuid' })
+  license_id: string;
+
+  @Column({ type: 'varchar', length: 255, default: '' })
+  hostname: string;
+
+  @Column({ type: 'varchar', length: 64, nullable: true })
+  agent_version: string | null;
+
+  @Column({ type: 'varchar', length: 64, nullable: true })
+  agent_commit: string | null;
+
+  @Column({ type: 'varchar', length: 32, nullable: true })
+  os: string | null;
+
+  @Column({ type: 'varchar', length: 32, nullable: true })
+  arch: string | null;
+
+  @Column({ type: 'varchar', length: 20, default: 'offline' })
+  status: string;
+
+  @Column({ type: 'timestamptz', nullable: true })
+  last_heartbeat_at: Date | null;
+
+  @Column({ type: 'double precision', nullable: true })
+  cpu_percent: number | null;
+
+  @Column({ type: 'integer', nullable: true })
+  cpu_cores: number | null;
+
+  @Column({ type: 'bigint', nullable: true })
+  mem_total_mb: number | null;
+
+  @Column({ type: 'bigint', nullable: true })
+  mem_used_mb: number | null;
+
+  @Column({ type: 'bigint', nullable: true })
+  uptime_seconds: number | null;
+
+  @Column({ type: 'jsonb', nullable: true })
+  disks: AgentHostDisk[] | null;
+
+  @Column({ type: 'timestamptz', default: () => 'NOW()' })
+  created_at: Date;
+
+  @Column({ type: 'timestamptz', default: () => 'NOW()' })
+  updated_at: Date;
+
+  @ManyToOne(() => License, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'license_id' })
+  license: License;
+}

backend-nest/src/entities/game-instance.entity.ts

@@ -0,0 +1,59 @@
+import { Entity, PrimaryGeneratedColumn, Column, ManyToOne, JoinColumn, Unique } from 'typeorm';
+import { License } from './license.entity';
+import { AgentHost } from './agent-host.entity';
+
+/**
+ * One game server process / orchestrated unit (a Rust server, a Conan world,
+ * a Dune battlegroup). The billing unit — plans count instances.
+ * `agent_instance_id` is the agent's slug and the NATS subject segment.
+ */
+@Entity('game_instances')
+@Unique(['license_id', 'agent_instance_id'])
+export class GameInstance {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column({ type: 'uuid' })
+  license_id: string;
+
+  @Column({ type: 'uuid', nullable: true })
+  host_id: string | null;
+
+  @Column({ type: 'uuid', nullable: true })
+  cluster_id: string | null;
+
+  @Column({ type: 'varchar', length: 64 })
+  agent_instance_id: string;
+
+  @Column({ type: 'varchar', length: 32 })
+  game: string;
+
+  @Column({ type: 'varchar', length: 255, nullable: true })
+  label: string | null;
+
+  @Column({ type: 'varchar', length: 32, default: 'unknown' })
+  state: string;
+
+  @Column({ type: 'text', nullable: true })
+  root_path: string | null;
+
+  @Column({ type: 'bigint', default: 0 })
+  uptime_seconds: number;
+
+  @Column({ type: 'timestamptz', nullable: true })
+  last_seen_at: Date | null;
+
+  @Column({ type: 'timestamptz', default: () => 'NOW()' })
+  created_at: Date;
+
+  @Column({ type: 'timestamptz', default: () => 'NOW()' })
+  updated_at: Date;
+
+  @ManyToOne(() => License, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'license_id' })
+  license: License;
+
+  @ManyToOne(() => AgentHost, { onDelete: 'SET NULL', nullable: true })
+  @JoinColumn({ name: 'host_id' })
+  host: AgentHost | null;
+}

backend-nest/src/entities/instance-cluster.entity.ts

@@ -0,0 +1,38 @@
+import { Entity, PrimaryGeneratedColumn, Column, ManyToOne, JoinColumn } from 'typeorm';
+import { License } from './license.entity';
+
+/**
+ * Optional grouping of instances for games with linked topologies:
+ * Soulmask main/child clusters, Dune BattleGroup → Sietches. Reserved now;
+ * cluster orchestration ships with those game adapters.
+ */
+@Entity('instance_clusters')
+export class InstanceCluster {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column({ type: 'uuid' })
+  license_id: string;
+
+  @Column({ type: 'varchar', length: 32 })
+  game: string;
+
+  @Column({ type: 'varchar', length: 255 })
+  name: string;
+
+  @Column({ type: 'varchar', length: 32, nullable: true })
+  topology: string | null;
+
+  @Column({ type: 'jsonb', nullable: true })
+  config: Record<string, unknown> | null;
+
+  @Column({ type: 'timestamptz', default: () => 'NOW()' })
+  created_at: Date;
+
+  @Column({ type: 'timestamptz', default: () => 'NOW()' })
+  updated_at: Date;
+
+  @ManyToOne(() => License, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'license_id' })
+  license: License;
+}

backend-nest/src/entities/instance-stats.entity.ts

@@ -0,0 +1,38 @@
+import { Entity, PrimaryGeneratedColumn, Column, ManyToOne, JoinColumn } from 'typeorm';
+import { GameInstance } from './game-instance.entity';
+
+/**
+ * Per-instance time-series game metrics (player count, FPS, …). Populated once
+ * game-level telemetry is collected via RCON/plugin — the host heartbeat
+ * carries host metrics, not game metrics, so this stays empty in Phase A.
+ */
+@Entity('instance_stats')
+export class InstanceStats {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column({ type: 'uuid' })
+  instance_id: string;
+
+  @Column({ type: 'uuid' })
+  license_id: string;
+
+  @Column({ type: 'integer', default: 0 })
+  player_count: number;
+
+  @Column({ type: 'integer', default: 0 })
+  max_players: number;
+
+  @Column({ type: 'double precision', default: 0 })
+  fps: number;
+
+  @Column({ type: 'integer', default: 0 })
+  memory_usage_mb: number;
+
+  @Column({ type: 'timestamptz', default: () => 'NOW()' })
+  recorded_at: Date;
+
+  @ManyToOne(() => GameInstance, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'instance_id' })
+  instance: GameInstance;
+}

backend-nest/src/services/host-agent-consumer.service.ts

@@ -5,30 +5,53 @@ import { Repository } from 'typeorm';
 import { NatsService } from './nats.service';
 import { ServerConnection } from '../entities/server-connection.entity';
 import { License } from '../entities/license.entity';
+import { AgentHost, AgentHostDisk } from '../entities/agent-host.entity';
+import { GameInstance } from '../entities/game-instance.entity';
 
 /**
  * Consumes Corrosion wire protocol v2 host-agent subjects
- * (corrosion-host-agent/PROTOCOL.md) and keeps server_connections truthful.
+ * (corrosion-host-agent/PROTOCOL.md) and keeps the fleet model truthful.
  *
- * Before this service existed, NOTHING persisted agent heartbeats:
- * companion_last_seen was written once at setup and connection_status stayed
- * 'connected' forever. Now: heartbeat -> last_seen + connected (row
- * auto-created on first contact), going_offline beacon -> offline, and a
- * staleness sweep marks hosts offline when heartbeats stop arriving.
+ * Writes the License → Host → Instance model (hosts + game_instances) from
+ * each heartbeat, AND maintains the legacy single-server `server_connections`
+ * row so the current panel keeps working during the fleet UI transition.
+ *
+ * Host identity: until enrollment issues a stable host id, a host is keyed by
+ * (license_id, hostname). One agent = one host today; the schema is already
+ * multi-host-ready.
  */
+interface HeartbeatPayload {
+  schema?: number;
+  timestamp?: string;
+  agent?: { version?: string; commit?: string; os?: string; arch?: string };
+  host?: {
+    hostname?: string | null;
+    cpu_percent?: number;
+    cpu_cores?: number;
+    mem_total_mb?: number;
+    mem_used_mb?: number;
+    uptime_seconds?: number;
+    disks?: AgentHostDisk[];
+  };
+  instances?: Array<{
+    id: string;
+    game: string;
+    label?: string | null;
+    state?: string;
+    uptime_seconds?: number;
+  }>;
+}
+
 @Injectable()
 export class HostAgentConsumerService implements OnApplicationBootstrap {
   private readonly logger = new Logger(HostAgentConsumerService.name);
 
-  /** licenseId -> cache expiry epoch-ms. Positive = exists, absent = unknown. */
   private knownLicenses = new Map<string, number>();
-  /** Unknown/garbage license ids we already warned about (anti log-spam). */
   private warnedUnknown = new Set<string>();
 
   private static readonly UUID_RE =
     /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;
   private static readonly LICENSE_CACHE_TTL_MS = 5 * 60_000;
-  /** 3x the agent's default 60s heartbeat (which jitters to max 72s). */
   private static readonly OFFLINE_AFTER_MS = 180_000;
 
   constructor(
@@ -37,6 +60,10 @@ export class HostAgentConsumerService implements OnApplicationBootstrap {
     private readonly connectionRepository: Repository<ServerConnection>,
     @InjectRepository(License)
     private readonly licenseRepository: Repository<License>,
+    @InjectRepository(AgentHost)
+    private readonly hostRepository: Repository<AgentHost>,
+    @InjectRepository(GameInstance)
+    private readonly instanceRepository: Repository<GameInstance>,
   ) {}
 
   // Bootstrap, not module-init: subscriptions registered before NatsService
@@ -44,10 +71,9 @@ export class HostAgentConsumerService implements OnApplicationBootstrap {
   onApplicationBootstrap() {
     this.nats.subscribe('corrosion.*.host.heartbeat', (data, subject) => {
       const licenseId = subject.split('.')[1];
-      void this.onHeartbeat(licenseId).catch((err) =>
+      void this.onHeartbeat(licenseId, data as HeartbeatPayload).catch((err) =>
         this.logger.error(`heartbeat handling failed for ${licenseId}: ${err.message}`, err.stack),
       );
-      void data; // payload telemetry is bridged to the browser; persistence here is liveness only
     });
 
     this.nats.subscribe('corrosion.*.host.going_offline', (_data, subject) => {
@@ -60,25 +86,24 @@ export class HostAgentConsumerService implements OnApplicationBootstrap {
     this.logger.log('Host agent (protocol v2) consumer subscriptions initialized');
   }
 
-  private async onHeartbeat(licenseId: string): Promise<void> {
+  private async onHeartbeat(licenseId: string, payload: HeartbeatPayload): Promise<void> {
     if (!(await this.isValidTenant(licenseId))) return;
-
     const now = new Date();
-    const existing = await this.connectionRepository.findOne({
-      where: { license_id: licenseId },
-    });
 
+    await this.updateLegacyConnection(licenseId, now);
+    const host = await this.upsertHost(licenseId, payload, now);
+    await this.upsertInstances(licenseId, host, payload, now);
+  }
+
+  /** Legacy single-server row — keeps the current panel working. */
+  private async updateLegacyConnection(licenseId: string, now: Date): Promise<void> {
+    const existing = await this.connectionRepository.findOne({ where: { license_id: licenseId } });
     if (existing) {
       await this.connectionRepository.update(
         { id: existing.id },
         { companion_last_seen: now, connection_status: 'connected', updated_at: now },
       );
-      if (existing.connection_status !== 'connected') {
-        this.logger.log(`host agent for license ${licenseId} is back online`);
-      }
     } else {
-      // First contact from a host agent: auto-register the connection so the
-      // panel lights up without a manual setup step.
       await this.connectionRepository.save(
         this.connectionRepository.create({
           license_id: licenseId,
@@ -87,28 +112,102 @@ export class HostAgentConsumerService implements OnApplicationBootstrap {
           companion_last_seen: now,
         }),
       );
-      this.logger.log(`host agent registered for license ${licenseId} (first heartbeat)`);
+    }
+  }
+
+  /** Upsert the fleet host row, keyed by (license_id, hostname). */
+  private async upsertHost(licenseId: string, payload: HeartbeatPayload, now: Date): Promise<AgentHost> {
+    const hostname = payload.host?.hostname ?? '';
+    const fields = {
+      agent_version: payload.agent?.version ?? null,
+      agent_commit: payload.agent?.commit ?? null,
+      os: payload.agent?.os ?? null,
+      arch: payload.agent?.arch ?? null,
+      status: 'connected',
+      last_heartbeat_at: now,
+      cpu_percent: payload.host?.cpu_percent ?? null,
+      cpu_cores: payload.host?.cpu_cores ?? null,
+      mem_total_mb: payload.host?.mem_total_mb ?? null,
+      mem_used_mb: payload.host?.mem_used_mb ?? null,
+      uptime_seconds: payload.host?.uptime_seconds ?? null,
+      disks: payload.host?.disks ?? null,
+      updated_at: now,
+    };
+
+    const existing = await this.hostRepository.findOne({
+      where: { license_id: licenseId, hostname },
+    });
+    if (existing) {
+      await this.hostRepository.update({ id: existing.id }, fields);
+      return { ...existing, ...fields } as AgentHost;
+    }
+    const created = await this.hostRepository.save(
+      this.hostRepository.create({ license_id: licenseId, hostname, ...fields }),
+    );
+    this.logger.log(`host registered for license ${licenseId} (hostname '${hostname || 'unknown'}')`);
+    return created;
+  }
+
+  /** Upsert one game_instances row per heartbeat instance entry. */
+  private async upsertInstances(
+    licenseId: string,
+    host: AgentHost,
+    payload: HeartbeatPayload,
+    now: Date,
+  ): Promise<void> {
+    for (const inst of payload.instances ?? []) {
+      if (!inst?.id || !inst?.game) continue;
+      const fields = {
+        host_id: host.id,
+        game: inst.game,
+        label: inst.label ?? null,
+        state: inst.state ?? 'unknown',
+        uptime_seconds: inst.uptime_seconds ?? 0,
+        last_seen_at: now,
+        updated_at: now,
+      };
+      const existing = await this.instanceRepository.findOne({
+        where: { license_id: licenseId, agent_instance_id: inst.id },
+      });
+      if (existing) {
+        await this.instanceRepository.update({ id: existing.id }, fields);
+      } else {
+        await this.instanceRepository.save(
+          this.instanceRepository.create({
+            license_id: licenseId,
+            agent_instance_id: inst.id,
+            ...fields,
+          }),
+        );
+        this.logger.log(`instance '${inst.id}' (${inst.game}) registered for license ${licenseId}`);
+      }
     }
   }
 
   private async onGoingOffline(licenseId: string): Promise<void> {
     if (!(await this.isValidTenant(licenseId))) return;
-
+    const now = new Date();
     await this.connectionRepository.update(
       { license_id: licenseId },
-      { connection_status: 'offline', updated_at: new Date() },
+      { connection_status: 'offline', updated_at: now },
     );
-    this.logger.log(`host agent for license ${licenseId} went offline (graceful beacon)`);
+    await this.hostRepository.update(
+      { license_id: licenseId },
+      { status: 'offline', updated_at: now },
+    );
+    this.logger.log(`host(s) for license ${licenseId} went offline (graceful beacon)`);
   }
 
   /**
    * Heartbeats stopping must flip the panel to offline — an agent that
-   * crashes or loses network never sends the goodbye beacon.
+   * crashes or loses network never sends the goodbye beacon. Sweeps both the
+   * legacy connection and fleet hosts.
    */
   @Interval(60_000)
   async sweepStaleConnections(): Promise<void> {
     const threshold = new Date(Date.now() - HostAgentConsumerService.OFFLINE_AFTER_MS);
-    const result = await this.connectionRepository
+
+    const conn = await this.connectionRepository
       .createQueryBuilder()
       .update(ServerConnection)
       .set({ connection_status: 'offline', updated_at: () => 'NOW()' })
@@ -117,8 +216,18 @@ export class HostAgentConsumerService implements OnApplicationBootstrap {
       .andWhere('companion_last_seen < :threshold', { threshold })
       .execute();
 
-    if (result.affected) {
-      this.logger.warn(`marked ${result.affected} stale host connection(s) offline`);
+    const hosts = await this.hostRepository
+      .createQueryBuilder()
+      .update(AgentHost)
+      .set({ status: 'offline', updated_at: () => 'NOW()' })
+      .where('status = :connected', { connected: 'connected' })
+      .andWhere('last_heartbeat_at IS NOT NULL')
+      .andWhere('last_heartbeat_at < :threshold', { threshold })
+      .execute();
+
+    const affected = (conn.affected ?? 0) + (hosts.affected ?? 0);
+    if (affected) {
+      this.logger.warn(`marked ${affected} stale connection/host record(s) offline`);
     }
   }
 
@@ -132,7 +241,6 @@ export class HostAgentConsumerService implements OnApplicationBootstrap {
       this.warnUnknownOnce(licenseId, 'not a UUID');
       return false;
     }
-
     const cachedUntil = this.knownLicenses.get(licenseId);
     if (cachedUntil && cachedUntil > Date.now()) return true;
 
@@ -141,7 +249,6 @@ export class HostAgentConsumerService implements OnApplicationBootstrap {
       this.warnUnknownOnce(licenseId, 'no such license');
       return false;
     }
-
     this.knownLicenses.set(licenseId, Date.now() + HostAgentConsumerService.LICENSE_CACHE_TTL_MS);
     return true;
   }

backend/migrations/022_fleet_model.sql

@@ -0,0 +1,102 @@
+-- Fleet data model — License → Host → Instance (with optional Cluster)
+--
+-- ADDITIVE: existing server_connections / server_config / server_stats are
+-- left untouched so the current single-server panel keeps working. The
+-- host-agent consumer writes BOTH the legacy connection row and these fleet
+-- tables during the transition; the panel migrates to the fleet tables in a
+-- later phase.
+--
+-- Shape mirrors the host agent's wire protocol v2 heartbeat:
+--   host{} block          → agent_hosts
+--   instances[] entries   → game_instances
+-- Host metrics (CPU/RAM/disk) live on the HOST, not duplicated per instance.
+--
+-- Named `agent_hosts` (not `hosts`) to avoid collision with the existing B2B
+-- `hosts` table (hosting-partner companies) — different concept entirely.
+
+-----------------------------------------------------------
+-- AGENT_HOSTS — one Corrosion host agent / one machine
+-----------------------------------------------------------
+CREATE TABLE IF NOT EXISTS agent_hosts (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    license_id UUID NOT NULL REFERENCES licenses(id) ON DELETE CASCADE,
+    -- Natural key until enrollment issues a stable host identity.
+    hostname VARCHAR(255) NOT NULL DEFAULT '',
+    agent_version VARCHAR(64),
+    agent_commit VARCHAR(64),
+    os VARCHAR(32),
+    arch VARCHAR(32),
+    status VARCHAR(20) NOT NULL DEFAULT 'offline'
+        CHECK (status IN ('connected', 'degraded', 'offline')),
+    last_heartbeat_at TIMESTAMPTZ,
+    cpu_percent DOUBLE PRECISION,
+    cpu_cores INTEGER,
+    mem_total_mb BIGINT,
+    mem_used_mb BIGINT,
+    uptime_seconds BIGINT,
+    disks JSONB,  -- [{ "mount": "/", "total_mb": n, "free_mb": n }]
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (license_id, hostname)
+);
+CREATE INDEX IF NOT EXISTS idx_agent_hosts_license ON agent_hosts(license_id);
+
+-----------------------------------------------------------
+-- INSTANCE CLUSTERS — optional grouping (Soulmask main/child, Dune battlegroup)
+-- Reserved now; cluster logic ships with those game adapters.
+-----------------------------------------------------------
+CREATE TABLE IF NOT EXISTS instance_clusters (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    license_id UUID NOT NULL REFERENCES licenses(id) ON DELETE CASCADE,
+    game VARCHAR(32) NOT NULL,
+    name VARCHAR(255) NOT NULL,
+    topology VARCHAR(32),  -- main_client | battlegroup
+    config JSONB,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+CREATE INDEX IF NOT EXISTS idx_clusters_license ON instance_clusters(license_id);
+
+-----------------------------------------------------------
+-- GAME INSTANCES — one game server process / orchestrated unit.
+-- The billing unit (plans count instances).
+-----------------------------------------------------------
+CREATE TABLE IF NOT EXISTS game_instances (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    license_id UUID NOT NULL REFERENCES licenses(id) ON DELETE CASCADE,
+    host_id UUID REFERENCES agent_hosts(id) ON DELETE SET NULL,
+    cluster_id UUID REFERENCES instance_clusters(id) ON DELETE SET NULL,
+    -- The agent's instance slug; the NATS subject segment.
+    agent_instance_id VARCHAR(64) NOT NULL,
+    game VARCHAR(32) NOT NULL,
+    label VARCHAR(255),
+    -- running | stopped | starting | stopping | crashed
+    -- | configured | missing_root | unmanaged | unknown
+    state VARCHAR(32) NOT NULL DEFAULT 'unknown',
+    root_path TEXT,
+    uptime_seconds BIGINT NOT NULL DEFAULT 0,
+    last_seen_at TIMESTAMPTZ,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (license_id, agent_instance_id)
+);
+CREATE INDEX IF NOT EXISTS idx_instances_license ON game_instances(license_id);
+CREATE INDEX IF NOT EXISTS idx_instances_host ON game_instances(host_id);
+
+-----------------------------------------------------------
+-- INSTANCE STATS — per-instance time series (game metrics).
+-- Populated once game-level telemetry (player count/FPS via RCON/plugin) is
+-- collected; the host heartbeat carries host metrics, not game metrics.
+-----------------------------------------------------------
+CREATE TABLE IF NOT EXISTS instance_stats (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    instance_id UUID NOT NULL REFERENCES game_instances(id) ON DELETE CASCADE,
+    license_id UUID NOT NULL REFERENCES licenses(id) ON DELETE CASCADE,
+    player_count INTEGER NOT NULL DEFAULT 0,
+    max_players INTEGER NOT NULL DEFAULT 0,
+    fps DOUBLE PRECISION NOT NULL DEFAULT 0,
+    memory_usage_mb INTEGER NOT NULL DEFAULT 0,
+    recorded_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+CREATE INDEX IF NOT EXISTS idx_instance_stats_instance
+    ON instance_stats(instance_id, recorded_at DESC);