refactor(guild): drop system-key bypass + announce-only-system limit

Pairs with Dialectic.Backend@5cf4302 which removes the backend-driven
broadcaster that was the only consumer of the x-fabric-system-key
header path. Backend cleanup is complete on the consumer side; this
removes the producer-side surface.

Removed:
  - ApiKeyGuard: x-fabric-system-key bypass branch (sysExpected /
    sysProvided / req.isSystem flag) — only Bearer flow remains.
  - messaging.controller.create(): the entire 'if (req.isSystem)'
    branch including the SYSTEM_USER_ID='00000000-...-0000' sentinel
    persistence path.
  - messaging.controller.create(): the 'if (xType === announce) throw
    announce_system_only' gate. Announce channels are now ordinary
    channels — any participant can POST. Use case: agents post one-off
    recruitment broadcasts via fabric-send-message (e.g. dialectic
    'come participate in topic X' messages).
  - cli/gen-system-api-key.ts: deleted (was the generator for the env
    that's no longer read).

Kept:
  - channel.purpose field + PATCH /api/channels/:id (member auth for
    setting purpose — agents use this to label channels for
    fabric-channel-list discoverability).
  - cli/print-commands-sync-key.ts (separate key, separate lifecycle).
  - GuildRole.isSystem flag (unrelated — system-role permission gate).

src/agents/agent-presence.controller.ts

@@ -0,0 +1,42 @@
+import { BadRequestException, Body, Controller, Get, Param, Put } from '@nestjs/common';
+import { AgentPresenceService, PresenceStatus } from './agent-presence.service.js';
+
+const VALID: PresenceStatus[] = ['idle', 'on_call', 'busy', 'exhausted', 'offline', 'unknown'];
+
+interface PutBody {
+  status?: string;
+  source?: string;
+}
+
+@Controller('agents/:userId/presence')
+export class AgentPresenceController {
+  constructor(private readonly svc: AgentPresenceService) {}
+
+  /**
+   * Read a user's current presence cache row.
+   * Auth: ApiKeyGuard (global). Any introspected center user can read.
+   */
+  @Get()
+  async get(@Param('userId') userId: string): Promise<{ userId: string; status: PresenceStatus }> {
+    const status = await this.svc.getStatus(userId);
+    return { userId, status };
+  }
+
+  /**
+   * Push a presence update. Called by Fabric.OpenclawPlugin's
+   * `presence-sync` loop on each delta. Auth: ApiKeyGuard (global) +
+   * the plugin uses its center-introspected api key.
+   *
+   * `source` is a debug tag describing who pushed (e.g. 'hf-plugin',
+   * 'manual'). Stored verbatim for trail.
+   */
+  @Put()
+  async put(@Param('userId') userId: string, @Body() body: PutBody): Promise<{ userId: string; status: PresenceStatus }> {
+    if (!body?.status || !VALID.includes(body.status as PresenceStatus)) {
+      throw new BadRequestException(`status must be one of ${VALID.join('|')}`);
+    }
+    const source = (body.source ?? 'unknown').slice(0, 64);
+    const row = await this.svc.setStatus(userId, body.status as PresenceStatus, source);
+    return { userId: row.userId, status: row.status };
+  }
+}

src/agents/agent-presence.module.ts

@@ -0,0 +1,13 @@
+import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { AgentPresence } from '../entities/agent-presence.entity.js';
+import { AgentPresenceController } from './agent-presence.controller.js';
+import { AgentPresenceService } from './agent-presence.service.js';
+
+@Module({
+  imports: [TypeOrmModule.forFeature([AgentPresence])],
+  controllers: [AgentPresenceController],
+  providers: [AgentPresenceService],
+  exports: [AgentPresenceService],
+})
+export class AgentPresenceModule {}

src/agents/agent-presence.service.ts

@@ -0,0 +1,53 @@
+import { Injectable } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { AgentPresence } from '../entities/agent-presence.entity.js';
+
+export type PresenceStatus = 'idle' | 'on_call' | 'busy' | 'exhausted' | 'offline' | 'unknown';
+
+@Injectable()
+export class AgentPresenceService {
+  constructor(
+    @InjectRepository(AgentPresence)
+    private readonly repo: Repository<AgentPresence>,
+  ) {}
+
+  /**
+   * Get a user's current presence. Returns 'unknown' if no row.
+   * Used by `RealtimeGateway` per-recipient when xType === 'announce'.
+   */
+  async getStatus(userId: string): Promise<PresenceStatus> {
+    if (!userId) return 'unknown';
+    const row = await this.repo.findOne({ where: { userId } });
+    return row?.status ?? 'unknown';
+  }
+
+  /** Bulk variant for delivery-time lookups across many recipients in one trip. */
+  async getStatusMap(userIds: string[]): Promise<Map<string, PresenceStatus>> {
+    const out = new Map<string, PresenceStatus>();
+    for (const id of userIds) out.set(id, 'unknown');
+    if (userIds.length === 0) return out;
+    const rows = await this.repo
+      .createQueryBuilder('p')
+      .where('p.userId IN (:...ids)', { ids: userIds })
+      .getMany();
+    for (const r of rows) out.set(r.userId, r.status);
+    return out;
+  }
+
+  /**
+   * Upsert a user's presence. Source is a free-text tag for debugging
+   * (e.g. "hf-plugin", "manual", "test"). PUT /agents/:id/presence
+   * calls this; the plugin pushes only on diff so writes are sparse.
+   */
+  async setStatus(userId: string, status: PresenceStatus, source: string): Promise<AgentPresence> {
+    const existing = await this.repo.findOne({ where: { userId } });
+    if (existing) {
+      existing.status = status;
+      existing.source = source;
+      return this.repo.save(existing);
+    }
+    const row = this.repo.create({ userId, status, source });
+    return this.repo.save(row);
+  }
+}

src/app.module.ts

@@ -16,6 +16,7 @@ import { MembersModule } from './members/members.module.js';
 import { FilesModule } from './files/files.module.js';
 import { CanvasModule } from './canvas/canvas.module.js';
 import { CommandsModule } from './commands/commands.module.js';
+import { AgentPresenceModule } from './agents/agent-presence.module.js';
 
 @Module({
   imports: [
@@ -30,6 +31,7 @@ import { CommandsModule } from './commands/commands.module.js';
     FilesModule,
     CanvasModule,
     CommandsModule,
+    AgentPresenceModule,
   ],
   controllers: [HealthController, MetricsController],
   providers: [

src/channels/channels.controller.ts

@@ -1,4 +1,4 @@
-import { Body, Controller, Get, Param, Post, Query, Req, UnauthorizedException } from '@nestjs/common';
+import { BadRequestException, Body, Controller, Get, Param, Patch, Post, Query, Req, UnauthorizedException } from '@nestjs/common';
 import { ChannelsService } from './channels.service.js';
 
 // ApiKeyGuard attaches the introspected Center user id onto the request.
@@ -32,11 +32,33 @@ export class ChannelsController {
         bypassUserIds: Array.isArray(body.bypassUserIds)
           ? (body.bypassUserIds as string[])
           : [],
+        purpose: body.purpose as string | undefined,
       },
       userId,
     );
   }
 
+  // Patch a channel's free-form purpose. Body: { purpose: string }. Pass
+  // empty string to clear. Auth: channel member (or anyone for public
+  // channels, mirroring close()). Frontend doesn't call this today —
+  // intended for agent-side use (fabric-channel-set-purpose tool).
+  @Patch(':id')
+  patch(
+    @Req() req: AuthedRequest,
+    @Param('id') channelId: string,
+    @Body() body: Record<string, unknown>,
+  ) {
+    const userId = req.userId ?? '';
+    if (!userId) throw new UnauthorizedException('missing user');
+    // Only `purpose` is patchable today. Future patchable fields would
+    // get their own typed branch; we explicitly NOT allow {} no-op patches
+    // because that signals a caller bug.
+    if (typeof body.purpose !== 'string') {
+      throw new BadRequestException('purpose (string) is required');
+    }
+    return this.channelsService.updatePurpose(channelId, userId, body.purpose);
+  }
+
   // Move an order member into the bypass list (discuss/work only).
   @Post(':id/bypass')
   bypass(

src/channels/channels.service.ts

@@ -7,7 +7,7 @@ import { WakeMapping } from '../entities/wake-mapping.entity.js';
 import { TurnService } from './turn.service.js';
 import { RealtimeGateway } from '../realtime/realtime.gateway.js';
 
-const X_TYPES = ['general', 'work', 'report', 'discuss', 'triage', 'custom', 'dm'] as const;
+const X_TYPES = ['general', 'work', 'report', 'discuss', 'triage', 'custom', 'dm', 'announce'] as const;
 type XType = (typeof X_TYPES)[number];
 
 type CreateChannelInput = {
@@ -24,6 +24,10 @@ type CreateChannelInput = {
   // discuss/work only: members excluded from rotation (no wakeup unless
   // @-mentioned). order and bypass partition the members disjointly.
   bypassUserIds?: string[];
+  // Free-form description of what this channel is for. Optional; agents
+  // typically fill it when creating, members can later edit via
+  // PATCH /api/channels/:id.
+  purpose?: string;
 };
 
 @Injectable()
@@ -166,6 +170,9 @@ export class ChannelsService {
     // allowed (create() always makes a fresh one, no dedup).
     const isPublic = xType === 'dm' ? false : Boolean(input.isPublic);
 
+    const purposeRaw = String(input.purpose ?? '').trim();
+    const purpose = purposeRaw === '' ? null : purposeRaw;
+
     const channel = await this.channelRepo.save(
       this.channelRepo.create({
         guildId,
@@ -174,6 +181,7 @@ export class ChannelsService {
         kind: input.kind === 'announcement' ? 'announcement' : 'text',
         isPrivate: !isPublic,
         isPublic,
+        purpose,
         lastSeq: 0,
       }),
     );
@@ -219,6 +227,27 @@ export class ChannelsService {
     return channel;
   }
 
+  // Update a channel's free-form purpose. Any channel member may do this
+  // (or any guild user if the channel is public, mirroring closeChannel's
+  // member-or-public rule). Pass an empty string to clear.
+  async updatePurpose(channelId: string, actorUserId: string, purpose: string) {
+    const channel = await this.channelRepo.findOne({ where: { id: channelId } });
+    if (!channel) throw new NotFoundException('channel not found');
+    const member = await this.memberRepo.findOne({ where: { channelId, userId: actorUserId } });
+    if (!member && !channel.isPublic) {
+      throw new ForbiddenException('not a channel member');
+    }
+    const trimmed = String(purpose ?? '').trim();
+    channel.purpose = trimmed === '' ? null : trimmed;
+    const saved = await this.channelRepo.save(channel);
+    return {
+      id: saved.id,
+      name: saved.name,
+      xType: saved.xType,
+      purpose: saved.purpose,
+    };
+  }
+
   // Move an order member into the bypass list (discuss/work only).
   // Any channel member may do this.
   async moveToBypass(channelId: string, actorUserId: string, targetUserId: string) {

src/database.config.ts

@@ -14,6 +14,7 @@ import { IdempotencyRecord } from './entities/idempotency-record.entity.js';
 import { StoredFile } from './entities/stored-file.entity.js';
 import { ChannelCanvas } from './entities/channel-canvas.entity.js';
 import { GuildCommand } from './entities/guild-command.entity.js';
+import { AgentPresence } from './entities/agent-presence.entity.js';
 
 export const buildTypeOrmConfig = (): TypeOrmModuleOptions => ({
   type: 'mysql',
@@ -38,6 +39,7 @@ export const buildTypeOrmConfig = (): TypeOrmModuleOptions => ({
     StoredFile,
     ChannelCanvas,
     GuildCommand,
+    AgentPresence,
   ],
   synchronize: (process.env.FABRIC_BACKEND_GUILD_DB_SYNC ?? 'true') === 'true',
   logging: (process.env.FABRIC_BACKEND_GUILD_DB_LOGGING ?? 'false') === 'true',

src/entities/agent-presence.entity.ts

@@ -0,0 +1,35 @@
+import { Column, Entity, PrimaryColumn, UpdateDateColumn } from 'typeorm';
+
+/**
+ * Per-user (typically agent) presence cache.
+ *
+ * Populated by Fabric.OpenclawPlugin's presence-sync loop: every ~30s
+ * it reads each connected agent's HF status from the cross-plugin
+ * `globalThis.__hfAgentStatus.get(agentId)` (exposed by
+ * HarborForge.OpenclawPlugin) and pushes diffs via
+ * `PUT /agents/:userId/presence`.
+ *
+ * Used by `RealtimeGateway.computeDelivery` for `announce`-type
+ * channels to skip delivery to recipients whose status is `busy`.
+ * Defaults to `unknown` if no row exists (treated as not-busy).
+ */
+@Entity('agent_presences')
+export class AgentPresence {
+  // Same id as the Fabric Center user id (UUID v4 string, char(36)).
+  @PrimaryColumn({ type: 'char', length: 36 })
+  userId!: string;
+
+  @Column({
+    type: 'enum',
+    enum: ['idle', 'on_call', 'busy', 'exhausted', 'offline', 'unknown'],
+    default: 'unknown',
+  })
+  status!: 'idle' | 'on_call' | 'busy' | 'exhausted' | 'offline' | 'unknown';
+
+  /** Free-text source tag for debugging ("hf-plugin", "manual", etc.). */
+  @Column({ type: 'varchar', length: 64, default: 'unknown' })
+  source!: string;
+
+  @UpdateDateColumn()
+  updatedAt!: Date;
+}

src/entities/channel.entity.ts

@@ -16,13 +16,23 @@ export class Channel {
   @Column({
     name: 'x_type',
     type: 'enum',
-    enum: ['general', 'work', 'report', 'discuss', 'triage', 'custom', 'dm'],
+    enum: ['general', 'work', 'report', 'discuss', 'triage', 'custom', 'dm', 'announce'],
   })
-  xType!: 'general' | 'work' | 'report' | 'discuss' | 'triage' | 'custom' | 'dm';
+  xType!: 'general' | 'work' | 'report' | 'discuss' | 'triage' | 'custom' | 'dm' | 'announce';
 
   @Column({ type: 'varchar', length: 16, default: 'text' })
   kind!: 'text' | 'announcement';
 
+  // Free-form description of what this channel is for — what topics get
+  // posted, who participates, why it exists. Surfaced via GET /api/channels
+  // so agents can pick a channel by intent ("which announce channel is for
+  // debate broadcasts?") without channel id hard-coded into workflows.
+  // Any channel member can set it via PATCH /api/channels/:id (writes
+  // require membership the same way moveToBypass / close do). The frontend
+  // create form does NOT post this today — purpose stays optional.
+  @Column({ type: 'text', nullable: true })
+  purpose!: string | null;
+
   @Column({ type: 'boolean', default: false })
   isPrivate!: boolean;
 

src/messaging/messaging.controller.ts

@@ -166,6 +166,11 @@ export class MessagingController {
     // Guild C-1: caller must be a participant of the channel, and the
     // author is always the authenticated user — body.authorUserId is
     // ignored so a caller can never post as someone else.
+    //
+    // announce channels: any participant can POST. Use case is one-off
+    // recruitment / broadcast messages posted by the agent that just
+    // created the originating topic (e.g. dialectic invites). No
+    // server-side privileged path — author is always a real user.
     const userId = String(req.userId ?? '');
     if (!userId) throw new ForbiddenException('missing user');
     const channel = await this.assertParticipant(channelId, userId);

src/realtime/realtime.gateway.ts

@@ -11,7 +11,17 @@ import { Logger } from '@nestjs/common';
 import { Server, Socket } from 'socket.io';
 import { introspectGuildToken } from '../common/center-auth.js';
 
-type XType = 'general' | 'work' | 'report' | 'discuss' | 'triage' | 'custom' | 'dm';
+type XType = 'general' | 'work' | 'report' | 'discuss' | 'triage' | 'custom' | 'dm' | 'announce';
+
+/**
+ * Cross-presence info needed by `announce`-type delivery: a recipient
+ * with hf-side status === 'busy' has the message discarded silently
+ * (don't enter their session, no UI emit). Other statuses + non-announce
+ * channels are unaffected. Presence is sourced from the
+ * `agent_presences` table populated by Fabric.OpenclawPlugin's
+ * presence-sync loop (which reads from HF plugin's `__hfAgentStatus`).
+ */
+export type PresenceStatus = 'idle' | 'on_call' | 'busy' | 'exhausted' | 'offline' | 'unknown';
 
 /**
  * Per-recipient delivery decision for a non-rotating channel message.
@@ -43,10 +53,12 @@ export interface ComputeDeliveryArgs {
   mentionUserIds?: Set<string>;
   /** Single Center-scoped admin userId, or null. */
   adminUserId?: string | null;
+  /** Recipient's current presence; only consulted for `announce` xType. Defaults to 'unknown' (treated as not-busy). */
+  recipientPresence?: PresenceStatus;
 }
 
 export function computeDelivery(args: ComputeDeliveryArgs): DeliveryDecision {
-  const { xType, recipientUserId, authorUserId, wakeUserIds, mentionUserIds, adminUserId } = args;
+  const { xType, recipientUserId, authorUserId, wakeUserIds, mentionUserIds, adminUserId, recipientPresence } = args;
   if (recipientUserId === authorUserId) return 'skip';
 
   switch (xType) {
@@ -67,6 +79,16 @@ export function computeDelivery(args: ComputeDeliveryArgs): DeliveryDecision {
       return wakeUserIds.has(recipientUserId) ? 'wake' : 'observer';
     case 'dm':
       return 'wake';
+    case 'announce':
+      // System-broadcast channels (e.g. Dialectic topic announcements).
+      // Recipients with HF status === 'busy' have the message discarded
+      // silently — busy agents should not be distracted by signup pings
+      // they can't act on. All other presences (idle/on_call/exhausted/
+      // offline/unknown) get the message as 'observer' (no wake): the
+      // channel itself is browsable; agents proactively decide what to
+      // do with announcements when they next look at their inbox.
+      if (recipientPresence === 'busy') return 'skip';
+      return 'observer';
     default:
       // report (and anything else): deliver as observer, no wake
       return 'observer';
@@ -100,6 +122,12 @@ export class RealtimeGateway implements OnGatewayConnection, OnGatewayDisconnect
   private readonly logger = new Logger(RealtimeGateway.name);
   private readonly onlineUsers = new Set<string>();
 
+  // Optional: injected at module wiring time. Used by emitMessageCreated
+  // to pre-load recipient presence for announce-type channels.
+  // Typed loosely to avoid a circular import between realtime and agents
+  // modules; the actual interface lives in agents/agent-presence.service.
+  presence?: { getStatusMap(ids: string[]): Promise<Map<string, PresenceStatus>> };
+
   private userIdFromClient(client: Socket): string {
     const authUser = client.handshake.auth?.userId;
     const headerUser = client.handshake.headers['x-user-id'];
@@ -225,7 +253,8 @@ export class RealtimeGateway implements OnGatewayConnection, OnGatewayDisconnect
   // Emits message.created per-recipient using the 3-state delivery
   // decision (wake / observer / skip). Skipped recipients receive
   // nothing — used by triage channels to keep non-on-duty / non-mention
-  // / non-admin users completely out of the loop.
+  // / non-admin users completely out of the loop, and by announce
+  // channels to suppress delivery to recipients whose presence is busy.
   async emitMessageCreated(
     channelId: string,
     data: Record<string, unknown>,
@@ -239,6 +268,18 @@ export class RealtimeGateway implements OnGatewayConnection, OnGatewayDisconnect
     },
   ): Promise<void> {
     const sockets = await this.server.in(`channel:${channelId}`).fetchSockets();
+
+    // For announce-type channels, pre-load presence for all recipients
+    // in one query so the per-recipient loop doesn't fan out to N round
+    // trips. For other xTypes, presence is irrelevant — skip the lookup.
+    let presenceMap: Map<string, PresenceStatus> | undefined;
+    if (ctx.xType === 'announce' && this.presence) {
+      const recipientIds = sockets
+        .map((s) => (typeof s.data.userId === 'string' ? (s.data.userId as string) : ''))
+        .filter((id) => id && !id.startsWith('anon:'));
+      presenceMap = await this.presence.getStatusMap(recipientIds);
+    }
+
     for (const s of sockets) {
       const recipientUserId = typeof s.data.userId === 'string' ? s.data.userId : `anon:${s.id}`;
       const decision = computeDelivery({
@@ -248,6 +289,7 @@ export class RealtimeGateway implements OnGatewayConnection, OnGatewayDisconnect
         wakeUserIds: ctx.wakeUserIds,
         mentionUserIds: ctx.mentionUserIds,
         adminUserId: ctx.adminUserId,
+        recipientPresence: presenceMap?.get(recipientUserId) ?? 'unknown',
       });
       if (decision === 'skip') continue;
       s.emit('message.created', {

src/realtime/realtime.module.ts

@@ -1,9 +1,25 @@
-import { Global, Module } from '@nestjs/common';
+import { Global, Module, OnModuleInit } from '@nestjs/common';
 import { RealtimeGateway } from './realtime.gateway.js';
+import { AgentPresenceModule } from '../agents/agent-presence.module.js';
+import { AgentPresenceService } from '../agents/agent-presence.service.js';
 
 @Global()
 @Module({
+  imports: [AgentPresenceModule],
   providers: [RealtimeGateway],
   exports: [RealtimeGateway],
 })
-export class RealtimeModule {}
+export class RealtimeModule implements OnModuleInit {
+  // Wire presence into the gateway at startup. Using assignment (vs
+  // constructor injection) keeps the gateway free of the agents-module
+  // import — no risk of circular dependency, and announce-channel
+  // delivery degrades gracefully (presence stays undefined → 'unknown'
+  // status → no busy-discard) if AgentPresenceModule is ever removed.
+  constructor(
+    private readonly gateway: RealtimeGateway,
+    private readonly presence: AgentPresenceService,
+  ) {}
+  onModuleInit(): void {
+    this.gateway.presence = this.presence;
+  }
+}