feat(ai-chat): agent roles (admin-defined persona + optional model)

Reusable, workspace-shared agent roles for the built-in AI chat. A role is
a named persona (system-prompt instructions) + optional model override; a
chat is bound to a role at creation and applies it every turn.

Backend:
- migration 20260620T120000: ai_agent_roles table + ai_chats.role_id
  (FK ON DELETE SET NULL); hand-merged types into db.d.ts/entity.types.ts
  (db.d.ts is hand-curated here, full codegen would clobber it).
- core/ai-chat/roles: CRUD module. list = any workspace member; create/
  update/delete = admin (Manage Settings ability, like ai-settings/mcp).
  All repo queries scoped by workspace_id; soft-delete (deleted_at).
- buildSystemPrompt gains roleInstructions: role REPLACES the persona base
  (admin prompt / DEFAULT_PROMPT) but SAFETY_FRAMEWORK + context are always
  still appended.
- stream(): role resolved from ai_chats.role_id for existing chats (never
  the request body -> no per-turn role swap); body.roleId only on creation.
  Disabled (enabled=false) and soft-deleted roles fall back to universal.
- getChatModel(workspaceId, override): role model_config can swap model id /
  driver; a driver without configured creds throws 503 with a clear message
  naming the driver+role, resolved BEFORE response hijack.

Client:
- new-chat role picker (enabled roles only, default Universal assistant),
  roleId sent only on the first message; role badge (emoji+name) in the chat
  header and conversation list; admin Agent-roles management section in
  Settings -> AI (add/edit/delete, MCP-form pattern).

Tests: ai-chat.prompt.spec (role layering + safety always present, incl.
jailbreak); ai.service.spec (override on unconfigured driver -> 503).

Implements docs/ai-agent-roles-plan.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/server/src/database/repos/ai-agent-roles/ai-agent-roles.repo.ts

@@ -0,0 +1,141 @@
+import { Injectable } from '@nestjs/common';
+import { InjectKysely } from 'nestjs-kysely';
+import { sql } from 'kysely';
+import { KyselyDB, KyselyTransaction } from '../../types/kysely.types';
+import { dbOrTx } from '../../utils';
+import { AiAgentRole } from '@docmost/db/types/entity.types';
+
+/** The jsonb shape persisted in `model_config` (loosely typed for the column). */
+type ModelConfigValue = Record<string, unknown> | null;
+
+/**
+ * Repository for per-workspace agent roles (admin-owned presets). All lookups
+ * are workspace-scoped and soft-delete aware (`deleted_at IS NULL`). A role
+ * shapes only the system-prompt persona + optional model override; it never
+ * widens or narrows the toolset or CASL boundary.
+ */
+@Injectable()
+export class AiAgentRoleRepo {
+  constructor(@InjectKysely() private readonly db: KyselyDB) {}
+
+  /** Single live (not soft-deleted) role scoped to the workspace. */
+  async findById(
+    id: string,
+    workspaceId: string,
+  ): Promise<AiAgentRole | undefined> {
+    return this.db
+      .selectFrom('aiAgentRoles')
+      .selectAll('aiAgentRoles')
+      .where('id', '=', id)
+      .where('workspaceId', '=', workspaceId)
+      .where('deletedAt', 'is', null)
+      .executeTakeFirst();
+  }
+
+  /** All live roles for the workspace (management list + chat picker). */
+  async listByWorkspace(workspaceId: string): Promise<AiAgentRole[]> {
+    return this.db
+      .selectFrom('aiAgentRoles')
+      .selectAll('aiAgentRoles')
+      .where('workspaceId', '=', workspaceId)
+      .where('deletedAt', 'is', null)
+      .orderBy('createdAt', 'asc')
+      .execute();
+  }
+
+  async insert(
+    values: {
+      workspaceId: string;
+      creatorId?: string | null;
+      name: string;
+      emoji?: string | null;
+      description?: string | null;
+      instructions: string;
+      modelConfig?: ModelConfigValue;
+      enabled?: boolean;
+    },
+    trx?: KyselyTransaction,
+  ): Promise<AiAgentRole> {
+    const db = dbOrTx(this.db, trx);
+    return db
+      .insertInto('aiAgentRoles')
+      .values({
+        workspaceId: values.workspaceId,
+        creatorId: values.creatorId ?? null,
+        name: values.name,
+        emoji: values.emoji ?? null,
+        description: values.description ?? null,
+        instructions: values.instructions,
+        modelConfig: jsonbObject(values.modelConfig),
+        enabled: values.enabled ?? true,
+      })
+      .returningAll()
+      .executeTakeFirst();
+  }
+
+  async update(
+    id: string,
+    workspaceId: string,
+    patch: {
+      name?: string;
+      // undefined => unchanged; null => clear; string => set.
+      emoji?: string | null;
+      description?: string | null;
+      instructions?: string;
+      // undefined => unchanged; null => clear; object => set.
+      modelConfig?: ModelConfigValue;
+      enabled?: boolean;
+    },
+    trx?: KyselyTransaction,
+  ): Promise<void> {
+    const db = dbOrTx(this.db, trx);
+    const set: Record<string, unknown> = { updatedAt: new Date() };
+    if (patch.name !== undefined) set.name = patch.name;
+    if (patch.emoji !== undefined) set.emoji = patch.emoji;
+    if (patch.description !== undefined) set.description = patch.description;
+    if (patch.instructions !== undefined) set.instructions = patch.instructions;
+    if (patch.modelConfig !== undefined) {
+      set.modelConfig = jsonbObject(patch.modelConfig);
+    }
+    if (patch.enabled !== undefined) set.enabled = patch.enabled;
+    await db
+      .updateTable('aiAgentRoles')
+      .set(set)
+      .where('id', '=', id)
+      .where('workspaceId', '=', workspaceId)
+      .where('deletedAt', 'is', null)
+      .execute();
+  }
+
+  /** Soft delete (consistent with ai_chats). Bound chats keep their role_id; the
+   * stream resolves only live roles, so the chat degrades to universal. */
+  async softDelete(
+    id: string,
+    workspaceId: string,
+    trx?: KyselyTransaction,
+  ): Promise<void> {
+    const db = dbOrTx(this.db, trx);
+    await db
+      .updateTable('aiAgentRoles')
+      .set({ deletedAt: new Date() })
+      .where('id', '=', id)
+      .where('workspaceId', '=', workspaceId)
+      .where('deletedAt', 'is', null)
+      .execute();
+  }
+}
+
+/**
+ * Encode an object as a jsonb bind for the `model_config` column. The postgres
+ * driver would otherwise need an explicit cast; bind the JSON text and cast it.
+ * Returns null for null/undefined/empty objects. Cast to `any` because the
+ * generated column type is the broad `JsonValue` union, which a concrete object
+ * type is not structurally assignable to.
+ */
+function jsonbObject(value: ModelConfigValue | undefined) {
+  if (value === null || value === undefined || Object.keys(value).length === 0) {
+    return null;
+  }
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return sql`${JSON.stringify(value)}::jsonb` as any;
+}

apps/server/src/database/repos/ai-chat/ai-chat.repo.ts

@@ -29,20 +29,34 @@ export class AiChatRepo {
     workspaceId: string,
     pagination: PaginationOptions,
   ) {
+    // Left-join the bound role for the badge (emoji + name). Joined, not
+    // denormalized — the chat list is not a hot path. A soft-deleted role
+    // resolves to NULL so the badge disappears, matching the stream's behavior.
     const query = this.db
       .selectFrom('aiChats')
+      .leftJoin('aiAgentRoles', (join) =>
+        join
+          .onRef('aiAgentRoles.id', '=', 'aiChats.roleId')
+          .on('aiAgentRoles.deletedAt', 'is', null),
+      )
       .selectAll('aiChats')
-      .where('creatorId', '=', creatorId)
-      .where('workspaceId', '=', workspaceId)
-      .where('deletedAt', 'is', null);
+      .select([
+        'aiAgentRoles.name as roleName',
+        'aiAgentRoles.emoji as roleEmoji',
+      ])
+      .where('aiChats.creatorId', '=', creatorId)
+      .where('aiChats.workspaceId', '=', workspaceId)
+      .where('aiChats.deletedAt', 'is', null);
 
     return executeWithCursorPagination(query, {
       perPage: pagination.limit,
       cursor: pagination.cursor,
       beforeCursor: pagination.beforeCursor,
       fields: [
-        { expression: 'createdAt', direction: 'desc' },
-        { expression: 'id', direction: 'desc' },
+        // Qualify to aiChats — the join introduces an aiAgentRoles.createdAt/id
+        // that would otherwise make the ORDER BY / cursor comparison ambiguous.
+        { expression: 'aiChats.createdAt', direction: 'desc' },
+        { expression: 'aiChats.id', direction: 'desc' },
       ],
       parseCursor: (cursor) => ({
         createdAt: new Date(cursor.createdAt),