From 4fe42ead5627a4c98b028e365c2c6e11262cf5ff Mon Sep 17 00:00:00 2001
From: claude_code <claude_code@vvzvlad.xyz>
Date: Sat, 20 Jun 2026 19:54:36 +0300
Subject: [PATCH] feat(public-share): selectable agent-role identity + fix
 floating-icon overlap

Anonymous public-share AI assistant:
- Add a workspace setting `publicShareAssistantRoleId` so an admin can pick which
  agent role (identity/persona) the anonymous assistant adopts. The role's
  instructions REPLACE the built-in persona while the immutable safety framework
  is still always appended; the role's optional model override takes precedence
  over the cheap publicShareChatModel. Resolved server-authoritatively
  (workspace-scoped, soft-delete aware; disabled/missing roles fall back to the
  built-in persona, so the tool scope remains the real security boundary).
- Plumb the field through the update DTO, ai-settings service, the workspace.repo
  ALLOWED whitelist, resolve()/getMasked(), stream-time role resolution and the
  prompt/model, plus the settings UI: a new "Assistant identity" Select listing
  enabled roles (and surfacing a saved-but-disabled role explicitly).

Public-share branding / floating icon:
- Fix the AI assistant FAB overlapping the "Powered by ..." button (both were
  Affixed bottom-right): stack the FAB above the bottom-right branding.
- Rename "Powered by Docmost" -> "Powered by Gitmost" and point the link at the
  gitmost repo.

Tests: extend public-share-chat.spec (role persona replacement still appends the
safety framework, resolveShareRole edge cases, model-override precedence).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 .../public/locales/en-US/translation.json     |  4 +
 .../share/components/share-ai-widget.tsx      |  9 +-
 .../share/components/share-branding.tsx       |  7 +-
 .../components/ai-provider-settings.tsx       | 53 ++++++++++
 .../workspace/services/ai-settings-service.ts |  6 ++
 .../ai-chat/public-share-chat.controller.ts   |  9 +-
 .../core/ai-chat/public-share-chat.prompt.ts  | 32 ++++--
 .../core/ai-chat/public-share-chat.service.ts | 52 ++++++++--
 .../core/ai-chat/public-share-chat.spec.ts    | 99 ++++++++++++++++++-
 .../repos/workspace/workspace.repo.ts         |  2 +-
 .../integrations/ai/ai-settings.service.ts    |  6 ++
 apps/server/src/integrations/ai/ai.types.ts   |  9 ++
 .../ai/dto/update-ai-settings.dto.ts          |  6 ++
 13 files changed, 265 insertions(+), 29 deletions(-)

diff --git a/apps/client/public/locales/en-US/translation.json b/apps/client/public/locales/en-US/translation.json
index 314f400b..c04fc72d 100644
--- a/apps/client/public/locales/en-US/translation.json
+++ b/apps/client/public/locales/en-US/translation.json
@@ -529,6 +529,7 @@
   "Add 2FA method": "Add 2FA method",
   "Backup codes": "Backup codes",
   "Disable": "Disable",
+  "disabled": "disabled",
   "Invalid verification code": "Invalid verification code",
   "New backup codes have been generated": "New backup codes have been generated",
   "Failed to regenerate backup codes": "Failed to regenerate backup codes",
@@ -1135,6 +1136,9 @@
   "Public assistant model": "Public assistant model",
   "Defaults to the chat model": "Defaults to the chat model",
   "Optional cheaper model id for the public assistant. Empty uses the chat model above.": "Optional cheaper model id for the public assistant. Empty uses the chat model above.",
+  "Assistant identity": "Assistant identity",
+  "Pick an agent role whose persona the public assistant adopts. The safety rules always still apply.": "Pick an agent role whose persona the public assistant adopts. The safety rules always still apply.",
+  "Built-in assistant persona": "Built-in assistant persona",
   "Minimize": "Minimize",
   "Current context size": "Current context size",
   "AI agent": "AI agent",
diff --git a/apps/client/src/features/share/components/share-ai-widget.tsx b/apps/client/src/features/share/components/share-ai-widget.tsx
index 455d3cea..90d0b9af 100644
--- a/apps/client/src/features/share/components/share-ai-widget.tsx
+++ b/apps/client/src/features/share/components/share-ai-widget.tsx
@@ -93,7 +93,10 @@ export default function ShareAiWidget({ shareId, pageId }: ShareAiWidgetProps) {
 
   if (!open) {
     return (
-      <Affix position={{ bottom: 20, right: 20 }}>
+      // Offset 80px from the bottom so the FAB stacks ABOVE the bottom-right
+      // "Powered by Gitmost" branding button (share-branding.tsx) without
+      // overlapping it.
+      <Affix position={{ bottom: 80, right: 20 }}>
         <Tooltip label={t("Ask AI")} position="left">
           <ActionIcon
             size="xl"
@@ -110,7 +113,7 @@ export default function ShareAiWidget({ shareId, pageId }: ShareAiWidgetProps) {
   }
 
   return (
-    <Affix position={{ bottom: 20, right: 20 }}>
+    <Affix position={{ bottom: 80, right: 20 }}>
       <Paper
         shadow="md"
         radius="md"
@@ -119,7 +122,7 @@ export default function ShareAiWidget({ shareId, pageId }: ShareAiWidgetProps) {
           width: 360,
           maxWidth: "calc(100vw - 40px)",
           height: 480,
-          maxHeight: "calc(100vh - 40px)",
+          maxHeight: "calc(100vh - 100px)",
           display: "flex",
           flexDirection: "column",
         }}
diff --git a/apps/client/src/features/share/components/share-branding.tsx b/apps/client/src/features/share/components/share-branding.tsx
index 4b3dfb3e..0347700f 100644
--- a/apps/client/src/features/share/components/share-branding.tsx
+++ b/apps/client/src/features/share/components/share-branding.tsx
@@ -2,14 +2,17 @@ import { Affix, Button } from "@mantine/core";
 
 export default function ShareBranding() {
   return (
+    // Pinned to the bottom-RIGHT corner. The AI assistant FAB
+    // (share-ai-widget.tsx) is stacked ABOVE this with a higher `bottom`
+    // offset, so the two Affix elements never overlap.
     <Affix position={{ bottom: 20, right: 20 }}>
       <Button
         variant="default"
         component="a"
         target="_blank"
-        href="https://docmost.com?ref=public-share"
+        href="https://github.com/vvzvlad/gitmost?ref=public-share"
       >
-        Powered by Docmost
+        Powered by Gitmost
       </Button>
     </Affix>
   );
diff --git a/apps/client/src/features/workspace/components/settings/components/ai-provider-settings.tsx b/apps/client/src/features/workspace/components/settings/components/ai-provider-settings.tsx
index 82a19b22..e4ff8724 100644
--- a/apps/client/src/features/workspace/components/settings/components/ai-provider-settings.tsx
+++ b/apps/client/src/features/workspace/components/settings/components/ai-provider-settings.tsx
@@ -38,6 +38,8 @@ import {
   IAiSettingsUpdate,
   SttApiStyle,
 } from "@/features/workspace/services/ai-settings-service.ts";
+import { useAiRolesQuery } from "@/features/ai-chat/queries/ai-chat-query.ts";
+import { IAiRole } from "@/features/ai-chat/types/ai-chat.types.ts";
 import AiMcpServers from "./ai-mcp-servers.tsx";
 
 // No driver field: every endpoint is OpenAI-compatible, so the form carries only
@@ -47,6 +49,9 @@ const formSchema = z.object({
   chatModel: z.string(),
   // Cheap model id for the anonymous public-share assistant; empty = use chatModel.
   publicShareChatModel: z.string(),
+  // Agent-role id whose persona the public-share assistant adopts; empty =
+  // built-in locked persona.
+  publicShareAssistantRoleId: z.string(),
   embeddingModel: z.string(),
   baseUrl: z.string(),
   // Embedding-specific base URL. Empty means "use the chat base URL".
@@ -145,6 +150,10 @@ export default function AiProviderSettings() {
   const embedTest = useTestAiConnectionMutation();
   const sttTest = useTestAiConnectionMutation();
 
+  // Agent roles drive the public-share assistant identity picker. Admin-gated
+  // (the component returns early for non-admins), same as the AI settings query.
+  const { data: roles } = useAiRolesQuery(isAdmin);
+
   // Workspace-level feature toggles live in the card headers.
   const [workspace, setWorkspace] = useAtom(workspaceAtom);
   const [chatEnabled, setChatEnabled] = useState<boolean>(
@@ -187,6 +196,7 @@ export default function AiProviderSettings() {
     initialValues: {
       chatModel: "",
       publicShareChatModel: "",
+      publicShareAssistantRoleId: "",
       embeddingModel: "",
       baseUrl: "",
       embeddingBaseUrl: "",
@@ -207,6 +217,7 @@ export default function AiProviderSettings() {
     form.setValues({
       chatModel: settings.chatModel ?? "",
       publicShareChatModel: settings.publicShareChatModel ?? "",
+      publicShareAssistantRoleId: settings.publicShareAssistantRoleId ?? "",
       embeddingModel: settings.embeddingModel ?? "",
       baseUrl: settings.baseUrl ?? "",
       embeddingBaseUrl: settings.embeddingBaseUrl ?? "",
@@ -236,6 +247,9 @@ export default function AiProviderSettings() {
       // Cheap model id for the anonymous public-share assistant; empty falls
       // back to chatModel server-side.
       publicShareChatModel: values.publicShareChatModel,
+      // Agent-role id whose persona the public-share assistant adopts; empty =
+      // built-in locked persona server-side.
+      publicShareAssistantRoleId: values.publicShareAssistantRoleId,
       embeddingModel: values.embeddingModel,
       // The embedding base URL is optional; empty falls back to the chat base
       // URL server-side.
@@ -471,6 +485,34 @@ export default function AiProviderSettings() {
 
   const monoFont = "ui-monospace, Menlo, monospace";
 
+  // Public-share assistant identity options: a leading "built-in persona" entry
+  // (empty value, the server default) plus every enabled agent role. If the saved
+  // role was since disabled it is filtered out of the enabled list, so surface it
+  // explicitly (labeled "disabled") instead of letting the Select render a blank
+  // field for a still-stored id.
+  const selectedRoleId = form.values.publicShareAssistantRoleId;
+  const enabledRoles = (roles ?? []).filter((r: IAiRole) => r.enabled);
+  const selectedDisabledRole =
+    selectedRoleId.length > 0 &&
+    !enabledRoles.some((r: IAiRole) => r.id === selectedRoleId)
+      ? (roles ?? []).find((r: IAiRole) => r.id === selectedRoleId)
+      : undefined;
+  const roleOptions = [
+    { value: "", label: t("Built-in assistant persona") },
+    ...enabledRoles.map((r: IAiRole) => ({
+      value: r.id,
+      label: r.emoji ? `${r.emoji} ${r.name}` : r.name,
+    })),
+    ...(selectedDisabledRole
+      ? [
+          {
+            value: selectedDisabledRole.id,
+            label: `${selectedDisabledRole.emoji ? `${selectedDisabledRole.emoji} ` : ""}${selectedDisabledRole.name} (${t("disabled")})`,
+          },
+        ]
+      : []),
+  ];
+
   return (
     <Stack mt="sm">
       {/* Section header */}
@@ -590,6 +632,17 @@ export default function AiProviderSettings() {
             "Optional cheaper model id for the public assistant. Empty uses the chat model above.",
           )}
         </Text>
+        <Select
+          mt="sm"
+          label={t("Assistant identity")}
+          description={t(
+            "Pick an agent role whose persona the public assistant adopts. The safety rules always still apply.",
+          )}
+          data={roleOptions}
+          allowDeselect={false}
+          disabled={isLoading || !publicShareAssistantEnabled}
+          {...form.getInputProps("publicShareAssistantRoleId")}
+        />
 
         <Group mt="md" align="center">
           <Button
diff --git a/apps/client/src/features/workspace/services/ai-settings-service.ts b/apps/client/src/features/workspace/services/ai-settings-service.ts
index c18b37ff..36468b04 100644
--- a/apps/client/src/features/workspace/services/ai-settings-service.ts
+++ b/apps/client/src/features/workspace/services/ai-settings-service.ts
@@ -18,6 +18,9 @@ export interface IAiSettings {
   chatModel?: string;
   // Cheap model id for the anonymous public-share assistant; empty = chatModel.
   publicShareChatModel?: string;
+  // Agent-role id whose persona the public-share assistant adopts; empty =
+  // built-in locked persona.
+  publicShareAssistantRoleId?: string;
   embeddingModel?: string;
   baseUrl?: string;
   embeddingBaseUrl?: string;
@@ -45,6 +48,9 @@ export interface IAiSettingsUpdate {
   driver?: AiDriver;
   chatModel?: string;
   publicShareChatModel?: string;
+  // Agent-role id whose persona the public-share assistant adopts; empty =
+  // built-in locked persona.
+  publicShareAssistantRoleId?: string;
   embeddingModel?: string;
   baseUrl?: string;
   embeddingBaseUrl?: string;
diff --git a/apps/server/src/core/ai-chat/public-share-chat.controller.ts b/apps/server/src/core/ai-chat/public-share-chat.controller.ts
index cfa863ea..fa5a0a5f 100644
--- a/apps/server/src/core/ai-chat/public-share-chat.controller.ts
+++ b/apps/server/src/core/ai-chat/public-share-chat.controller.ts
@@ -12,7 +12,7 @@ import {
 } from '@nestjs/common';
 import { Throttle, ThrottlerGuard } from '@nestjs/throttler';
 import { FastifyReply, FastifyRequest } from 'fastify';
-import { Workspace } from '@docmost/db/types/entity.types';
+import { Workspace, AiAgentRole } from '@docmost/db/types/entity.types';
 import { Public } from '../../common/decorators/public.decorator';
 import { JwtAuthGuard } from '../../common/guards/jwt-auth.guard';
 import { AuthWorkspace } from '../../common/decorators/auth-workspace.decorator';
@@ -146,10 +146,14 @@ export class PublicShareChatController {
     //    yields a clean 503 (AiNotConfiguredException) BEFORE hijack. Only
     //    attempt this once the earlier gates passed, to avoid leaking timing.
     let model: Awaited<ReturnType<PublicShareChatService['getShareChatModel']>> | undefined;
+    // Admin-selected identity (agent role) for the anonymous assistant, resolved
+    // server-authoritatively. null = built-in locked persona.
+    let role: AiAgentRole | null = null;
     let providerConfigured = false;
     if (assistantEnabled && shareUsable && pageInShare) {
       try {
-        model = await this.publicShareChat.getShareChatModel(workspace.id);
+        role = await this.publicShareChat.resolveShareRole(workspace.id);
+        model = await this.publicShareChat.getShareChatModel(workspace.id, role);
         providerConfigured = true;
       } catch (err) {
         if (err instanceof AiNotConfiguredException) {
@@ -235,6 +239,7 @@ export class PublicShareChatController {
         res,
         signal: controller.signal,
         model: model!,
+        role,
       });
     } catch (err) {
       // After hijack we can no longer send a clean JSON error.
diff --git a/apps/server/src/core/ai-chat/public-share-chat.prompt.ts b/apps/server/src/core/ai-chat/public-share-chat.prompt.ts
index 2294da05..ba3b483d 100644
--- a/apps/server/src/core/ai-chat/public-share-chat.prompt.ts
+++ b/apps/server/src/core/ai-chat/public-share-chat.prompt.ts
@@ -4,9 +4,10 @@
  * This is a separate, locked-down persona from the authenticated agent
  * (`ai-chat.prompt.ts`). The caller is an unauthenticated visitor of a public
  * share, so the assistant is strictly read-only and scoped to the published
- * share tree. There is no admin-configurable text here — the persona and the
- * safety block are both immutable, because the security boundary is the tool
- * scope (the share tree), not any per-request input.
+ * share tree. An admin MAY select an agent role whose `instructions` REPLACE the
+ * built-in PERSONA, but the SAFETY_FRAMEWORK is immutable and is ALWAYS still
+ * appended — the security boundary remains the tool scope (the share tree), not
+ * any persona text or other per-request input.
  */
 
 /**
@@ -50,6 +51,12 @@ export interface BuildShareSystemPromptInput {
    * reads via the share-scoped tools, which reject pages outside the share.
    */
   openedPage?: { id?: string; title?: string } | null;
+  /**
+   * When an admin-selected agent role is active, its instructions REPLACE the
+   * built-in PERSONA; the SAFETY_FRAMEWORK is always still appended. Empty/null
+   * = keep the built-in locked persona.
+   */
+  roleInstructions?: string | null;
 }
 
 const PERSONA = [
@@ -64,13 +71,17 @@ const PERSONA = [
 ].join(' ');
 
 /**
- * Compose the locked system prompt for the public-share assistant: an immutable
- * persona, optional context (share title + opened page), then ALWAYS the
- * non-removable safety framework. There is no admin override path.
+ * Compose the system prompt for the public-share assistant: a persona, optional
+ * context (share title + opened page), then ALWAYS the non-removable safety
+ * framework. The persona defaults to the built-in locked PERSONA, but an
+ * admin-selected agent role's `roleInstructions` may REPLACE it; either way the
+ * SAFETY_FRAMEWORK is immutable and always appended, and the tool scope (the
+ * share tree) remains the real security boundary.
  */
 export function buildShareSystemPrompt({
   share,
   openedPage,
+  roleInstructions,
 }: BuildShareSystemPromptInput): string {
   let context = '';
 
@@ -91,5 +102,12 @@ export function buildShareSystemPrompt({
     context += `\nThe reader is currently viewing the page "${title}" (pageId: ${pageId.trim()}). When they refer to "this page" or "the current page", use that pageId with the read tool.`;
   }
 
-  return `${PERSONA}${context}\n${SAFETY_FRAMEWORK}`;
+  // An admin-selected role's instructions replace the built-in persona; the
+  // safety framework below is still always appended.
+  const persona =
+    typeof roleInstructions === 'string' && roleInstructions.trim().length > 0
+      ? roleInstructions.trim()
+      : PERSONA;
+
+  return `${persona}${context}\n${SAFETY_FRAMEWORK}`;
 }
diff --git a/apps/server/src/core/ai-chat/public-share-chat.service.ts b/apps/server/src/core/ai-chat/public-share-chat.service.ts
index 29b5380d..d385c4f0 100644
--- a/apps/server/src/core/ai-chat/public-share-chat.service.ts
+++ b/apps/server/src/core/ai-chat/public-share-chat.service.ts
@@ -8,10 +8,13 @@ import {
   type LanguageModel,
 } from 'ai';
 import { RedisService } from '@nestjs-labs/nestjs-ioredis';
+import { AiAgentRoleRepo } from '@docmost/db/repos/ai-agent-roles/ai-agent-roles.repo';
+import { AiAgentRole } from '@docmost/db/types/entity.types';
 import { AiService } from '../../integrations/ai/ai.service';
 import { AiSettingsService } from '../../integrations/ai/ai-settings.service';
 import { PublicShareChatToolsService } from './tools/public-share-chat-tools.service';
 import { buildShareSystemPrompt } from './public-share-chat.prompt';
+import { roleModelOverride } from './roles/role-model-config';
 import {
   PublicShareWorkspaceLimiter,
   createPublicShareWorkspaceLimiter,
@@ -47,6 +50,9 @@ export interface PublicShareChatStreamArgs {
   // Resolved by the controller BEFORE res.hijack() so an unconfigured provider
   // (AiNotConfiguredException -> 503) surfaces as clean JSON before streaming.
   model: LanguageModel;
+  // Pre-resolved by the controller; its instructions replace the locked persona,
+  // while the safety framework is still always appended. null = built-in persona.
+  role: AiAgentRole | null;
 }
 
 /**
@@ -103,6 +109,7 @@ export class PublicShareChatService {
     private readonly aiSettings: AiSettingsService,
     private readonly tools: PublicShareChatToolsService,
     redisService: RedisService,
+    private readonly aiAgentRoleRepo: AiAgentRoleRepo,
   ) {
     this.workspaceLimiter = createPublicShareWorkspaceLimiter(redisService);
   }
@@ -117,16 +124,41 @@ export class PublicShareChatService {
   }
 
   /**
-   * Resolve the public-share chat model BEFORE res.hijack() (clean 503 path).
-   * Uses the cheap `publicShareChatModel`, falling back to the workspace
-   * `chatModel` when unset.
-   *
-   * IMPORTANT: this override substitutes ONLY the model id. The driver, baseUrl
-   * and apiKey are reused from the workspace's main chat provider (see
-   * AiService.getChatModel) — the "cheap model" is NOT an isolated provider or
-   * key, just a different model on the SAME configured provider.
+   * Resolve the admin-selected agent role for the anonymous public-share
+   * assistant, scoped to the workspace and soft-delete aware. Returns null when
+   * no role is configured, or when the referenced role is missing or disabled —
+   * in which case the built-in locked persona applies. Mirrors the authenticated
+   * chat's server-authoritative role resolution.
    */
-  async getShareChatModel(workspaceId: string): Promise<LanguageModel> {
+  async resolveShareRole(workspaceId: string): Promise<AiAgentRole | null> {
+    const resolved = await this.aiSettings.resolve(workspaceId);
+    const roleId = resolved?.publicShareAssistantRoleId;
+    if (!roleId) return null;
+    const role = await this.aiAgentRoleRepo.findById(roleId, workspaceId);
+    if (!role || !role.enabled) return null;
+    return role;
+  }
+
+  /**
+   * Resolve the public-share chat model BEFORE res.hijack() (clean 503 path).
+   * An admin-selected role's model override takes precedence over the cheap
+   * `publicShareChatModel`; without a role override it uses the cheap
+   * `publicShareChatModel`, falling back to the workspace `chatModel` when unset.
+   *
+   * IMPORTANT: a model override substitutes ONLY the model id (unless the role
+   * also switches the driver). The baseUrl and apiKey are reused from the
+   * workspace's main chat provider (see AiService.getChatModel) — the "cheap
+   * model" is NOT an isolated provider or key, just a different model on the SAME
+   * configured provider.
+   */
+  async getShareChatModel(
+    workspaceId: string,
+    role?: AiAgentRole | null,
+  ): Promise<LanguageModel> {
+    const override = roleModelOverride(role);
+    if (override) {
+      return this.ai.getChatModel(workspaceId, override);
+    }
     const resolved = await this.aiSettings.resolve(workspaceId);
     return this.ai.getChatModel(workspaceId, {
       chatModel: resolved?.publicShareChatModel,
@@ -142,6 +174,7 @@ export class PublicShareChatService {
     res,
     signal,
     model,
+    role,
   }: PublicShareChatStreamArgs): Promise<void> {
     // Rebuild the conversation from the client payload. The client holds the
     // transcript (ephemeral, never stored). Trusting it is safe: the share
@@ -153,6 +186,7 @@ export class PublicShareChatService {
     const system = buildShareSystemPrompt({
       share: { sharedPageTitle: share.sharedPage?.title ?? null },
       openedPage,
+      roleInstructions: role?.instructions ?? null,
     });
 
     // Tiny, READ-only, in-process toolset hard-scoped to THIS share tree.
diff --git a/apps/server/src/core/ai-chat/public-share-chat.spec.ts b/apps/server/src/core/ai-chat/public-share-chat.spec.ts
index f7d6f19f..623852fb 100644
--- a/apps/server/src/core/ai-chat/public-share-chat.spec.ts
+++ b/apps/server/src/core/ai-chat/public-share-chat.spec.ts
@@ -182,25 +182,55 @@ describe('buildShareSystemPrompt locking', () => {
     // Anti prompt-injection clause is present.
     expect(prompt).toContain('anti prompt-injection');
   });
+
+  it('a selected role REPLACES the persona but still appends the safety framework', () => {
+    const prompt = buildShareSystemPrompt({
+      share: null,
+      openedPage: null,
+      roleInstructions: 'You are Captain Docs.',
+    });
+    // The role's persona replaces the built-in one...
+    expect(prompt).toContain('Captain Docs');
+    // ...but the immutable safety clauses are still appended.
+    expect(prompt).toContain('read-only assistant');
+    expect(prompt).toContain('anti prompt-injection');
+  });
 });
 
 describe('PublicShareChatService model fallback', () => {
-  function makeService(resolvePublicModel: string | undefined) {
+  // `role` (optional) drives both the resolved settings (its id is returned as
+  // publicShareAssistantRoleId) and the role repo's findById mock, so the same
+  // helper exercises the no-role fallback AND the role-override paths.
+  function makeService(
+    resolvePublicModel: string | undefined,
+    role?: {
+      id: string;
+      name: string;
+      enabled: boolean;
+      instructions?: string;
+      modelConfig?: Record<string, unknown> | null;
+    },
+  ) {
     const aiSettings = {
-      resolve: jest
-        .fn()
-        .mockResolvedValue({ publicShareChatModel: resolvePublicModel }),
+      resolve: jest.fn().mockResolvedValue({
+        publicShareChatModel: resolvePublicModel,
+        publicShareAssistantRoleId: role ? role.id : undefined,
+      }),
     };
     const getChatModel = jest.fn().mockResolvedValue('MODEL');
     const ai = { getChatModel };
+    const aiAgentRoleRepo = {
+      findById: jest.fn().mockResolvedValue(role ?? undefined),
+    };
     const redisService = { getOrThrow: () => new FakeRedis() } as never;
     const service = new PublicShareChatService(
       ai as never,
       aiSettings as never,
       {} as never,
       redisService,
+      aiAgentRoleRepo as never,
     );
-    return { service, getChatModel };
+    return { service, getChatModel, aiAgentRoleRepo };
   }
 
   it('passes the cheap publicShareChatModel as the override', async () => {
@@ -216,6 +246,64 @@ describe('PublicShareChatService model fallback', () => {
     await service.getShareChatModel('ws-1');
     expect(getChatModel).toHaveBeenCalledWith('ws-1', { chatModel: undefined });
   });
+
+  describe('resolveShareRole', () => {
+    it('returns null when no roleId is configured', async () => {
+      const { service } = makeService('cheap-model');
+      expect(await service.resolveShareRole('ws-1')).toBeNull();
+    });
+
+    it('returns null when the configured role is disabled', async () => {
+      const { service } = makeService('cheap-model', {
+        id: 'r-1',
+        name: 'R',
+        enabled: false,
+      });
+      expect(await service.resolveShareRole('ws-1')).toBeNull();
+    });
+
+    it('returns null when findById resolves undefined (missing/soft-deleted)', async () => {
+      const { service, aiAgentRoleRepo } = makeService('cheap-model', {
+        id: 'r-1',
+        name: 'R',
+        enabled: true,
+      });
+      // The settings point at r-1, but the repo can no longer find it.
+      aiAgentRoleRepo.findById.mockResolvedValue(undefined);
+      expect(await service.resolveShareRole('ws-1')).toBeNull();
+    });
+
+    it('returns the role when it exists and is enabled', async () => {
+      const role = { id: 'r-1', name: 'R', enabled: true };
+      const { service } = makeService('cheap-model', role);
+      expect(await service.resolveShareRole('ws-1')).toEqual(role);
+    });
+  });
+
+  describe('getShareChatModel with a role', () => {
+    it('applies the role model override (takes precedence over the cheap model)', async () => {
+      const role = {
+        id: 'r-1',
+        name: 'R',
+        enabled: true,
+        modelConfig: { chatModel: 'role-model' },
+      };
+      const { service, getChatModel } = makeService('cheap-model', role);
+      await service.getShareChatModel('ws-1', role as never);
+      expect(getChatModel).toHaveBeenCalledWith(
+        'ws-1',
+        expect.objectContaining({ chatModel: 'role-model', roleName: 'R' }),
+      );
+    });
+
+    it('falls back to the publicShareChatModel override when role is null', async () => {
+      const { service, getChatModel } = makeService('cheap-model');
+      await service.getShareChatModel('ws-1', null);
+      expect(getChatModel).toHaveBeenCalledWith('ws-1', {
+        chatModel: 'cheap-model',
+      });
+    });
+  });
 });
 
 describe('PublicShareWorkspaceLimiter (cluster-wide sliding-window per-workspace cap)', () => {
@@ -315,6 +403,7 @@ describe('PublicShareChatService.tryConsumeWorkspaceQuota', () => {
       {} as never,
       {} as never,
       redisService,
+      {} as never,
     );
     // The default cap is high, so a couple of calls are allowed; this asserts
     // the service exposes the async limiter contour the controller relies on.
diff --git a/apps/server/src/database/repos/workspace/workspace.repo.ts b/apps/server/src/database/repos/workspace/workspace.repo.ts
index e2302208..821120f7 100644
--- a/apps/server/src/database/repos/workspace/workspace.repo.ts
+++ b/apps/server/src/database/repos/workspace/workspace.repo.ts
@@ -239,7 +239,7 @@ export class WorkspaceRepo {
     // is a real jsonb object, never a double-encoded string. The CASE self-heals
     // workspaces whose settings.ai.provider was previously corrupted into an
     // array/string.
-    const ALLOWED = ['driver', 'chatModel', 'embeddingModel', 'baseUrl', 'embeddingBaseUrl', 'sttModel', 'sttBaseUrl', 'sttApiStyle', 'systemPrompt', 'publicShareChatModel'];
+    const ALLOWED = ['driver', 'chatModel', 'embeddingModel', 'baseUrl', 'embeddingBaseUrl', 'sttModel', 'sttBaseUrl', 'sttApiStyle', 'systemPrompt', 'publicShareChatModel', 'publicShareAssistantRoleId'];
     const entries = Object.entries(provider).filter(
       ([k, v]) => v !== undefined && ALLOWED.includes(k),
     );
diff --git a/apps/server/src/integrations/ai/ai-settings.service.ts b/apps/server/src/integrations/ai/ai-settings.service.ts
index 2920b132..c5df5f45 100644
--- a/apps/server/src/integrations/ai/ai-settings.service.ts
+++ b/apps/server/src/integrations/ai/ai-settings.service.ts
@@ -34,6 +34,7 @@ export interface UpdateAiSettingsInput {
   sttApiStyle?: SttApiStyle;
   sttApiKey?: string;
   publicShareChatModel?: string;
+  publicShareAssistantRoleId?: string;
 }
 
 /**
@@ -135,6 +136,9 @@ export class AiSettingsService {
       // Cheap model id for the anonymous public-share assistant; reuses the chat
       // driver/baseUrl/apiKey. Empty/unset → callers fall back to chatModel.
       publicShareChatModel: provider.publicShareChatModel,
+      // Agent-role id whose persona the public-share assistant adopts; empty/unset
+      // = built-in locked persona.
+      publicShareAssistantRoleId: provider.publicShareAssistantRoleId,
       embeddingModel: provider.embeddingModel,
       sttModel: provider.sttModel,
       // Plain passthrough, no fallback; the transcribe path defaults unset to
@@ -216,6 +220,7 @@ export class AiSettingsService {
       sttApiStyle: provider.sttApiStyle,
       systemPrompt: provider.systemPrompt,
       publicShareChatModel: provider.publicShareChatModel,
+      publicShareAssistantRoleId: provider.publicShareAssistantRoleId,
       hasApiKey,
       hasEmbeddingApiKey,
       hasSttApiKey,
@@ -254,6 +259,7 @@ export class AiSettingsService {
       'sttApiStyle',
       'systemPrompt',
       'publicShareChatModel',
+      'publicShareAssistantRoleId',
     ] as const) {
       if (nonSecret[key] !== undefined) {
         (providerPatch as Record<string, unknown>)[key] = nonSecret[key];
diff --git a/apps/server/src/integrations/ai/ai.types.ts b/apps/server/src/integrations/ai/ai.types.ts
index 3fedd7ac..d6a70892 100644
--- a/apps/server/src/integrations/ai/ai.types.ts
+++ b/apps/server/src/integrations/ai/ai.types.ts
@@ -38,6 +38,9 @@ export interface AiProviderSettings {
   // `chatModel`. The workspace owner pays for anonymous tokens, so a cheaper
   // model is preferred for read-only Q&A over published documentation.
   publicShareChatModel?: string;
+  // Agent-role id whose persona the anonymous public-share assistant adopts;
+  // empty/unset = built-in locked persona.
+  publicShareAssistantRoleId?: string;
 }
 
 /**
@@ -55,6 +58,9 @@ export interface ResolvedAiConfig extends Partial<AiProviderSettings> {
   chatModel?: string;
   // Cheap model id for the public-share assistant; reuses the chat creds.
   publicShareChatModel?: string;
+  // Agent-role id whose persona the public-share assistant adopts (empty/unset
+  // = built-in locked persona). Re-declared for parity with the explicit fields.
+  publicShareAssistantRoleId?: string;
   apiKey?: string;
   embeddingApiKey?: string;
   sttApiKey?: string;
@@ -76,6 +82,9 @@ export interface MaskedAiSettings {
   sttApiStyle?: SttApiStyle;
   systemPrompt?: string;
   publicShareChatModel?: string;
+  // Agent-role id whose persona the public-share assistant adopts; empty/unset
+  // = built-in locked persona.
+  publicShareAssistantRoleId?: string;
   hasApiKey: boolean;
   hasEmbeddingApiKey: boolean;
   hasSttApiKey: boolean;
diff --git a/apps/server/src/integrations/ai/dto/update-ai-settings.dto.ts b/apps/server/src/integrations/ai/dto/update-ai-settings.dto.ts
index 40311e5e..891304ce 100644
--- a/apps/server/src/integrations/ai/dto/update-ai-settings.dto.ts
+++ b/apps/server/src/integrations/ai/dto/update-ai-settings.dto.ts
@@ -63,4 +63,10 @@ export class UpdateAiSettingsDto {
   @IsOptional()
   @IsString()
   publicShareChatModel?: string;
+
+  // Agent-role id whose persona the anonymous public-share assistant adopts;
+  // empty/unset = built-in locked persona.
+  @IsOptional()
+  @IsString()
+  publicShareAssistantRoleId?: string;
 }