test(ai-chat): cover crypto/SSRF/assistant-parts; a11y + refactors

Closes the ai-chat code-review follow-ups.

Tests (security-critical paths previously uncovered):
- secret-box.spec: AES-256-GCM round-trip, random-salt uniqueness, tampered
  blob / wrong APP_SECRET throw the expected message.
- ssrf-guard.spec: isIpAllowed blocks loopback/link-local/private/CGNAT/ULA/
  unspecified/IPv4-mapped, allows public; isUrlAllowed blocks bad scheme,
  invalid URL, IP literals, and DNS-rebinding (mocked dns.lookup).
- ai-chat.service.spec: assistantParts emits output-error for an UNPAIRED
  tool call (guards the MissingToolResultsError fix), output-available when
  paired, skips malformed calls; serializeSteps/rowToUiMessage.
- ai-chat-tools.service.spec: JSON-string node/content coercion + invalid-JSON
  throws; updatePageJson title-only vs object.
- page-embedding.repo.spec: empty spaceIds early-returns [] with no DB call.

a11y:
- Chat history toggle and conversation rows are now keyboard-operable
  (role=button, tabIndex, Enter/Space), matching history-item.tsx.

Refactors:
- onError on useChat adopts the server chat id when the first turn errors
  (AI SDK v6 onFinish doesn't fire on error).
- isToolPart exported once from tool-parts and shared (was duplicated).
- buildInitialValues() dedups the ai-mcp-server-form initial values.
- describeProviderError replaces two inline statusCode/message snippets.
- tool-parts stale tool-list comment refreshed.

Implements docs/backlog/ai-chat-review-followups.md.

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

apps/client/src/features/ai-chat/components/ai-chat-window.tsx

@@ -400,7 +400,16 @@ export default function AiChatWindow() {
           >
             <div
               className={classes.historyHeader}
+              role="button"
+              tabIndex={0}
+              aria-expanded={historyOpen}
               onClick={() => setHistoryOpen((o) => !o)}
+              onKeyDown={(event) => {
+                if (event.key === "Enter" || event.key === " ") {
+                  event.preventDefault();
+                  setHistoryOpen((o) => !o);
+                }
+              }}
             >
               <IconChevronDown
                 size={12}

apps/client/src/features/ai-chat/components/chat-thread.tsx

@@ -134,6 +134,13 @@ export default function ChatThread({
     messages: initialMessages,
     transport,
     onFinish: () => onTurnFinished(),
+    // In AI SDK v6 `onFinish` does NOT fire when the stream errors, so a brand
+    // new chat that fails on its first turn would never invalidate the chat list
+    // nor adopt the server-created chat id (the server still creates the row and
+    // saves the error message). Run the same post-turn path on error so the
+    // failed chat appears in history immediately instead of after a manual
+    // refresh. The error itself is still surfaced via `error` below.
+    onError: () => onTurnFinished(),
   });
 
   const isStreaming = status === "submitted" || status === "streaming";

apps/client/src/features/ai-chat/components/conversation-list.tsx

@@ -115,7 +115,17 @@ export default function ConversationList({
               classes.conversationItem,
               isActive && classes.conversationItemActive,
             )}
+            role="button"
+            tabIndex={0}
             onClick={() => onSelect(chat.id)}
+            onKeyDown={(e) => {
+              // Activate on Enter/Space like a native button; the inner menu
+              // button stops propagation so its own keys never reach this row.
+              if (e.key === "Enter" || e.key === " ") {
+                e.preventDefault();
+                onSelect(chat.id);
+              }
+            }}
           >
             <Text size="sm" lineClamp={1} style={{ flex: 1 }}>
               {chat.title || t("Untitled chat")}

apps/client/src/features/ai-chat/components/message-item.tsx

@@ -3,7 +3,7 @@ import { IconAlertTriangle } from "@tabler/icons-react";
 import { useTranslation } from "react-i18next";
 import type { UIMessage } from "@ai-sdk/react";
 import ToolCallCard from "@/features/ai-chat/components/tool-call-card.tsx";
-import { ToolUiPart } from "@/features/ai-chat/utils/tool-parts.tsx";
+import { ToolUiPart, isToolPart } from "@/features/ai-chat/utils/tool-parts.tsx";
 import { renderChatMarkdown } from "@/features/ai-chat/utils/markdown.ts";
 import { describeChatError } from "@/features/ai-chat/utils/error-message.ts";
 import classes from "@/features/ai-chat/components/ai-chat.module.css";
@@ -12,11 +12,6 @@ interface MessageItemProps {
   message: UIMessage;
 }
 
-/** True for AI SDK tool parts (static `tool-*` or `dynamic-tool`). */
-function isToolPart(type: string): boolean {
-  return type.startsWith("tool-") || type === "dynamic-tool";
-}
-
 /**
  * Render a single UIMessage by iterating its `parts`:
  *  - `text` parts -> sanitized markdown.

apps/client/src/features/ai-chat/components/message-list.tsx

@@ -4,6 +4,7 @@ import { useTranslation } from "react-i18next";
 import type { UIMessage } from "@ai-sdk/react";
 import MessageItem from "@/features/ai-chat/components/message-item.tsx";
 import TypingIndicator from "@/features/ai-chat/components/typing-indicator.tsx";
+import { isToolPart } from "@/features/ai-chat/utils/tool-parts.tsx";
 import classes from "@/features/ai-chat/components/ai-chat.module.css";
 
 interface MessageListProps {
@@ -11,11 +12,6 @@ interface MessageListProps {
   isStreaming: boolean;
 }
 
-/** True for AI SDK tool parts (static `tool-*` or `dynamic-tool`). */
-function isToolPart(type: string): boolean {
-  return type.startsWith("tool-") || type === "dynamic-tool";
-}
-
 // Distance (px) from the bottom within which the viewport still counts as
 // "pinned" — absorbs sub-pixel rounding and small content jitter.
 const BOTTOM_THRESHOLD = 40;

apps/client/src/features/ai-chat/utils/tool-parts.tsx

@@ -5,9 +5,11 @@
  *
  * A tool part's `type` is `tool-${toolName}` (AI SDK v6 static tool parts) and
  * its `state` is one of input-streaming / input-available / output-available /
- * output-error (we only surface running / done / error). The server tools are:
+ * output-error (we only surface running / done / error). The full toolset the
- * searchPages, getPage, createPage, updatePageContent, renamePage, movePage,
+ * server exposes lives in `ai-chat-tools.service.ts` (the agent now exposes the
- * deletePage, createComment, resolveComment — see ai-chat-tools.service.ts.
+ * complete Docmost toolset); friendly action-log labels exist ONLY for the
+ * tools listed in `toolLabelKey` below — every other tool falls through to the
+ * generic "Ran tool {{name}}" label.
  */
 
 /** A tool UI part as it arrives from `useChat` / persisted history. */
@@ -38,6 +40,11 @@ export interface ToolCitation {
   href: string;
 }
 
+/** True for AI SDK tool parts (static `tool-*` or `dynamic-tool`). */
+export function isToolPart(type: string): boolean {
+  return type.startsWith("tool-") || type === "dynamic-tool";
+}
+
 /** Extract the tool name from a part `type` of `tool-${name}` (or dynamic). */
 export function getToolName(part: ToolUiPart): string {
   if (part.type === "dynamic-tool") return part.toolName ?? "";

apps/client/src/features/workspace/components/settings/components/ai-mcp-server-form.tsx

@@ -47,6 +47,21 @@ interface AiMcpServerFormProps {
   onClose: () => void;
 }
 
+// Build the form's field values from a (possibly undefined) server. Used both
+// for the initial mount and for re-hydration when the modal is reused for a
+// different server, so the two stay in sync. authHeader is always empty: it is
+// a write-only secret buffer never echoed back from the server.
+function buildInitialValues(server?: IAiMcpServer): FormValues {
+  return {
+    name: server?.name ?? "",
+    transport: server?.transport ?? "http",
+    url: server?.url ?? "",
+    authHeader: "",
+    toolAllowlist: server?.toolAllowlist ?? [],
+    enabled: server?.enabled ?? true,
+  };
+}
+
 // Tavily preset (§8.10): the API key goes in the Authorization HEADER, not the URL.
 const TAVILY_PRESET = {
   name: "Tavily",
@@ -72,26 +87,12 @@ export default function AiMcpServerForm({
 
   const form = useForm<FormValues>({
     validate: zod4Resolver(formSchema),
-    initialValues: {
+    initialValues: buildInitialValues(server),
-      name: server?.name ?? "",
-      transport: server?.transport ?? "http",
-      url: server?.url ?? "",
-      authHeader: "",
-      toolAllowlist: server?.toolAllowlist ?? [],
-      enabled: server?.enabled ?? true,
-    },
   });
 
   // Re-hydrate when the target server changes (e.g. reusing the modal).
   useEffect(() => {
-    form.setValues({
+    form.setValues(buildInitialValues(server));
-      name: server?.name ?? "",
-      transport: server?.transport ?? "http",
-      url: server?.url ?? "",
-      authHeader: "",
-      toolAllowlist: server?.toolAllowlist ?? [],
-      enabled: server?.enabled ?? true,
-    });
     form.resetDirty();
     setHasHeaders(server?.hasHeaders ?? false);
     setHeadersCleared(false);

apps/server/src/core/ai-chat/ai-chat.service.spec.ts

@@ -1,4 +1,10 @@
-import { compactToolOutput } from './ai-chat.service';
+import {
+  compactToolOutput,
+  assistantParts,
+  serializeSteps,
+  rowToUiMessage,
+} from './ai-chat.service';
+import type { AiChatMessage } from '@docmost/db/types/entity.types';
 
 /**
  * Unit tests for compactToolOutput: the pure helper that shrinks LARGE tool
@@ -66,3 +72,121 @@ describe('compactToolOutput', () => {
     expect(compactedBytes).toBeLessThan(originalBytes / 10);
   });
 });
+
+/**
+ * Tests for assistantParts: the pure function that rebuilds the persisted
+ * UIMessage parts for a turn. Its output decides whether the conversation
+ * replays correctly on the next turn. The crux: a tool-call WITHOUT a paired
+ * result must become a synthetic `output-error` part, so convertToModelMessages
+ * never throws MissingToolResultsError. This test MUST fail on pre-fix logic
+ * that persisted a bare input-available call.
+ */
+describe('assistantParts', () => {
+  type AnyPart = Record<string, unknown>;
+
+  it('emits output-available for a tool-call WITH a paired result', () => {
+    const steps = [
+      {
+        text: '',
+        toolCalls: [{ toolCallId: 'c1', toolName: 'getPage', input: { id: 'p1' } }],
+        toolResults: [{ toolCallId: 'c1', toolName: 'getPage', output: { title: 'T' } }],
+      },
+    ];
+    const parts = assistantParts(steps, '') as AnyPart[];
+    const toolPart = parts.find((p) => p.type === 'tool-getPage');
+    expect(toolPart).toBeDefined();
+    expect(toolPart!.state).toBe('output-available');
+    expect(toolPart!.output).toEqual({ title: 'T' });
+  });
+
+  it('emits a synthetic output-error for an UNPAIRED tool-call (crux)', () => {
+    const steps = [
+      {
+        text: '',
+        toolCalls: [{ toolCallId: 'c9', toolName: 'insertNode', input: { node: {} } }],
+        toolResults: [],
+      },
+    ];
+    const parts = assistantParts(steps, '') as AnyPart[];
+    const toolPart = parts.find((p) => p.type === 'tool-insertNode');
+    expect(toolPart).toBeDefined();
+    // The unpaired call MUST become output-error (NOT input-available), so the
+    // rebuilt history is balanced for convertToModelMessages on the next turn.
+    expect(toolPart!.state).toBe('output-error');
+    expect(toolPart!.errorText).toBeTruthy();
+    expect(toolPart).not.toHaveProperty('output');
+  });
+
+  it('skips malformed tool-calls (missing toolName or toolCallId)', () => {
+    const steps = [
+      {
+        text: '',
+        toolCalls: [
+          { toolCallId: 'c1', input: {} }, // no toolName
+          { toolName: 'getPage', input: {} }, // no toolCallId
+        ],
+        toolResults: [],
+      },
+    ];
+    const parts = assistantParts(steps, '') as AnyPart[];
+    const toolParts = parts.filter(
+      (p) => typeof p.type === 'string' && (p.type as string).startsWith('tool-'),
+    );
+    expect(toolParts).toHaveLength(0);
+  });
+
+  it('uses per-step text when present', () => {
+    const steps = [{ text: 'hello', toolCalls: [], toolResults: [] }];
+    const parts = assistantParts(steps, 'fallback-ignored') as AnyPart[];
+    expect(parts).toEqual([{ type: 'text', text: 'hello' }]);
+  });
+
+  it('falls back to a single text part when no step text', () => {
+    const parts = assistantParts([], 'final answer') as AnyPart[];
+    expect(parts).toEqual([{ type: 'text', text: 'final answer' }]);
+  });
+});
+
+describe('serializeSteps', () => {
+  it('returns null when there are no calls or results', () => {
+    expect(serializeSteps([])).toBeNull();
+  });
+
+  it('flattens calls and results into a compact trace', () => {
+    const trace = serializeSteps([
+      {
+        toolCalls: [{ toolName: 'getPage', input: { id: 'p1' } }],
+        toolResults: [{ toolName: 'getPage', output: { title: 'T' } }],
+      },
+    ]) as Array<Record<string, unknown>>;
+    expect(trace).toHaveLength(2);
+    expect(trace[0]).toEqual({ toolName: 'getPage', input: { id: 'p1' } });
+    expect(trace[1]).toEqual({ toolName: 'getPage', output: { title: 'T' } });
+  });
+});
+
+describe('rowToUiMessage', () => {
+  it('prefers metadata.parts over content', () => {
+    const row = {
+      id: 'm1',
+      role: 'assistant',
+      content: 'plain text',
+      metadata: { parts: [{ type: 'text', text: 'rich part' }] },
+    } as unknown as AiChatMessage;
+    const ui = rowToUiMessage(row);
+    expect(ui.role).toBe('assistant');
+    expect(ui.parts).toEqual([{ type: 'text', text: 'rich part' }]);
+  });
+
+  it('falls back to a single text part from content when no metadata.parts', () => {
+    const row = {
+      id: 'm2',
+      role: 'user',
+      content: 'hi there',
+      metadata: null,
+    } as unknown as AiChatMessage;
+    const ui = rowToUiMessage(row);
+    expect(ui.role).toBe('user');
+    expect(ui.parts).toEqual([{ type: 'text', text: 'hi there' }]);
+  });
+});

apps/server/src/core/ai-chat/ai-chat.service.ts

@@ -10,6 +10,7 @@ import {
 } from 'ai';
 import { AiService } from '../../integrations/ai/ai.service';
 import { AiSettingsService } from '../../integrations/ai/ai-settings.service';
+import { describeProviderError } from '../../integrations/ai/ai-error.util';
 import { AiChatRepo } from '@docmost/db/repos/ai-chat/ai-chat.repo';
 import { AiChatMessageRepo } from '@docmost/db/repos/ai-chat/ai-chat-message.repo';
 import { User, Workspace, AiChatMessage } from '@docmost/db/types/entity.types';
@@ -271,15 +272,10 @@ export class AiChatService {
       onError: async ({ error }) => {
         // NestJS Logger.error(message, stack?, context?): pass the real message
         // (with statusCode when present) + the stack string, not the Error
-        // object, so the actual provider cause is clearly logged.
+        // object, so the actual provider cause is clearly logged. Reuse the
-        const e = error as {
+        // shared formatter so provider error formatting stays unified.
-          statusCode?: number;
+        const e = error as { stack?: string };
-          message?: string;
+        const errorText = describeProviderError(error, String(error));
-          stack?: string;
-        };
-        const errorText = e?.statusCode
-          ? `${e.statusCode}: ${e.message ?? String(error)}`
-          : (e?.message ?? String(error));
         this.logger.error(`AI chat stream error: ${errorText}`, e?.stack);
         // Persist whatever text we have (likely empty) so the turn is recorded,
         // and record the error text in metadata so it is visible in history.
@@ -340,10 +336,9 @@ export class AiChatService {
       result.pipeUIMessageStreamToResponse(res.raw, {
         headers: { 'X-Accel-Buffering': 'no' },
         onError: (error: unknown) => {
-          const e = error as { statusCode?: number; message?: string };
+          // Reuse the shared formatter so provider error formatting stays
-          return e?.statusCode
+          // unified between the log line and the streamed error message.
-            ? `${e.statusCode}: ${e.message}`
+          return describeProviderError(error, 'AI stream error');
-            : (e?.message ?? 'AI stream error');
         },
       });
 
@@ -538,7 +533,9 @@ function compactValue(value: unknown, depth: number): unknown {
  * recovers the name. Falls back to a single `text` part built from
  * `fallbackText` when the steps carry no text.
  */
-function assistantParts(
+// Exported only so the unit tests can import these pure helpers; exporting
+// them does not change runtime behavior.
+export function assistantParts(
   steps: ReadonlyArray<StepLike> | undefined,
   fallbackText: string,
 ): UIMessage['parts'] {
@@ -596,7 +593,7 @@ function assistantParts(
  * stored parts when available; assistant messages restore the reconstructable
  * parts from metadata, falling back to a single text part from `content`.
  */
-function rowToUiMessage(row: AiChatMessage): Omit<UIMessage, 'id'> & {
+export function rowToUiMessage(row: AiChatMessage): Omit<UIMessage, 'id'> & {
   id: string;
 } {
   const role = row.role === 'assistant' ? 'assistant' : 'user';
@@ -613,7 +610,7 @@ function rowToUiMessage(row: AiChatMessage): Omit<UIMessage, 'id'> & {
  * `tool_calls` column. Stores only what the UI action-log and history need —
  * never raw provider payloads or keys.
  */
-function serializeSteps(
+export function serializeSteps(
   steps: ReadonlyArray<{
     toolCalls?: ReadonlyArray<{ toolName?: string; input?: unknown }>;
     toolResults?: ReadonlyArray<{ toolName?: string; output?: unknown }>;

apps/server/src/core/ai-chat/external-mcp/ssrf-guard.spec.ts

@@ -0,0 +1,119 @@
+/**
+ * Unit tests for the SSRF guard protecting admin-configured external MCP URLs.
+ *
+ * `isIpAllowed` is pure/sync: every blocked address class must be rejected and a
+ * public address allowed. `isUrlAllowed` adds scheme/URL validation and, for
+ * hostnames, a DNS resolve + re-check (the DNS-rebinding defense): a name that
+ * resolves to a private address must be blocked. We mock `node:dns` `lookup`
+ * (the guard promisifies it) so the rebinding case is deterministic and offline.
+ */
+
+// Mock node:dns BEFORE importing the guard so promisify(lookup) wraps our mock.
+const lookupMock = jest.fn();
+jest.mock('node:dns', () => ({
+  __esModule: true,
+  lookup: (...args: unknown[]) => lookupMock(...args),
+}));
+
+import { isIpAllowed, isUrlAllowed } from './ssrf-guard';
+
+// The guard calls promisify(lookup): our mock must honour the (host, opts, cb)
+// callback signature. Helper to make it resolve to a given address list.
+function dnsResolvesTo(addresses: { address: string }[]) {
+  lookupMock.mockImplementation(
+    (_host: string, _opts: unknown, cb: (e: unknown, a: unknown) => void) => {
+      cb(null, addresses);
+    },
+  );
+}
+
+describe('isIpAllowed', () => {
+  const blocked: Array<[string, string]> = [
+    ['loopback IPv4', '127.0.0.1'],
+    ['loopback IPv6', '::1'],
+    ['link-local / metadata', '169.254.169.254'],
+    ['private 10/8', '10.0.0.1'],
+    ['private 172.16/12', '172.16.5.4'],
+    ['private 192.168/16', '192.168.1.1'],
+    ['CGNAT 100.64/10', '100.64.1.1'],
+    ['ULA fc00::/7', 'fc00::1'],
+    ['unspecified IPv4', '0.0.0.0'],
+    ['unspecified IPv6', '::'],
+    ['IPv4-mapped IPv6 (private)', '::ffff:10.0.0.1'],
+  ];
+
+  it.each(blocked)('blocks %s (%s)', (_label, ip) => {
+    expect(isIpAllowed(ip).ok).toBe(false);
+  });
+
+  it('allows a public IPv4 (8.8.8.8)', () => {
+    expect(isIpAllowed('8.8.8.8').ok).toBe(true);
+  });
+
+  it('allows a public IPv6', () => {
+    expect(isIpAllowed('2001:4860:4860::8888').ok).toBe(true);
+  });
+
+  it('blocks an unparseable IP', () => {
+    expect(isIpAllowed('not-an-ip').ok).toBe(false);
+  });
+});
+
+describe('isUrlAllowed', () => {
+  beforeEach(() => {
+    lookupMock.mockReset();
+  });
+
+  it('blocks a non-http(s) scheme', async () => {
+    const res = await isUrlAllowed('ftp://example.com/');
+    expect(res.ok).toBe(false);
+    expect(lookupMock).not.toHaveBeenCalled();
+  });
+
+  it('blocks an invalid URL', async () => {
+    const res = await isUrlAllowed('::: not a url :::');
+    expect(res.ok).toBe(false);
+    expect(lookupMock).not.toHaveBeenCalled();
+  });
+
+  it('blocks a private IP literal host without DNS', async () => {
+    const res = await isUrlAllowed('http://169.254.169.254/latest/meta-data/');
+    expect(res.ok).toBe(false);
+    expect(lookupMock).not.toHaveBeenCalled();
+  });
+
+  it('blocks a bracketed private IPv6 literal host', async () => {
+    const res = await isUrlAllowed('http://[::1]:8080/');
+    expect(res.ok).toBe(false);
+    expect(lookupMock).not.toHaveBeenCalled();
+  });
+
+  it('blocks a hostname that resolves to a private address (DNS rebinding)', async () => {
+    dnsResolvesTo([{ address: '10.0.0.5' }]);
+    const res = await isUrlAllowed('http://rebind.example.com/');
+    expect(res.ok).toBe(false);
+    expect(lookupMock).toHaveBeenCalled();
+  });
+
+  it('blocks when ANY resolved address is private (mixed result)', async () => {
+    dnsResolvesTo([{ address: '8.8.8.8' }, { address: '127.0.0.1' }]);
+    const res = await isUrlAllowed('http://mixed.example.com/');
+    expect(res.ok).toBe(false);
+  });
+
+  it('allows a hostname that resolves only to a public address', async () => {
+    dnsResolvesTo([{ address: '8.8.8.8' }]);
+    const res = await isUrlAllowed('https://public.example.com/mcp');
+    expect(res.ok).toBe(true);
+  });
+
+  it('blocks when the host does not resolve', async () => {
+    lookupMock.mockImplementation(
+      (_host: string, _opts: unknown, cb: (e: unknown, a: unknown) => void) => {
+        cb(new Error('ENOTFOUND'), undefined);
+      },
+    );
+    const res = await isUrlAllowed('http://nonexistent.invalid/');
+    expect(res.ok).toBe(false);
+  });
+});

apps/server/src/core/ai-chat/tools/ai-chat-tools.service.spec.ts

@@ -211,3 +211,174 @@ describe('AiChatToolsService expanded toolset guardrails', () => {
     expect(parsed).not.toHaveProperty('deleteComments');
   });
 });
+
+/**
+ * JSON-string coercion for node arguments (fix 59b99dba): under OpenAI tool
+ * calls the model sometimes serializes `node`/`content` as a JSON STRING. The
+ * tools parse a string into an object before forwarding it to the client (which
+ * type-checks for an object), throw a documented message on invalid JSON, and
+ * `updatePageJson` distinguishes undefined (title-only) from object/string.
+ */
+describe('AiChatToolsService node-arg JSON-string coercion', () => {
+  // Records the positional args forwarded to each write method so we can assert
+  // the coerced (parsed) value reaches the client.
+  const patchNodeCalls: unknown[][] = [];
+  const insertNodeCalls: unknown[][] = [];
+  const updatePageJsonCalls: unknown[][] = [];
+
+  const fakeClient: Partial<DocmostClientLike> = {
+    patchNode: (...args: unknown[]) => {
+      patchNodeCalls.push(args);
+      return Promise.resolve({ ok: true });
+    },
+    insertNode: (...args: unknown[]) => {
+      insertNodeCalls.push(args);
+      return Promise.resolve({ ok: true });
+    },
+    updatePageJson: (...args: unknown[]) => {
+      updatePageJsonCalls.push(args);
+      return Promise.resolve({ ok: true });
+    },
+  };
+
+  const tokenServiceStub = {
+    generateAccessToken: jest.fn().mockResolvedValue('access-token'),
+    generateCollabToken: jest.fn().mockResolvedValue('collab-token'),
+  };
+
+  let service: AiChatToolsService;
+
+  beforeEach(() => {
+    patchNodeCalls.length = 0;
+    insertNodeCalls.length = 0;
+    updatePageJsonCalls.length = 0;
+    jest.spyOn(loader, 'loadDocmostMcp').mockResolvedValue({
+      DocmostClient: function () {
+        return fakeClient as DocmostClientLike;
+      } as unknown as loader.DocmostClientCtor,
+    });
+    service = new AiChatToolsService(
+      tokenServiceStub as never,
+      {} as never,
+      {} as never,
+      {} as never,
+      {} as never,
+    );
+  });
+
+  afterEach(() => {
+    jest.restoreAllMocks();
+  });
+
+  function buildTools() {
+    return service.forUser(
+      { id: 'user-1', email: 'u@example.com', workspaceId: 'ws-1' } as never,
+      'session-1',
+      'ws-1',
+      'chat-1',
+    );
+  }
+
+  const NODE_OBJ = {
+    type: 'paragraph',
+    content: [{ type: 'text', text: 'Hello' }],
+  };
+
+  it('patchNode parses a JSON-string node and forwards it as an object', async () => {
+    const tools = await buildTools();
+    await tools.patchNode.execute(
+      { pageId: 'p1', nodeId: 'n1', node: JSON.stringify(NODE_OBJ) } as never,
+      {} as never,
+    );
+    expect(patchNodeCalls).toHaveLength(1);
+    expect(patchNodeCalls[0]).toEqual(['p1', 'n1', NODE_OBJ]);
+  });
+
+  it('patchNode passes an object node through unchanged', async () => {
+    const tools = await buildTools();
+    await tools.patchNode.execute(
+      { pageId: 'p1', nodeId: 'n1', node: NODE_OBJ } as never,
+      {} as never,
+    );
+    expect(patchNodeCalls[0]).toEqual(['p1', 'n1', NODE_OBJ]);
+  });
+
+  it('patchNode throws the documented message on invalid JSON string', async () => {
+    const tools = await buildTools();
+    await expect(
+      tools.patchNode.execute(
+        { pageId: 'p1', nodeId: 'n1', node: '{not json' } as never,
+        {} as never,
+      ),
+    ).rejects.toThrow('node was a string but not valid JSON');
+    expect(patchNodeCalls).toHaveLength(0);
+  });
+
+  it('insertNode parses a JSON-string node and forwards it as an object', async () => {
+    const tools = await buildTools();
+    await tools.insertNode.execute(
+      {
+        pageId: 'p1',
+        node: JSON.stringify(NODE_OBJ),
+        position: 'append',
+      } as never,
+      {} as never,
+    );
+    expect(insertNodeCalls).toHaveLength(1);
+    const [pageId, node] = insertNodeCalls[0];
+    expect(pageId).toBe('p1');
+    expect(node).toEqual(NODE_OBJ);
+  });
+
+  it('insertNode throws the documented message on invalid JSON string', async () => {
+    const tools = await buildTools();
+    await expect(
+      tools.insertNode.execute(
+        { pageId: 'p1', node: 'nope', position: 'append' } as never,
+        {} as never,
+      ),
+    ).rejects.toThrow('node was a string but not valid JSON');
+    expect(insertNodeCalls).toHaveLength(0);
+  });
+
+  it('updatePageJson forwards doc=undefined for a title-only update (content undefined)', async () => {
+    const tools = await buildTools();
+    await tools.updatePageJson.execute(
+      { pageId: 'p1', title: 'New title' } as never,
+      {} as never,
+    );
+    expect(updatePageJsonCalls).toHaveLength(1);
+    expect(updatePageJsonCalls[0]).toEqual(['p1', undefined, 'New title']);
+  });
+
+  it('updatePageJson passes an object content through unchanged', async () => {
+    const tools = await buildTools();
+    const doc = { type: 'doc', content: [] };
+    await tools.updatePageJson.execute(
+      { pageId: 'p1', content: doc } as never,
+      {} as never,
+    );
+    expect(updatePageJsonCalls[0]).toEqual(['p1', doc, undefined]);
+  });
+
+  it('updatePageJson parses a JSON-string content', async () => {
+    const tools = await buildTools();
+    const doc = { type: 'doc', content: [] };
+    await tools.updatePageJson.execute(
+      { pageId: 'p1', content: JSON.stringify(doc) } as never,
+      {} as never,
+    );
+    expect(updatePageJsonCalls[0]).toEqual(['p1', doc, undefined]);
+  });
+
+  it('updatePageJson throws the documented message on invalid JSON string content', async () => {
+    const tools = await buildTools();
+    await expect(
+      tools.updatePageJson.execute(
+        { pageId: 'p1', content: '{bad' } as never,
+        {} as never,
+      ),
+    ).rejects.toThrow('content was a string but not valid JSON');
+    expect(updatePageJsonCalls).toHaveLength(0);
+  });
+});

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

@@ -0,0 +1,26 @@
+import { PageEmbeddingRepo } from './page-embedding.repo';
+import type { KyselyDB } from '../../types/kysely.types';
+
+/**
+ * Unit test for the pure access-scoping branch of searchByEmbedding: when the
+ * caller has NO accessible spaces (`spaceIds` empty), the method must early-
+ * return [] WITHOUT touching the database. We inject a db whose query builder
+ * throws if invoked, so any DB access fails the test.
+ *
+ * NOTE: the dimension-mixing case (filter by model_dimensions) needs a live
+ * pgvector-enabled Postgres and is intentionally NOT covered here — it requires
+ * a real DB and is out of scope for this pure unit test.
+ */
+describe('PageEmbeddingRepo.searchByEmbedding', () => {
+  it('early-returns [] for empty spaceIds without any DB call', async () => {
+    const throwingDb = {
+      selectFrom: () => {
+        throw new Error('DB should not be queried for empty spaceIds');
+      },
+    } as unknown as KyselyDB;
+
+    const repo = new PageEmbeddingRepo(throwingDb);
+    const result = await repo.searchByEmbedding('ws-1', [0.1, 0.2, 0.3], [], 10);
+    expect(result).toEqual([]);
+  });
+});

apps/server/src/integrations/ai/ai-error.util.ts

@@ -9,10 +9,16 @@
  *
  * None of these fields contain the API key (it is sent as an Authorization
  * header and never echoed in the response body), so this is safe to log/return.
+ *
+ * `fallback` is used when the error carries no usable message (e.g. a bare
+ * object); defaults to 'Unknown error'.
  */
-export function describeProviderError(err: unknown): string {
+export function describeProviderError(
+  err: unknown,
+  fallback = 'Unknown error',
+): string {
   if (typeof err !== 'object' || err === null) {
-    return typeof err === 'string' ? err : 'Unknown error';
+    return typeof err === 'string' && err ? err : fallback;
   }
   const e = err as {
     statusCode?: number;
@@ -23,7 +29,7 @@ export function describeProviderError(err: unknown): string {
   const base =
     typeof e.statusCode === 'number'
       ? `${e.statusCode}: ${e.message ?? ''}`.trim()
-      : (e.message ?? 'Unknown error');
+      : (e.message ?? fallback);
   const body = (e.responseBody ?? e.text ?? '').trim();
   if (!body) return base;
   // Collapse whitespace so a multi-line HTML body stays on one log line.

apps/server/src/integrations/crypto/secret-box.spec.ts

@@ -0,0 +1,77 @@
+import { SecretBoxService } from './secret-box';
+import { EnvironmentService } from '../environment/environment.service';
+
+/**
+ * Unit tests for SecretBoxService: the AES-256-GCM helper that protects provider
+ * API keys at rest. The contract is: encrypt -> decrypt round-trips the input;
+ * two encryptions of the same input yield different blobs (random salt+iv) yet
+ * both decrypt; a tampered blob or a different APP_SECRET fails decryption with
+ * the recoverable "APP_SECRET may have changed" message the UI relies on.
+ */
+describe('SecretBoxService', () => {
+  // Construct a SecretBoxService whose EnvironmentService.getAppSecret returns a
+  // fixed 64-hex secret. Only getAppSecret is exercised, so a thin fake suffices.
+  function makeBox(appSecret: string): SecretBoxService {
+    const env = {
+      getAppSecret: () => appSecret,
+    } as unknown as EnvironmentService;
+    return new SecretBoxService(env);
+  }
+
+  const SECRET_A =
+    '00112233445566778899aabbccddeeff00112233445566778899aabbccddeeff';
+  const SECRET_B =
+    'ffeeddccbbaa99887766554433221100ffeeddccbbaa99887766554433221100';
+
+  it('round-trips: decrypt(encrypt(x)) === x', () => {
+    const box = makeBox(SECRET_A);
+    const plain = 'sk-super-secret-provider-key-12345';
+    const blob = box.encryptSecret(plain);
+    expect(box.decryptSecret(blob)).toBe(plain);
+  });
+
+  it('produces a different blob each time, both of which decrypt', () => {
+    const box = makeBox(SECRET_A);
+    const plain = 'identical-input';
+    const blob1 = box.encryptSecret(plain);
+    const blob2 = box.encryptSecret(plain);
+    // Random per-record salt + iv => the ciphertext blobs must differ.
+    expect(blob1).not.toBe(blob2);
+    expect(box.decryptSecret(blob1)).toBe(plain);
+    expect(box.decryptSecret(blob2)).toBe(plain);
+  });
+
+  it('throws the recoverable error on a tampered auth tag', () => {
+    const box = makeBox(SECRET_A);
+    const blob = box.encryptSecret('tamper-me');
+
+    // Layout: base64( salt[16] | iv[12] | authTag[16] | ciphertext ). Flip a bit
+    // in the auth-tag region so GCM verification (decipher.final) rejects it.
+    const data = Buffer.from(blob, 'base64');
+    const authTagByteIndex = 16 + 12; // first byte of the auth tag
+    data[authTagByteIndex] = data[authTagByteIndex] ^ 0xff;
+    const tampered = data.toString('base64');
+
+    expect(() => box.decryptSecret(tampered)).toThrow(/APP_SECRET may have changed/);
+  });
+
+  it('throws the recoverable error on a tampered ciphertext byte', () => {
+    const box = makeBox(SECRET_A);
+    const blob = box.encryptSecret('tamper-the-body');
+
+    const data = Buffer.from(blob, 'base64');
+    // Last byte is part of the ciphertext; flipping it must fail GCM auth.
+    data[data.length - 1] = data[data.length - 1] ^ 0xff;
+    const tampered = data.toString('base64');
+
+    expect(() => box.decryptSecret(tampered)).toThrow(/APP_SECRET may have changed/);
+  });
+
+  it('throws when decrypting under a different APP_SECRET', () => {
+    const boxA = makeBox(SECRET_A);
+    const boxB = makeBox(SECRET_B);
+    const blob = boxA.encryptSecret('rotate-me');
+    // A different APP_SECRET derives a different scrypt key => GCM auth fails.
+    expect(() => boxB.decryptSecret(blob)).toThrow(/APP_SECRET may have changed/);
+  });
+});