test(ai-chat): safety-critical coverage + a11y + pure refactors

Unit tests for the safety-critical paths: crypto secret-box (round-trip,
tamper detection, wrong key), the SSRF guard (blocked ranges + DNS-rebinding),
the ai-chat tools service, the page-embedding repo, and the
assistant-parts/serialization helpers. Those server helpers (assistantParts,
rowToUiMessage, serializeSteps) are exported ONLY for the tests — no runtime
change.

Also: keyboard a11y on the chat history header and conversation rows
(role/tabIndex/Enter+Space), and DRY refactors that move shared logic into one
place (isToolPart -> tool-parts util; buildInitialValues in the MCP form).

The behaviour-changing edits that previously rode along in this commit are
split out into the following two commits, per review.

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

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

@@ -538,7 +538,9 @@ 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 this pure helper; exporting it
+// does not change runtime behavior.
+export function assistantParts(
   steps: ReadonlyArray<StepLike> | undefined,
   fallbackText: string,
 ): UIMessage['parts'] {
@@ -596,7 +598,7 @@ 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 +615,7 @@ 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/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/);
+  });
+});