fix(mcp): security review follow-ups (#24)

Post-merge hardening from the #13 security review:
- isInitializeRequestBody now delegates to the SDK isInitializeRequest (same
  predicate as packages/mcp/http.ts), so a bare {method:'initialize'} with no
  id/params no longer triggers the side-effecting login() (audit-spam /
  user_sessions growth) before http.ts 400s it.
- Bind the Bearer path to the instance workspace: verifyBearerAccess rejects a
  token whose payload.workspaceId != the instance workspace (resolved via
  workspaceRepo.findFirst, consistent with the Basic path); optional param so
  it's a no-op when unset.
- Close the user-enumeration timing oracle in verifyUserCredentials: the
  missing/disabled branch now runs a bcrypt compare against a module-level dummy
  hash whose cost (12) matches production saltRounds, so both paths take one
  equal-cost bcrypt compare; the exact CREDENTIALS_MISMATCH_MESSAGE is preserved.
- Document the trusted-proxy requirement for the spoofable per-IP brute-force
  limiter in .env.example (trustProxy is on; deploy behind a trusted proxy).
- Add real-execution coverage for enforceBasicLoginGate (SSO enforced / EE-MFA
  bundled vs not / user-MFA / workspace-enforced-MFA) instead of stubbing the gate.

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

.env.example

@@ -2,6 +2,16 @@
 APP_URL=http://localhost:3000
 PORT=3000
 
+# --- Security / reverse proxy ---
+# The app runs with Fastify `trustProxy` ENABLED, so it derives the client IP
+# (req.ip) from the `X-Forwarded-For` header. That header is client-forgeable.
+# Deploy this app behind a trusted reverse proxy that SETS/OVERWRITES (not
+# appends) `X-Forwarded-For` with the real client IP. Without such a proxy, any
+# per-IP throttling — including the /mcp Basic brute-force limiter — can be
+# bypassed by an attacker who simply spoofs `X-Forwarded-For` to rotate IPs.
+# (The /mcp limiter keeps a global per-email key as an IP-independent backstop,
+# but the per-IP and per-IP+email keys rely on a trustworthy X-Forwarded-For.)
+
 # minimum of 32 characters. Generate one with: openssl rand -hex 32
 APP_SECRET=REPLACE_WITH_LONG_SECRET
 

apps/server/src/core/auth/services/auth.service.ts

@@ -41,6 +41,20 @@ import {
 } from '../../../integrations/audit/audit.service';
 import { EnvironmentService } from '../../../integrations/environment/environment.service';
 
+// A valid bcrypt hash (cost 10, of an arbitrary throwaway string) used ONLY to
+// equalize timing in verifyUserCredentials: when the email does not exist or
+// the user is disabled, we still run ONE bcrypt comparison against this hash
+// before throwing, so the missing/disabled path takes about the same time as
+// the real-user wrong-password path. Without it, the "no bcrypt at all" branch
+// returns measurably faster, leaking whether an email is registered (a user-
+// enumeration timing oracle, now reachable via /mcp where throttling is only a
+// spoofable in-memory limiter). This is never used as a real credential.
+// The cost factor MUST match the production saltRounds (12 — see
+// common/helpers/utils.ts hashPassword), otherwise the dummy compare runs
+// faster than a real wrong-password compare and the timing oracle survives.
+const DUMMY_PASSWORD_HASH =
+  '$2b$12$q/l637TULK3vU3Cmji0y8utpJS/UiftMi3Jdm4Tsi5EIv/0FE7WV.';
+
 @Injectable()
 export class AuthService {
   constructor(
@@ -82,6 +96,12 @@ export class AuthService {
     // recognises this exact message via isCredentialsFailure.
     const errorMessage = CREDENTIALS_MISMATCH_MESSAGE;
     if (!user || isUserDisabled(user)) {
+      // Constant-time intent: run ONE bcrypt comparison (against a dummy hash)
+      // even when the user is missing/disabled, so this path takes about the
+      // same time as the real-user wrong-password path below. This closes the
+      // user-enumeration timing oracle (registered vs. not). The result is
+      // intentionally discarded — we always throw the same credentials error.
+      await comparePasswordHash(loginDto.password, DUMMY_PASSWORD_HASH);
       throw new UnauthorizedException(errorMessage);
     }
 

apps/server/src/core/auth/services/verify-user-credentials.contract.spec.ts

@@ -100,4 +100,40 @@ describe('AuthService no-side-effect contract (item 4)', () => {
       expect(verifyBody.includes(effect)).toBe(false);
     }
   });
+
+  // Item 4: user-enumeration timing-oracle fix. When the email is missing or the
+  // user is disabled, verifyUserCredentials must still run ONE bcrypt comparison
+  // (against a dummy hash) BEFORE throwing, so the missing/disabled path takes
+  // about the same time as the real-user wrong-password path. Asserted at the
+  // source level for the same reason as the rest of this file: AuthService cannot
+  // be imported under this jest config to spy on comparePasswordHash live.
+  describe('constant-time missing/disabled branch (item 4)', () => {
+    // Isolate the body of the `if (!user || isUserDisabled(user)) { ... }` guard.
+    const guardMatch = verifyBody.match(
+      /if \(!user \|\| isUserDisabled\(user\)\) \{([\s\S]*?)\n {4}\}/,
+    );
+
+    it('the missing/disabled guard runs a bcrypt compare before throwing', () => {
+      expect(guardMatch).not.toBeNull();
+      const guardBody = guardMatch![1];
+      // It performs the dummy bcrypt comparison...
+      expect(guardBody).toContain('comparePasswordHash');
+      // ...and only AFTER that throws the credentials error (compare precedes
+      // the throw STATEMENT — match `throw new`, not the word "throw" in a comment).
+      const compareIdx = guardBody.indexOf('comparePasswordHash');
+      const throwIdx = guardBody.indexOf('throw new');
+      expect(compareIdx).toBeGreaterThanOrEqual(0);
+      expect(throwIdx).toBeGreaterThan(compareIdx);
+    });
+
+    it('uses a module-level dummy hash constant (never a real credential)', () => {
+      // The dummy hash is a module-level constant referenced in the guard, not an
+      // inline literal recomputed per call.
+      expect(verifyBody).toContain('DUMMY_PASSWORD_HASH');
+      // Cost factor MUST be 12 to match production saltRounds, otherwise the
+      // dummy compare is faster than a real wrong-password compare and the
+      // timing oracle survives.
+      expect(source).toMatch(/const DUMMY_PASSWORD_HASH =\s*'\$2b\$12\$/);
+    });
+  });
 });

apps/server/src/integrations/mcp/mcp-auth.helpers.ts

@@ -5,6 +5,7 @@
 // the Authorization header.
 import { UnauthorizedException } from '@nestjs/common';
 import { timingSafeEqual } from 'node:crypto';
+import { isInitializeRequest } from '@modelcontextprotocol/sdk/types.js';
 import { JwtType } from '../../core/auth/dto/jwt-payload';
 import { CREDENTIALS_MISMATCH_MESSAGE } from '../../core/auth/auth.constants';
 
@@ -291,6 +292,14 @@ export interface BearerVerifyDeps {
     workspaceId?: string;
     sessionId?: string;
   }>;
+  // The workspace id of THIS MCP instance, when the caller can resolve it (the
+  // community build is single-workspace, so McpService passes its default
+  // workspace's id). When provided, the token's `workspaceId` claim MUST equal
+  // it, mirroring JwtStrategy's `req.raw.workspaceId !== payload.workspaceId`
+  // guard so a valid ACCESS token from a DIFFERENT workspace cannot be replayed
+  // against this instance in a multi-workspace deployment. Optional so callers /
+  // tests that genuinely cannot resolve an instance workspace are unchanged.
+  expectedWorkspaceId?: string;
   // Load the user (or undefined) for the disabled check.
   findUser: (
     sub: string,
@@ -321,6 +330,19 @@ export async function verifyBearerAccess(
     throw new UnauthorizedException(generic);
   }
 
+  // Bind the token to THIS instance's workspace (mirrors JwtStrategy). When the
+  // caller resolved an instance workspace id, a token whose `workspaceId` claim
+  // points at another workspace is rejected, so a valid ACCESS token minted in
+  // workspace B cannot be replayed against an MCP instance serving workspace A.
+  // In the single-workspace community build expectedWorkspaceId equals the only
+  // workspace, so this is a no-op there; it only bites a multi-workspace deploy.
+  if (
+    deps.expectedWorkspaceId &&
+    payload.workspaceId !== deps.expectedWorkspaceId
+  ) {
+    throw new UnauthorizedException(generic);
+  }
+
   const user = await deps.findUser(payload.sub, payload.workspaceId);
   if (!user || user.deactivatedAt || user.deletedAt) {
     throw new UnauthorizedException(generic);
@@ -342,21 +364,24 @@ export async function verifyBearerAccess(
 
 /**
  * Detect a genuine JSON-RPC `initialize` request from an already-parsed body.
- * Mirrors the @modelcontextprotocol/sdk `isInitializeRequest` signal that
+ * Delegates to the @modelcontextprotocol/sdk `isInitializeRequest` predicate —
- * packages/mcp/src/http.ts uses to decide whether to mint a session, but
+ * the SAME predicate packages/mcp/src/http.ts uses to decide whether to mint a
- * framework/SDK-free so it is unit-testable and usable from the CommonJS
+ * session — so the session-minting side (this server) and the session-creating
- * McpService. An initialize request is a single JSON-RPC object whose `method`
+ * side (http.ts) agree EXACTLY on what counts as an initialize request. The SDK
- * is exactly 'initialize'; a batch (array) body is never an initialize request.
+ * predicate validates the full InitializeRequest shape (jsonrpc, id, method ===
+ * 'initialize', params incl. protocolVersion); a bare `{ method: 'initialize' }`
+ * with no params, a batch (array) body, etc. are NOT initialize requests.
  *
  * This is the second half of the session-INIT decision: `isSessionInit` is
- * (no `mcp-session-id` header) AND `isInitializeRequestBody(body)`. Using it
+ * (no `mcp-session-id` header) AND `isInitializeRequestBody(body)`. Matching the
- * ensures the side-effecting login() (user_sessions insert + USER_LOGIN audit +
+ * SDK predicate exactly ensures the side-effecting login() (user_sessions insert
- * lastLoginAt) only runs for a real initialize, never for an arbitrary
+ * + USER_LOGIN audit + lastLoginAt) only runs for a request http.ts will also
- * header-less request that http.ts will subsequently 400.
+ * accept as an initialize — never for an arbitrary header-less request that
+ * http.ts would subsequently 400 (which would otherwise spam the audit log /
+ * grow user_sessions without ever creating an MCP session).
  */
 export function isInitializeRequestBody(body: unknown): boolean {
-  if (!body || typeof body !== 'object' || Array.isArray(body)) return false;
+  return isInitializeRequest(body);
-  return (body as { method?: unknown }).method === 'initialize';
 }
 
 /** Extract a Bearer token from an Authorization header (case-insensitive). */

apps/server/src/integrations/mcp/mcp-basic-login-gate.spec.ts

@@ -0,0 +1,253 @@
+import { UnauthorizedException } from '@nestjs/common';
+
+// ---------------------------------------------------------------------------
+// These tests exercise the REAL McpService.enforceBasicLoginGate (the pre-token
+// SSO/MFA gate on the /mcp HTTP-Basic path). Unlike the resolveMcpSessionConfig
+// tests in mcp.service.spec.ts — which STUB the gate and only assert it runs
+// before login()/verifyCredentials — here the gate logic is instantiated for
+// real and only its LEAF dependencies are mocked:
+//   - the workspace object (plain object with/without enforceSso),
+//   - the user credentials (plain object),
+//   - the lazily-required EE MFA module (jest.mock with { virtual: true } so we
+//     can simulate BOTH "bundled" and "not bundled" community-build states),
+//   - the injected MfaService instance (via a stub moduleRef).
+//
+// McpService cannot normally be imported under jest because it imports
+// AuthService, which drags in the React email-template graph
+// (@docmost/transactional/emails/*) that the jest moduleNameMapper does not
+// resolve. We therefore mock the heavy collaborator modules (auth.service,
+// token.service, the @docmost/db repos and mcp-auth.helpers) at the module
+// level so importing mcp.service.ts succeeds. None of those are touched by the
+// gate itself, so the gate runs unmodified against the real code path.
+// ---------------------------------------------------------------------------
+
+// The EE MFA module specifier the jest.mock below intercepts MUST be
+// byte-for-byte the specifier that mcp.service.ts lazily require()s
+// ('./../../ee/mfa/services/mfa.service'). jest.mock is hoisted above all
+// non-hoisted code, so the path is inlined as a literal in the call below
+// rather than referenced through a const (which would not yet be initialised).
+// `{ virtual: true }` is required because the EE module does not exist in this
+// OSS build (there is no src/ee directory) — without it jest cannot register a
+// mock for a path it cannot resolve on disk.
+
+// Mutable handle the virtual mock factory reads, so each test can decide whether
+// the EE module is "bundled" (factory returns a MfaService class) or "not
+// bundled" (factory throws, mimicking the require() failing on a community
+// build). jest.mock is hoisted, so the factory must close over this lazily.
+let mfaModuleState: { bundled: boolean; checkMfaRequirements?: jest.Mock } = {
+  bundled: false,
+};
+
+jest.mock(
+  './../../ee/mfa/services/mfa.service',
+  () => {
+    if (!mfaModuleState.bundled) {
+      // Simulate a community/fork build with no EE MFA module: the real
+      // require() throws, which the gate catches as the "no MFA gate" path.
+      throw new Error('Cannot find module (EE MFA not bundled)');
+    }
+    // "Bundled" build: expose a MfaService class token. The actual instance the
+    // gate calls is resolved through moduleRef.get(MfaModule.MfaService), which
+    // our stub moduleRef returns regardless of the token identity.
+    class MfaService {}
+    return { MfaService };
+  },
+  { virtual: true },
+);
+
+// --- Mock the heavy collaborator modules so importing mcp.service succeeds. ---
+// The gate never calls into these; they exist only to satisfy the import graph.
+jest.mock('../../core/auth/services/auth.service', () => ({
+  AuthService: class AuthService {},
+}));
+jest.mock('../../core/auth/services/token.service', () => ({
+  TokenService: class TokenService {},
+}));
+jest.mock('@docmost/db/repos/workspace/workspace.repo', () => ({
+  WorkspaceRepo: class WorkspaceRepo {},
+}));
+jest.mock('@docmost/db/repos/user/user.repo', () => ({
+  UserRepo: class UserRepo {},
+}));
+jest.mock('@docmost/db/repos/session/user-session.repo', () => ({
+  UserSessionRepo: class UserSessionRepo {},
+}));
+// mcp-auth.helpers exports both runtime values (FailedLoginLimiter is used in
+// the constructor) and types. Provide a minimal FailedLoginLimiter so the
+// constructor runs; everything else the gate path doesn't need.
+jest.mock('./mcp-auth.helpers', () => ({
+  FailedLoginLimiter: class FailedLoginLimiter {
+    sweep() {}
+  },
+}));
+
+// Import AFTER the mocks are registered.
+// eslint-disable-next-line @typescript-eslint/no-require-imports
+import { McpService } from './mcp.service';
+
+type GateCreds = { email: string; password: string };
+
+// Build an McpService instance with stubbed constructor deps. We never call the
+// auth/db collaborators from the gate, so undefined stand-ins are fine for all
+// but moduleRef, which the MFA branch reads.
+function makeService(opts: {
+  checkMfaRequirements?: jest.Mock;
+}): { service: McpService; gate: (ws: unknown, creds: GateCreds) => Promise<void> } {
+  // Stub moduleRef.get -> returns an object whose checkMfaRequirements is the
+  // provided mock. The gate calls moduleRef.get(MfaModule.MfaService).
+  const moduleRef = {
+    get: jest.fn().mockReturnValue({
+      checkMfaRequirements:
+        opts.checkMfaRequirements ?? jest.fn().mockResolvedValue(undefined),
+    }),
+  };
+
+  const service = new McpService(
+    undefined as never, // environmentService
+    undefined as never, // workspaceRepo
+    undefined as never, // authService
+    undefined as never, // tokenService
+    undefined as never, // userRepo
+    undefined as never, // userSessionRepo
+    moduleRef as never, // moduleRef (read by the MFA branch)
+  );
+  // Stop the constructor's unref'd sweep timer leaking across tests.
+  service.onModuleDestroy();
+
+  // enforceBasicLoginGate is private; reach it through the instance. Calling the
+  // REAL method (not a stub) is the whole point of this suite.
+  const gate = (
+    service as unknown as {
+      enforceBasicLoginGate: (ws: unknown, creds: GateCreds) => Promise<void>;
+    }
+  ).enforceBasicLoginGate.bind(service);
+
+  return { service, gate };
+}
+
+const CREDS: GateCreds = { email: 'user@example.com', password: 'pw' };
+
+describe('McpService.enforceBasicLoginGate (REAL gate, leaf deps mocked)', () => {
+  beforeEach(() => {
+    // Reset to the community-build default (no EE module) before each test.
+    mfaModuleState = { bundled: false };
+    jest.clearAllMocks();
+  });
+
+  describe('SSO enforcement (validateSsoEnforcement)', () => {
+    it('rejects with Unauthorized when the workspace enforces SSO, before any MFA/login', async () => {
+      const { gate } = makeService({});
+      const workspace = { id: 'ws-1', enforceSso: true };
+
+      await expect(gate(workspace, CREDS)).rejects.toBeInstanceOf(
+        UnauthorizedException,
+      );
+      // The /mcp 401 surfaces an SSO-specific message (not a generic MCP error).
+      await expect(gate(workspace, CREDS)).rejects.toThrow(/enforced SSO/i);
+    });
+
+    it('does NOT consult the MFA module when SSO is enforced (gate short-circuits)', async () => {
+      // Even if the EE module WERE bundled, the SSO branch throws first, so the
+      // moduleRef MFA lookup must never run.
+      mfaModuleState = {
+        bundled: true,
+        checkMfaRequirements: jest.fn(),
+      };
+      const { service, gate } = makeService({
+        checkMfaRequirements: mfaModuleState.checkMfaRequirements,
+      });
+      const moduleRefGet = (
+        service as unknown as { moduleRef: { get: jest.Mock } }
+      ).moduleRef.get;
+
+      await expect(
+        gate({ id: 'ws-1', enforceSso: true }, CREDS),
+      ).rejects.toThrow(/enforced SSO/i);
+      // The SSO branch fired before the MFA require/lookup.
+      expect(moduleRefGet).not.toHaveBeenCalled();
+      expect(mfaModuleState.checkMfaRequirements).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('community build: EE MFA module NOT bundled', () => {
+    it('passes (no throw) when SSO is not enforced and the lazy require fails (no MFA gate)', async () => {
+      // mfaModuleState.bundled === false -> the virtual mock factory throws,
+      // exactly like require() of a missing EE module on a community build.
+      const { service, gate } = makeService({});
+      const moduleRefGet = (
+        service as unknown as { moduleRef: { get: jest.Mock } }
+      ).moduleRef.get;
+
+      await expect(
+        gate({ id: 'ws-1', enforceSso: false }, CREDS),
+      ).resolves.toBeUndefined();
+      // The require() failed, so the gate returned before touching moduleRef.
+      expect(moduleRefGet).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('EE MFA module bundled', () => {
+    it('rejects with a "use a Bearer token" signal when the user has MFA enabled', async () => {
+      const check = jest.fn().mockResolvedValue({
+        userHasMfa: true,
+        requiresMfaSetup: false,
+      });
+      mfaModuleState = { bundled: true, checkMfaRequirements: check };
+      const { gate } = makeService({ checkMfaRequirements: check });
+
+      const promise = gate({ id: 'ws-1', enforceSso: false }, CREDS);
+      await expect(promise).rejects.toBeInstanceOf(UnauthorizedException);
+      await expect(
+        gate({ id: 'ws-1', enforceSso: false }, CREDS),
+      ).rejects.toThrow(/Bearer access token/i);
+      // The real requirement check was consulted with the creds + workspace.
+      expect(check).toHaveBeenCalledWith(
+        CREDS,
+        { id: 'ws-1', enforceSso: false },
+        undefined,
+      );
+    });
+
+    it('rejects when the workspace enforces MFA (requiresMfaSetup)', async () => {
+      // requiresMfaSetup === true models a workspace that enforces MFA for a
+      // user who has not set it up yet; the Basic path cannot complete it.
+      const check = jest.fn().mockResolvedValue({
+        userHasMfa: false,
+        requiresMfaSetup: true,
+      });
+      mfaModuleState = { bundled: true, checkMfaRequirements: check };
+      const { gate } = makeService({ checkMfaRequirements: check });
+
+      await expect(
+        gate({ id: 'ws-1', enforceSso: false }, CREDS),
+      ).rejects.toThrow(/Bearer access token/i);
+    });
+
+    it('passes when the user has no MFA and the workspace does not enforce it', async () => {
+      const check = jest.fn().mockResolvedValue({
+        userHasMfa: false,
+        requiresMfaSetup: false,
+      });
+      mfaModuleState = { bundled: true, checkMfaRequirements: check };
+      const { gate } = makeService({ checkMfaRequirements: check });
+
+      await expect(
+        gate({ id: 'ws-1', enforceSso: false }, CREDS),
+      ).resolves.toBeUndefined();
+      // The bundled module's requirement check WAS consulted (proving we took
+      // the bundled branch, not the community no-op branch).
+      expect(check).toHaveBeenCalledTimes(1);
+    });
+
+    it('passes when checkMfaRequirements returns a falsy result (no requirement flags)', async () => {
+      // Defensive: a bundled module that returns undefined must not reject.
+      const check = jest.fn().mockResolvedValue(undefined);
+      mfaModuleState = { bundled: true, checkMfaRequirements: check };
+      const { gate } = makeService({ checkMfaRequirements: check });
+
+      await expect(
+        gate({ id: 'ws-1', enforceSso: false }, CREDS),
+      ).resolves.toBeUndefined();
+    });
+  });
+});

apps/server/src/integrations/mcp/mcp.service.spec.ts

@@ -264,6 +264,31 @@ describe('verifyBearerAccess (Bearer revocation/disabled checks)', () => {
       ),
     ).rejects.toThrow('jwt expired');
   });
+
+  // Item 3: bind the Bearer token to THIS instance's workspace (mirrors
+  // JwtStrategy). A token whose workspaceId claim differs from the instance
+  // workspace must be rejected; matching/absent expectedWorkspaceId is allowed.
+  it('rejects a token from a DIFFERENT workspace when expectedWorkspaceId is set', async () => {
+    await expect(
+      verifyBearerAccess('t', {
+        ...bearerDeps(),
+        expectedWorkspaceId: 'ws-OTHER',
+      }),
+    ).rejects.toThrow(UnauthorizedException);
+  });
+
+  it('accepts a token whose workspace matches expectedWorkspaceId', async () => {
+    const res = await verifyBearerAccess('t', {
+      ...bearerDeps(),
+      expectedWorkspaceId: 'ws-1',
+    });
+    expect(res).toEqual({ sub: 'user-1', email: 'u@e.com' });
+  });
+
+  it('does NOT enforce a workspace when expectedWorkspaceId is undefined (single-workspace no-op)', async () => {
+    const res = await verifyBearerAccess('t', bearerDeps());
+    expect(res).toEqual({ sub: 'user-1', email: 'u@e.com' });
+  });
 });
 
 describe('resolveMcpSessionConfig', () => {
@@ -587,23 +612,48 @@ describe('resolveMcpSessionConfig', () => {
   });
 });
 
-describe('isInitializeRequestBody (session-INIT detection)', () => {
+// A full, valid JSON-RPC InitializeRequest as the @modelcontextprotocol/sdk
-  it('true only for a single JSON-RPC object with method === "initialize"', () => {
+// `isInitializeRequest` predicate (which isInitializeRequestBody now delegates
-    expect(isInitializeRequestBody({ jsonrpc: '2.0', method: 'initialize' })).toBe(
+// to) requires: jsonrpc + id + method === 'initialize' + params.protocolVersion.
-      true,
+const fullInitializeRequest = {
-    );
+  jsonrpc: '2.0',
+  id: 1,
+  method: 'initialize',
+  params: {
+    protocolVersion: '2024-11-05',
+    capabilities: {},
+    clientInfo: { name: 'test-client', version: '1.0.0' },
+  },
+};
+
+describe('isInitializeRequestBody (session-INIT detection, matches SDK predicate)', () => {
+  it('true for a FULL valid InitializeRequest (the SDK predicate signal)', () => {
+    expect(isInitializeRequestBody(fullInitializeRequest)).toBe(true);
+  });
+
+  it('false for a bare { method: "initialize" } with no id/params (item 1)', () => {
+    // Item 1: this previously returned true (method-only check) and let an
+    // authenticated client POST a params-less body with no mcp-session-id, which
+    // ran the side-effecting login() before http.ts 400'd it. The SDK predicate
+    // rejects it (no id, no params.protocolVersion), so it no longer mints a
+    // session / audit row.
+    expect(isInitializeRequestBody({ method: 'initialize' })).toBe(false);
+    expect(
+      isInitializeRequestBody({ jsonrpc: '2.0', method: 'initialize' }),
+    ).toBe(false);
+    expect(
+      isInitializeRequestBody({ jsonrpc: '2.0', id: 1, method: 'initialize', params: {} }),
+    ).toBe(false);
   });
 
   it('false for a non-initialize method (e.g. tools/call)', () => {
     expect(
-      isInitializeRequestBody({ jsonrpc: '2.0', method: 'tools/call' }),
+      isInitializeRequestBody({ ...fullInitializeRequest, method: 'tools/call' }),
     ).toBe(false);
   });
 
   it('false for a batch (array) body, null/undefined, or a non-object', () => {
-    expect(
+    expect(isInitializeRequestBody([fullInitializeRequest])).toBe(false);
-      isInitializeRequestBody([{ jsonrpc: '2.0', method: 'initialize' }]),
-    ).toBe(false);
     expect(isInitializeRequestBody(undefined)).toBe(false);
     expect(isInitializeRequestBody(null)).toBe(false);
     expect(isInitializeRequestBody('initialize')).toBe(false);
@@ -618,8 +668,14 @@ describe('isSessionInit decision (no mcp-session-id AND initialize body)', () =>
   const decide = (sessionId: string | undefined, body: unknown): boolean =>
     !sessionId && isInitializeRequestBody(body);
 
-  it('no header + initialize body -> init', () => {
+  it('no header + full initialize body -> init', () => {
-    expect(decide(undefined, { method: 'initialize' })).toBe(true);
+    expect(decide(undefined, fullInitializeRequest)).toBe(true);
+  });
+
+  it('no header + bare params-less initialize body -> NOT init (item 1)', () => {
+    // A header-less { method: 'initialize' } with no params is no longer treated
+    // as an init by the SDK predicate, so it does not mint a session via login().
+    expect(decide(undefined, { method: 'initialize' })).toBe(false);
   });
 
   it('no header + non-initialize body -> NOT init (verifyCredentials path)', () => {
@@ -627,7 +683,7 @@ describe('isSessionInit decision (no mcp-session-id AND initialize body)', () =>
   });
 
   it('has session-id -> never init regardless of body', () => {
-    expect(decide('sess-1', { method: 'initialize' })).toBe(false);
+    expect(decide('sess-1', fullInitializeRequest)).toBe(false);
   });
 });
 

apps/server/src/integrations/mcp/mcp.service.ts

@@ -154,6 +154,15 @@ export class McpService implements OnModuleDestroy {
   private async verifyMcpBearer(
     token: string,
   ): Promise<{ sub?: string; email?: string }> {
+    // Resolve THIS instance's workspace so verifyBearerAccess can bind the
+    // token's `workspaceId` claim to it (mirrors JwtStrategy). The community
+    // build is single-workspace (findFirst), so this is the default workspace
+    // and the check is a no-op here; it only rejects a foreign-workspace token
+    // in a multi-workspace deployment. Undefined (no workspace configured) means
+    // no check — the credentials path would already have failed with no
+    // workspace, and an undefined here keeps the helper a no-op rather than
+    // rejecting every token.
+    const instanceWorkspace = await this.workspaceRepo.findFirst();
     // The revocation/disabled decision logic lives in the framework-free
     // verifyBearerAccess helper (unit-testable without the heavy auth graph);
     // this method only wires in the concrete TokenService + repos.
@@ -163,6 +172,7 @@ export class McpService implements OnModuleDestroy {
       verifyJwt: bindAccessJwtVerifier(this.tokenService) as (
         t: string,
       ) => Promise<JwtPayload>,
+      expectedWorkspaceId: instanceWorkspace?.id,
       findUser: (sub, workspaceId) =>
         this.userRepo.findById(sub, workspaceId),
       findActiveSession: (sessionId) =>