diff --git a/src/cli/bds-mcp.ts b/src/cli/bds-mcp.ts
index b5ca864..1129e95 100644
--- a/src/cli/bds-mcp.ts
+++ b/src/cli/bds-mcp.ts
@@ -74,6 +74,19 @@ async function main(): Promise<void> {
   const templateEngine = new TemplateEngine(notifier);
   const metaEngine = new MetaEngine();
 
+  // 3b. Point every engine at the active project so queries/mutations
+  //     target the correct project instead of the hardcoded 'default'.
+  const dataDir = activeProject.dataPath
+    ?? path.join(userData, 'projects', activeProject.id);
+
+  postEngine.setProjectContext(activeProject.id, dataDir);
+  mediaEngine.setProjectContext(activeProject.id, dataDir, dataDir);
+  postMediaEngine.setProjectContext(activeProject.id);
+  tagEngine.setProjectContext(activeProject.id, dataDir);
+  scriptEngine.setProjectContext(activeProject.id, dataDir);
+  templateEngine.setProjectContext(activeProject.id, dataDir);
+  metaEngine.setProjectContext(activeProject.id, dataDir);
+
   // 4. Create the MCP server with an 8-hour proposal TTL (CLI sessions can
   //    last overnight).
   const mcpServer = new MCPServer(
diff --git a/tests/cli/bds-mcp-project-context.test.ts b/tests/cli/bds-mcp-project-context.test.ts
new file mode 100644
index 0000000..4db3ea6
--- /dev/null
+++ b/tests/cli/bds-mcp-project-context.test.ts
@@ -0,0 +1,208 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+
+/**
+ * Verifies that the MCP standalone CLI calls setProjectContext() on every
+ * engine after resolving the active project from the database.
+ */
+
+// ── Spies that each mock-engine instance populates ──────────────────────────
+
+let postEngineSetProjectContext: ReturnType<typeof vi.fn>;
+let mediaEngineSetProjectContext: ReturnType<typeof vi.fn>;
+let postMediaEngineSetProjectContext: ReturnType<typeof vi.fn>;
+let tagEngineSetProjectContext: ReturnType<typeof vi.fn>;
+let scriptEngineSetProjectContext: ReturnType<typeof vi.fn>;
+let templateEngineSetProjectContext: ReturnType<typeof vi.fn>;
+let metaEngineSetProjectContext: ReturnType<typeof vi.fn>;
+
+function resetSpies(): void {
+  postEngineSetProjectContext = vi.fn();
+  mediaEngineSetProjectContext = vi.fn();
+  postMediaEngineSetProjectContext = vi.fn();
+  tagEngineSetProjectContext = vi.fn();
+  scriptEngineSetProjectContext = vi.fn();
+  templateEngineSetProjectContext = vi.fn();
+  metaEngineSetProjectContext = vi.fn();
+}
+
+// ── Active project data ─────────────────────────────────────────────────────
+
+const ACTIVE_PROJECT_CUSTOM_PATH = {
+  id: 'my-blog',
+  name: 'My Blog',
+  slug: 'my-blog',
+  description: 'Test project',
+  dataPath: '/custom/data/path',
+  createdAt: new Date(),
+  updatedAt: new Date(),
+  isActive: true,
+};
+
+const ACTIVE_PROJECT_DEFAULT_PATH = {
+  id: 'internal-project',
+  name: 'Internal Project',
+  slug: 'internal-project',
+  description: null,
+  dataPath: null,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+  isActive: true,
+};
+
+// ── Chainable query mock ────────────────────────────────────────────────────
+
+let mockActiveProject: typeof ACTIVE_PROJECT_CUSTOM_PATH | typeof ACTIVE_PROJECT_DEFAULT_PATH = ACTIVE_PROJECT_CUSTOM_PATH;
+
+function makeMockLocalDb() {
+  return {
+    select: vi.fn().mockReturnValue({
+      from: vi.fn().mockReturnValue({
+        where: vi.fn().mockReturnValue({
+          get: vi.fn().mockResolvedValue(mockActiveProject),
+        }),
+      }),
+    }),
+  };
+}
+
+// ── Hoisted mocks ───────────────────────────────────────────────────────────
+
+vi.mock('../../src/cli/platform', () => ({
+  platformConfigPath: vi.fn(() => '/tmp/mock-userdata'),
+}));
+
+vi.mock('../../src/main/database/connection', () => {
+  const mockDb = {
+    initializeLocal: vi.fn().mockResolvedValue(undefined),
+    getLocal: vi.fn(() => makeMockLocalDb()),
+    close: vi.fn().mockResolvedValue(undefined),
+  };
+  return {
+    initDatabase: vi.fn(() => mockDb),
+    getDatabase: vi.fn(() => mockDb),
+    DatabaseConnection: vi.fn(),
+  };
+});
+
+vi.mock('../../src/main/database/schema', () => ({
+  projects: { isActive: 'isActive' },
+}));
+
+vi.mock('drizzle-orm', () => ({
+  eq: vi.fn((_col: unknown, _val: unknown) => 'isActive=true'),
+}));
+
+vi.mock('../../src/main/engine/CliNotifier', () => ({
+  DbNotifier: vi.fn().mockImplementation(function(this: Record<string, unknown>) { return this; }),
+}));
+
+vi.mock('../../src/main/engine/PostEngine', () => ({
+  PostEngine: vi.fn().mockImplementation(function(this: Record<string, unknown>) {
+    this.setProjectContext = (...args: unknown[]) => postEngineSetProjectContext(...args);
+    return this;
+  }),
+}));
+
+vi.mock('../../src/main/engine/MediaEngine', () => ({
+  MediaEngine: vi.fn().mockImplementation(function(this: Record<string, unknown>) {
+    this.setProjectContext = (...args: unknown[]) => mediaEngineSetProjectContext(...args);
+    return this;
+  }),
+}));
+
+vi.mock('../../src/main/engine/PostMediaEngine', () => ({
+  PostMediaEngine: vi.fn().mockImplementation(function(this: Record<string, unknown>) {
+    this.setProjectContext = (...args: unknown[]) => postMediaEngineSetProjectContext(...args);
+    return this;
+  }),
+}));
+
+vi.mock('../../src/main/engine/TagEngine', () => ({
+  TagEngine: vi.fn().mockImplementation(function(this: Record<string, unknown>) {
+    this.setProjectContext = (...args: unknown[]) => tagEngineSetProjectContext(...args);
+    return this;
+  }),
+}));
+
+vi.mock('../../src/main/engine/ScriptEngine', () => ({
+  ScriptEngine: vi.fn().mockImplementation(function(this: Record<string, unknown>) {
+    this.setProjectContext = (...args: unknown[]) => scriptEngineSetProjectContext(...args);
+    return this;
+  }),
+}));
+
+vi.mock('../../src/main/engine/TemplateEngine', () => ({
+  TemplateEngine: vi.fn().mockImplementation(function(this: Record<string, unknown>) {
+    this.setProjectContext = (...args: unknown[]) => templateEngineSetProjectContext(...args);
+    return this;
+  }),
+}));
+
+vi.mock('../../src/main/engine/MetaEngine', () => ({
+  MetaEngine: vi.fn().mockImplementation(function(this: Record<string, unknown>) {
+    this.setProjectContext = (...args: unknown[]) => metaEngineSetProjectContext(...args);
+    return this;
+  }),
+}));
+
+vi.mock('../../src/main/engine/MCPServer', () => ({
+  MCPServer: vi.fn().mockImplementation(function(this: Record<string, unknown>) {
+    this.startCli = vi.fn().mockResolvedValue(undefined);
+    this.cleanup = vi.fn().mockResolvedValue(undefined);
+    return this;
+  }),
+}));
+
+// ── Tests ───────────────────────────────────────────────────────────────────
+
+describe('bds-mcp project context initialisation', () => {
+  const originalExit = process.exit;
+
+  beforeEach(() => {
+    resetSpies();
+    // Prevent process.exit from actually killing the test runner
+    process.exit = vi.fn() as never;
+  });
+
+  afterEach(() => {
+    process.exit = originalExit;
+    vi.restoreAllMocks();
+    vi.resetModules();
+  });
+
+  it('calls setProjectContext on all engines with the active project (custom dataPath)', async () => {
+    mockActiveProject = ACTIVE_PROJECT_CUSTOM_PATH;
+
+    await import('../../src/cli/bds-mcp');
+    // Give main() a tick to complete
+    await new Promise((r) => setTimeout(r, 100));
+
+    const expectedProjectId = 'my-blog';
+    const expectedDataDir = '/custom/data/path';
+
+    expect(postEngineSetProjectContext).toHaveBeenCalledWith(expectedProjectId, expectedDataDir);
+    expect(mediaEngineSetProjectContext).toHaveBeenCalledWith(expectedProjectId, expectedDataDir, expectedDataDir);
+    expect(postMediaEngineSetProjectContext).toHaveBeenCalledWith(expectedProjectId);
+    expect(tagEngineSetProjectContext).toHaveBeenCalledWith(expectedProjectId, expectedDataDir);
+    expect(scriptEngineSetProjectContext).toHaveBeenCalledWith(expectedProjectId, expectedDataDir);
+    expect(templateEngineSetProjectContext).toHaveBeenCalledWith(expectedProjectId, expectedDataDir);
+    expect(metaEngineSetProjectContext).toHaveBeenCalledWith(expectedProjectId, expectedDataDir);
+  });
+
+  it('uses internal userData path when project has no custom dataPath', async () => {
+    mockActiveProject = ACTIVE_PROJECT_DEFAULT_PATH;
+
+    await import('../../src/cli/bds-mcp');
+    await new Promise((r) => setTimeout(r, 100));
+
+    const expectedDataDir = '/tmp/mock-userdata/projects/internal-project';
+
+    expect(postEngineSetProjectContext).toHaveBeenCalledWith('internal-project', expectedDataDir);
+    expect(mediaEngineSetProjectContext).toHaveBeenCalledWith('internal-project', expectedDataDir, expectedDataDir);
+    expect(postMediaEngineSetProjectContext).toHaveBeenCalledWith('internal-project');
+    expect(tagEngineSetProjectContext).toHaveBeenCalledWith('internal-project', expectedDataDir);
+    expect(scriptEngineSetProjectContext).toHaveBeenCalledWith('internal-project', expectedDataDir);
+    expect(templateEngineSetProjectContext).toHaveBeenCalledWith('internal-project', expectedDataDir);
+    expect(metaEngineSetProjectContext).toHaveBeenCalledWith('internal-project', expectedDataDir);
+  });
+});