fix(mcp-client): await Cordis startup discovery

packages/mcp/mcp-client/tests/apply.spec.ts

@@ -82,6 +82,7 @@ const stdioConfig: Config = {
   env: {},
   cwd: '',
   toolCallTimeoutMs: 60_000,
+  failOnStartupError: false,
 }
 
 // ---- Tests ----
@@ -150,11 +151,30 @@ describe('apply (plugin lifecycle)', () => {
     expect(ctx.tools.get('remote')).toBeUndefined()
   })
 
+  it('keeps the Cordis plugin loading until initial discovery publishes its tools', async () => {
+    const connection: PromiseWithResolvers<void> = Promise.withResolvers()
+    mockConnect.mockImplementation(async () => {
+      await connection.promise
+    })
+    const fiber = ctx.plugin({ name: 'mcp-client-lifecycle', inject, apply }, stdioConfig)
+    let activated = false
+    const activation = Promise.resolve(fiber).then(() => { activated = true })
+
+    await vi.waitFor(() => { expect(mockConnect).toHaveBeenCalled() })
+    expect(activated).toBe(false)
+    expect(ctx.tools.get('mcp__srv__remote')).toBeUndefined()
+
+    connection.resolve()
+    await activation
+    expect(ctx.tools.get('mcp__srv__remote')).toBeDefined()
+    await fiber.dispose()
+  })
+
   it('rejects a duplicate serverName at load and leaves the first instance intact', async () => {
     await apply(ctx, stdioConfig)
     expect(ctx.tools.get('mcp__srv__remote')).toBeDefined()
 
-    expect(() => { void apply(ctx, stdioConfig) }).toThrow(/serverName "srv" is already in use/)
+    await expect(apply(ctx, stdioConfig)).rejects.toThrow(/serverName "srv" is already in use/)
     // First instance unaffected.
     expect(ctx.tools.get('mcp__srv__remote')).toBeDefined()
   })
@@ -204,6 +224,19 @@ describe('apply (plugin lifecycle)', () => {
     expect(mockClose).toHaveBeenCalled()
   })
 
+  it('rejects activation and still closes the client when startup failure is configured as fatal', async () => {
+    mockConnect.mockRejectedValue(new Error('connection refused'))
+    await expect(apply(ctx, {
+      ...stdioConfig,
+      failOnStartupError: true,
+    })).rejects.toThrow('initial connection or tool discovery failed')
+
+    expect(mockListTools).not.toHaveBeenCalled()
+    expect(ctx.tools.get('mcp__srv__remote')).toBeUndefined()
+    await ctx.fiber.dispose()
+    expect(mockClose).toHaveBeenCalled()
+  })
+
   it('re-syncs tools on ToolListChanged notification', async () => {
     await apply(ctx, stdioConfig)
 
@@ -275,6 +308,7 @@ describe('apply (plugin lifecycle)', () => {
       url: 'http://localhost:3000/mcp',
       headers: { Authorization: 'Bearer x' },
       toolCallTimeoutMs: 30_000,
+      failOnStartupError: false,
     }
 
     await apply(ctx, httpConfig)

packages/mcp/mcp-client/tests/mcp-client.e2e.ts

@@ -75,6 +75,7 @@ describe('fixture server — controlled scenarios', () => {
     env: {},
     cwd: packageDir,
     toolCallTimeoutMs: 15_000,
+    failOnStartupError: false,
   }
 
   beforeAll(async () => {
@@ -164,10 +165,11 @@ describe('fixture server — duplicate serverName', () => {
       env: {},
       cwd: packageDir,
       toolCallTimeoutMs: 15_000,
+      failOnStartupError: false,
     }
     await apply(ctx, config)
 
-    expect(() => { void apply(ctx, config) }).toThrow(/serverName "dup" is already in use/)
+    await expect(apply(ctx, config)).rejects.toThrow(/serverName "dup" is already in use/)
 
     await ctx.fiber.dispose()
     await sleep(200)
@@ -185,6 +187,7 @@ describe('fixture server — disposal', () => {
       env: {},
       cwd: packageDir,
       toolCallTimeoutMs: 15_000,
+      failOnStartupError: false,
     })
 
     // Tools are registered before dispose.
@@ -210,6 +213,7 @@ describe('server-everything — official test server', () => {
     env: {},
     cwd: '',
     toolCallTimeoutMs: 30_000,
+    failOnStartupError: false,
   }
 
   beforeAll(async () => {
@@ -277,6 +281,7 @@ describe('server-filesystem — real filesystem operations', () => {
       env: {},
       cwd: '',
       toolCallTimeoutMs: 30_000,
+      failOnStartupError: false,
     }
     await apply(ctx, config)
   }, 60_000)
@@ -393,6 +398,7 @@ describe('streamable-http — in-process MCP server', () => {
       url: baseUrl,
       headers: { Authorization: 'Bearer e2e-test-token' },
       toolCallTimeoutMs: 15_000,
+      failOnStartupError: false,
     }
     await apply(ctx, config)
   }, 30_000)

packages/mcp/mcp-client/tests/mcp-client.spec.ts

@@ -713,6 +713,7 @@ describe('createTransport', () => {
       env: {},
       cwd: '/tmp',
       toolCallTimeoutMs: 60_000,
+      failOnStartupError: false,
     }
     const transport = createTransport(config)
     expect(transport).toBeDefined()
@@ -727,6 +728,7 @@ describe('createTransport', () => {
       url: 'http://localhost:3000/mcp',
       headers: {},
       toolCallTimeoutMs: 60_000,
+      failOnStartupError: false,
     }
     const transport = createTransport(config)
     expect(transport).toBeDefined()
@@ -741,6 +743,7 @@ describe('createTransport', () => {
       url: 'http://localhost:3000/mcp',
       headers: { Authorization: 'Bearer token' },
       toolCallTimeoutMs: 60_000,
+      failOnStartupError: false,
     }
     const transport = createTransport(config)
     expect(transport).toBeDefined()
@@ -764,6 +767,7 @@ describe('createTransport', () => {
         env: { EXTRA: 'injected' },
         cwd: '',
         toolCallTimeoutMs: 60_000,
+        failOnStartupError: false,
       }
       // createTransport internally calls buildChildEnv; we verify by inspecting
       // the constructed StdioClientTransport. Since we can't inspect private fields
@@ -791,6 +795,7 @@ describe('createTransport', () => {
       env: { CUSTOM: 'value' },
       cwd: '',
       toolCallTimeoutMs: 60_000,
+      failOnStartupError: false,
     }
     const transport = createTransport(config)
     expect(transport).toBeDefined()