feat(a2a): support custom ClientFactory in A2AAgent for authenticated requests

src/a2a/__tests__/a2a-agent.test.ts

@@ -190,6 +190,29 @@ describe('A2AAgent', () => {
       await agent.invoke('Hello')
       expect(mockGetAgentCard).toHaveBeenCalledOnce()
     })
+
+    it('uses custom clientFactory when provided', async () => {
+      const customSendMessageStream = vi.fn().mockReturnValue(mockStream(createMockTaskResponse()))
+      const customGetAgentCard = vi.fn().mockResolvedValue(mockAgentCard)
+      const customCreateFromUrl = vi.fn().mockResolvedValue({
+        sendMessageStream: customSendMessageStream,
+        getAgentCard: customGetAgentCard,
+      })
+      const customFactory = { createFromUrl: customCreateFromUrl }
+
+      const agent = new A2AAgent({
+        url: 'http://localhost:9000',
+        clientFactory: customFactory as never,
+      })
+
+      await agent.invoke('Hello')
+
+      expect(customCreateFromUrl).toHaveBeenCalledWith('http://localhost:9000', undefined)
+      expect(customGetAgentCard).toHaveBeenCalledOnce()
+      expect(customSendMessageStream).toHaveBeenCalledOnce()
+      // Default mock should not have been called
+      expect(mockSendMessageStream).not.toHaveBeenCalled()
+    })
   })
 
   describe('stream', () => {

src/a2a/a2a-agent.ts

@@ -8,7 +8,7 @@
  */
 
 import type { AgentCard, Part } from '@a2a-js/sdk'
-import type { Client as A2AClientSdk } from '@a2a-js/sdk/client'
+import type { Client as A2AClientSdk, ClientFactory as ClientFactoryType } from '@a2a-js/sdk/client'
 import { ClientFactory } from '@a2a-js/sdk/client'
 import type { InvokableAgent, InvokeArgs, InvokeOptions } from '../types/agent.js'
 import { AgentResult } from '../types/agent.js'
@@ -31,6 +31,8 @@ export interface A2AAgentConfig {
   name?: string
   /** Optional description. If not provided, populated from the agent card after connection. */
   description?: string
+  /** Optional custom A2A ClientFactory for authenticating requests (e.g. SigV4, bearer token). */
+  clientFactory?: ClientFactoryType
 }
 
 /**
@@ -170,7 +172,7 @@ export class A2AAgent implements InvokableAgent {
 
     logExperimentalWarning()
 
-    const factory = new ClientFactory()
+    const factory = this._config.clientFactory ?? new ClientFactory()
     const client = await factory.createFromUrl(this._config.url, this._config.agentCardPath)
     this._agentCard = await client.getAgentCard()
     if (this.name === undefined && this._agentCard?.name) {