A2AMock
++ Mock A2A (Agent-to-Agent) protocol server for testing multi-agent systems. Implements the + A2A JSON-RPC protocol with agent card discovery, message routing, task management, and SSE + streaming. +
+ +Quick Start
+import { A2AMock } from "@copilotkit/aimock";
+
+const a2a = new A2AMock();
+
+a2a.registerAgent({
+ name: "translator",
+ description: "Translates text between languages",
+ skills: [{ id: "translate", name: "Translate" }],
+});
+
+a2a.onMessage("translator", "translate", [{ text: "Translated text" }]);
+
+const url = await a2a.start();
+// Agent card at: ${url}/.well-known/agent-card.json
+// JSON-RPC at: ${url}/Mounted Mode
++ Mount A2AMock onto an LLMock server to share a single port with LLM mocking and other + services: +
+import { LLMock, A2AMock } from "@copilotkit/aimock";
+
+const llm = new LLMock({ port: 5555 });
+const a2a = new A2AMock();
+
+a2a.registerAgent({ name: "assistant" });
+a2a.onMessage("assistant", "hello", [{ text: "Hi!" }]);
+
+llm.mount("/a2a", a2a);
+await llm.start();
+// A2A available at http://127.0.0.1:5555/a2aSubpath Import
+A2AMock is also available via a dedicated subpath import for tree-shaking:
+import { A2AMock } from "@copilotkit/aimock/a2a";Agent Registration
+Register agents with skills and capabilities:
+a2a.registerAgent({
+ name: "researcher",
+ description: "Research assistant",
+ version: "1.0.0",
+ skills: [
+ { id: "search", name: "Web Search", tags: ["research"] },
+ { id: "summarize", name: "Summarize" },
+ ],
+ capabilities: { streaming: true },
+});Message Patterns
+Route messages to responses using string or RegExp patterns:
+// String substring match
+a2a.onMessage("agent", "hello", [{ text: "Hi there!" }]);
+
+// RegExp match
+a2a.onMessage("agent", /^translate\s+(.+)/i, [{ text: "Translation result" }]);
+
+// Task with artifacts
+a2a.onTask("agent", "compute", [
+ { parts: [{ text: "42" }], name: "result" },
+]);Streaming Tasks
+Simulate streaming responses with SSE events:
+a2a.onStreamingTask("agent", "long-task", [
+ { type: "status", state: "TASK_STATE_WORKING" },
+ { type: "artifact", parts: [{ text: "partial result" }], name: "output" },
+ { type: "artifact", parts: [{ text: "final result" }], lastChunk: true, name: "output" },
+], 50); // 50ms delay between eventsConfig File
+A2AMock can be configured via the aimock JSON config file:
+{
+ "a2a": {
+ "path": "/a2a",
+ "agents": [
+ {
+ "name": "assistant",
+ "description": "A helpful assistant",
+ "skills": [{ "id": "chat", "name": "Chat" }],
+ "messages": [
+ { "pattern": "hello", "parts": [{ "text": "Hi there!" }] }
+ ]
+ }
+ ]
+ }
+}JSON-RPC Methods
+| Method | +Description | +
|---|---|
SendMessage |
+ Send a message, get a synchronous response | +
SendStreamingMessage |
+ Send a message, get an SSE stream of events | +
GetTask |
+ Retrieve a task by ID | +
ListTasks |
+ List tasks, optionally filtered by contextId | +
CancelTask |
+ Cancel a non-terminal task | +
Agent Card
+
+ The agent card is served at GET /.well-known/agent-card.json and includes all
+ registered agents' skills and capabilities. The A2A-Version: 1.0 header is
+ included on all responses.
+
Inspection
+a2a.health(); // { status: "ok", agents: 2, tasks: 5 }
+a2a.reset(); // Clears all agents and tasks