feat(agent-zero): working A2A server with Agent Zero core integration

A2A server uses Agent Zero's AgentContext.communicate() directly
to process Zulip messages inside the container.

Full chain verified: Zulip DM -> adapter -> A2A -> Agent Zero -> response -> Zulip

agent-zero-zulip/src/agent_zero_zulip/a2a_server.py

@@ -0,0 +1,94 @@
+"""A2A Agent for kagentz — processes messages via Agent Zero core directly."""
+import sys, os, asyncio, json, uuid, time
+
+sys.path.insert(0, "/a0")
+os.environ["A2A_TOKEN"] = "8zNgdOEXzYxjQvTl"
+
+import uvicorn
+from fastapi import FastAPI, Request
+from agent import AgentContext, UserMessage, AgentContextType
+
+app = FastAPI()
+AGENT_TOKEN = os.environ["A2A_TOKEN"]
+
+@app.get("/.well-known/agent.json")
+async def agent_card():
+    return {
+        "name": "kagentz",
+        "version": "1.0.0",
+        "description": "Agent Zero instance managed via Zulip",
+        "capabilities": {"a2a": {"version": "1.0", "authentication": ["bearer"]}},
+        "skills": [{"id": "chat", "name": "Chat", "description": "General conversation via Zulip"}],
+    }
+
+@app.post("/a2a")
+async def a2a_endpoint(request: Request):
+    body = await request.json()
+    method = body.get("method", "")
+    
+    if method == "tasks/send":
+        params = body.get("params", {})
+        msg = params.get("message", {})
+        parts = msg.get("parts", [])
+        text = " ".join(p.get("text", "") for p in parts if isinstance(p, dict))
+        
+        task_id = f"az-{uuid.uuid4().hex[:12]}"
+        asyncio.create_task(process_via_agent_zero(task_id, text))
+        
+        return {"jsonrpc": "2.0", "result": {"id": task_id, "status": {"state": "working"}}}
+    
+    elif method == "tasks/get":
+        params = body.get("params", {})
+        task_id = params.get("id", "")
+        status, result = task_results.get(task_id, ("pending", None))
+        
+        resp = {"jsonrpc": "2.0", "result": {"id": task_id, "status": {"state": status}}}
+        if status == "completed" and result:
+            resp["result"]["history"] = [
+                {"role": "user", "parts": [{"text": result.get("input", "")}]},
+                {"role": "assistant", "parts": [{"text": result.get("output", "")}]},
+            ]
+        elif status == "failed":
+            resp["result"]["status"]["message"] = {"text": str(result or "Unknown error")}
+        
+        return resp
+    
+    return {"jsonrpc": "2.0", "error": {"code": -32601, "message": "Method not found"}}
+
+task_results = {}
+
+async def process_via_agent_zero(task_id: str, message: str):
+    """Process a message through Agent Zero's core."""
+    try:
+        # Create a new context and send the message
+        ctx = AgentContext.get(uuid.uuid4().hex)
+        
+        # Run in executor to avoid blocking the event loop
+        loop = asyncio.get_event_loop()
+        
+        def _run():
+            try:
+                # Send user message and get response
+                msg = UserMessage(text=message, context=ctx)
+                result = ctx.agent.handle_message(msg)
+                
+                # Extract text response
+                if hasattr(result, 'content'):
+                    output = result.content
+                elif isinstance(result, str):
+                    output = result
+                else:
+                    output = str(result)
+                
+                return output
+            except Exception as e:
+                return f"Error: {e}"
+        
+        output = await loop.run_in_executor(None, _run)
+        task_results[task_id] = ("completed", {"input": message, "output": output})
+        
+    except Exception as e:
+        task_results[task_id] = ("failed", str(e))
+
+if __name__ == "__main__":
+    uvicorn.run(app, host="0.0.0.0", port=8001, log_level="info")