fix: make echo work

Signed-off-by: Chojan Shang <chojan.shang@vesoft.com>

Author: Chojan Shang

README.md

@@ -36,47 +36,57 @@ Embed the agent inside another Python process without spawning your own pipes:
 
 ```python
 import asyncio
-import sys
-from pathlib import Path
-
-from acp import spawn_agent_process
-from acp.schema import InitializeRequest, NewSessionRequest, PromptRequest, TextContentBlock
-
-
-async def main() -> None:
-    agent_script = Path("examples/echo_agent.py")
-    async with spawn_agent_process(lambda _agent: YourClient(), sys.executable, str(agent_script)) as (conn, _proc):
-        await conn.initialize(InitializeRequest(protocolVersion=1))
-        session = await conn.newSession(NewSessionRequest(cwd=str(agent_script.parent), mcpServers=[]))
-        await conn.prompt(
-            PromptRequest(
-                sessionId=session.sessionId,
-                prompt=[TextContentBlock(type="text", text="Hello!")],
-            )
-        )
-
-
-asyncio.run(main())
-```
-
-`spawn_client_process` mirrors this pattern for the inverse direction.
-
-### Minimal agent sketch
-
-```python
-import asyncio
-
-from acp import Agent, AgentSideConnection, PromptRequest, PromptResponse, SessionNotification, stdio_streams
-from acp.schema import AgentMessageChunk, TextContentBlock
 
+from acp import (
+    Agent,
+    AgentSideConnection,
+    AuthenticateRequest,
+    AuthenticateResponse,
+    CancelNotification,
+    InitializeRequest,
+    InitializeResponse,
+    LoadSessionRequest,
+    LoadSessionResponse,
+    NewSessionRequest,
+    NewSessionResponse,
+    PromptRequest,
+    PromptResponse,
+    SetSessionModeRequest,
+    SetSessionModeResponse,
+    stdio_streams,
+    PROTOCOL_VERSION,
+)
+from acp.schema import (
+    AgentCapabilities,
+    AgentMessageChunk,
+    McpCapabilities,
+    PromptCapabilities,
+    SessionNotification,
+    TextContentBlock,
+)
 
 class EchoAgent(Agent):
     def __init__(self, conn):
         self._conn = conn
 
+    async def initialize(self, params: InitializeRequest) -> InitializeResponse:
+        mcp_caps: McpCapabilities = McpCapabilities(http=False, sse=False)
+        prompt_caps: PromptCapabilities = PromptCapabilities(audio=False, embeddedContext=False, image=False)
+        agent_caps: AgentCapabilities = AgentCapabilities(
+            loadSession=False,
+            mcpCapabilities=mcp_caps,
+            promptCapabilities=prompt_caps,
+        )
+        return InitializeResponse(
+            protocolVersion=PROTOCOL_VERSION,
+            agentCapabilities=agent_caps,
+        )
+    async def newSession(self, params: NewSessionRequest) -> NewSessionResponse:
+        return NewSessionResponse(sessionId="sess-1")
+
     async def prompt(self, params: PromptRequest) -> PromptResponse:
         for block in params.prompt:
-            text = getattr(block, "text", "")
+            text = block.get("text", "") if isinstance(block, dict) else getattr(block, "text", "")
             await self._conn.sessionUpdate(
                 SessionNotification(
                     sessionId=params.sessionId,

examples/echo_agent.py

@@ -3,24 +3,48 @@
 from acp import (
     Agent,
     AgentSideConnection,
+    AuthenticateRequest,
+    AuthenticateResponse,
+    CancelNotification,
     InitializeRequest,
     InitializeResponse,
+    LoadSessionRequest,
+    LoadSessionResponse,
     NewSessionRequest,
     NewSessionResponse,
     PromptRequest,
     PromptResponse,
-    SessionNotification,
+    SetSessionModeRequest,
+    SetSessionModeResponse,
     stdio_streams,
+    PROTOCOL_VERSION,
+)
+from acp.schema import (
+    AgentCapabilities,
+    AgentMessageChunk,
+    McpCapabilities,
+    PromptCapabilities,
+    SessionNotification,
+    TextContentBlock,
 )
-from acp.schema import TextContentBlock, AgentMessageChunk
 
 
 class EchoAgent(Agent):
     def __init__(self, conn):
         self._conn = conn
 
     async def initialize(self, params: InitializeRequest) -> InitializeResponse:
-        return InitializeResponse(protocolVersion=params.protocolVersion)
+        mcp_caps: McpCapabilities = McpCapabilities(http=False, sse=False)
+        prompt_caps: PromptCapabilities = PromptCapabilities(audio=False, embeddedContext=False, image=False)
+        agent_caps: AgentCapabilities = AgentCapabilities(
+            loadSession=False,
+            mcpCapabilities=mcp_caps,
+            promptCapabilities=prompt_caps,
+        )
+        return InitializeResponse(
+            protocolVersion=PROTOCOL_VERSION,
+            agentCapabilities=agent_caps,
+        )
 
     async def newSession(self, params: NewSessionRequest) -> NewSessionResponse:
         return NewSessionResponse(sessionId="sess-1")