Python SDK v0.14.1

Removed

• Breaking: MCPServer.run_http() is gone (AGNT5-1569). It answered single JSON-RPC POSTs only (no GET stream, sessions or SSE), so it wasn't a compliant Streamable HTTP server. Publish tools with add_function, add_workflow or add_agent and AGNT5 serves them over Streamable HTTP at /mcp/{project}/{env}/{server}; use run_stdio() to serve a server locally.

Added

• ctx.caller on function and workflow contexts (AGNT5-1569): who called the run through a hosted MCP server, as a frozen Caller with server, tool, subject (an AGNT5 user id for OAuth, service_key:{id} for an API key), auth_method (oauth or api_key) and client (the OAuth client id or the client's User-Agent). It is None when the run wasn't started by an MCP tool call. It reads the trigger_type=mcp and mcp.* keys the runtime stamps on the run; no token reaches the run.

Fixed

• MCPServer.run_stdio() follows JSON-RPC 2.0 and MCP (AGNT5-1569). It no longer replies to notifications (any message without an id, such as notifications/initialized) or to responses from the client. An unknown method is -32601; an unknown tool or prompt, params or arguments that aren't an object, or a missing tool name is -32602; an unknown resource is -32002; a message without "jsonrpc": "2.0", a method or a string/integer id is -32600; a line that isn't JSON is -32700 instead of stopping the server. All of these were -32603, and a request without jsonrpc was served. A tool that raises now returns a result with isError: true and the error text, as hosted servers do, so the model can read it; it was a -32603 protocol error. ping returns {}. dispatch() returns None for messages that get no reply, and MCPServerError takes a JSON-RPC code.