Support MCP Python SDK v2 for in-process SDK MCP servers

[RonShub]

Summary

claude-agent-sdk==0.2.128 requires mcp>=1.23.0,<2.0.0, so an application that must run the now-stable mcp==2.0.0 server cannot install the Agent SDK in the same environment. Overriding the constraint is not a working workaround: the in-process bridge still targets MCP v1 low-level registration and dispatch APIs.

Minimal reproduction

from claude_agent_sdk import create_sdk_mcp_server, tool

@tool("echo", "Echo text", {"text": str})
async def echo(args):
    return {"content": [{"type": "text", "text": args["text"]}]}

create_sdk_mcp_server(name="demo", tools=[echo])

In a Python 3.13 environment with mcp==2.0.0 and claude-agent-sdk==0.2.128 installed with dependencies overridden, this fails with:

AttributeError: Server object has no attribute list_tools

The next incompatibility is in Query._handle_sdk_mcp_request, which accesses server.request_handlers; MCP v2 exposes constructor handlers and get_request_handler() instead.

Requested direction

Please migrate the in-process SDK MCP bridge to MCP v2 public APIs and then relax the upper bound. A supported solution could construct mcp.server.Server with on_list_tools / on_call_tool, and route through the v2 public handler or client/transport API instead of request_handlers.

This blocks applications that host a standards-current MCP v2 HTTP server and also use Agent SDK in-process tools in the same runtime. A compatibility timeline or recommended supported isolation pattern would also help.