"""Naive MCP server implementation that crashes on missing tools and lacks schema validation.

Also ignores the stateless 2026-07-28 specification: it has no input_required

flow, so tools that need client input cannot finish safely.

"""

from __future__ import annotations

from collections.abc import Callable

from typing import Any

class MCPServer:

def __init__(self) -> None:

self.tools: dict[str, Any] = {}

def register_tool(

self,

name: str,

description: str,

schema: dict[str, Any],

handler: Callable[[dict[str, Any]], str],

) -> None:

self.tools[name] = {

"name": name,

"description": description,

"inputSchema": schema,

"handler": handler,

}

def handle_request(self, request: Any) -> dict[str, Any]:

# Naive: does not check jsonrpc version or error handling

req_id = request.get("id")

method = request["method"]

if method == "tools/list":

tools_list = [

{

"name": t["name"],

"description": t["description"],

"inputSchema": t["inputSchema"],

}

for t in self.tools.values()

]

return {"jsonrpc": "2.0", "id": req_id, "result": {"tools": tools_list}}

if method == "tools/call":

params = request["params"]

tool_name = params["name"]

# Will crash if tool doesn't exist or handler raises

tool = self.tools[tool_name]

output = tool["handler"](params["arguments"])

return {

"jsonrpc": "2.0",

"id": req_id,

"result": {"content": [{"type": "text", "text": str(output)}]},

}

return {"jsonrpc": "2.0", "id": req_id, "error": {"code": -32601, "message": "Method not found"}}