import sys
import json

def main():
    while True:
        line = sys.stdin.readline()
        if not line:
            break
        try:
            req = json.loads(line)
            method = req.get("method")
            req_id = req.get("id")
            
            if method == "tools/list":
                resp = {
                    "jsonrpc": "2.0",
                    "id": req_id,
                    "result": {
                        "tools": [
                            {"name": "echo", "description": "Echo input", "inputSchema": {"type": "object"}}
                        ]
                    }
                }
            elif method == "tools/call":
                name = req["params"].get("name")
                args = req["params"].get("arguments", {})
                if name == "echo":
                    resp = {
                        "jsonrpc": "2.0",
                        "id": req_id,
                        "result": {
                            "content": [{"type": "text", "text": f"ECHO: {args}"}]
                        }
                    }
                else:
                    resp = {"jsonrpc": "2.0", "id": req_id, "error": {"message": "Unknown tool"}}
            else:
                resp = {"jsonrpc": "2.0", "id": req_id, "error": {"message": "Unknown method"}}
            
            sys.stdout.write(json.dumps(resp) + "\n")
            sys.stdout.flush()
        except Exception as e:
            sys.stderr.write(f"Error: {e}\n")
            sys.stderr.flush()

if __name__ == "__main__":
    main()