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longhaul.cpp/tools/server/tests/fixtures/mcp_malformed_server.py
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2026-07-29 01:00:10 -05:00

114 lines
3.1 KiB
Python

#!/usr/bin/env python3
"""
MCP server that sends malformed responses and notifications during requests.
"""
import json
import sys
import os
def handle_initialize(params, req_id):
return {
"jsonrpc": "2.0",
"id": req_id,
"result": {
"protocolVersion": "2024-11-05",
"capabilities": {"tools": {}},
"serverInfo": {"name": "malformed-test", "version": "1.0"}
}
}
def handle_tools_list(params, req_id):
return {
"jsonrpc": "2.0",
"id": req_id,
"result": {
"tools": [
{
"name": "echo",
"description": "Echo back the input message",
"inputSchema": {
"type": "object",
"properties": {
"message": {"type": "string"}
}
}
}
]
}
}
def handle_tools_call(params, req_id):
tool_name = params.get("name")
arguments = params.get("arguments", {})
if tool_name == "echo":
message = arguments.get("message", "")
# Send a notification first (no id field)
notif = {
"jsonrpc": "2.0",
"method": "notifications/progress",
"params": {"progress": 50, "total": 100}
}
sys.stdout.write(json.dumps(notif) + "\n")
sys.stdout.flush()
# Then send the actual response
return {
"jsonrpc": "2.0",
"id": req_id,
"result": {
"content": [{"type": "text", "text": f"echo: {message}"}]
}
}
else:
return {
"jsonrpc": "2.0",
"id": req_id,
"error": {"code": -32602, "message": f"Unknown tool: {tool_name}"}
}
HANDLERS = {
"initialize": handle_initialize,
"tools/list": handle_tools_list,
"tools/call": handle_tools_call,
}
def main():
sys.stdout = os.fdopen(sys.stdout.fileno(), "w", buffering=1)
sys.stderr = os.fdopen(sys.stderr.fileno(), "w", buffering=1)
for line in sys.stdin:
line = line.strip()
if not line:
continue
try:
request = json.loads(line)
except json.JSONDecodeError:
# Send malformed JSON response
sys.stdout.write("THIS IS NOT JSON\n")
sys.stdout.flush()
continue
method = request.get("method")
req_id = request.get("id")
params = request.get("params", {})
# JSON-RPC 2.0: a message without an id is a notification and must not receive a response
if req_id is None:
continue
handler = HANDLERS.get(method)
if handler:
response = handler(params, req_id)
else:
response = {
"jsonrpc": "2.0",
"id": req_id,
"error": {"code": -32601, "message": f"Method not found: {method}"}
}
sys.stdout.write(json.dumps(response) + "\n")
sys.stdout.flush()
if __name__ == "__main__":
main()