runtime: MCP stdio client and per-process connection manager

2026-11-07 15:37:55 +08:00 · 2026-09-08 12:02:16 +08:00
parent dd70d02491
commit 7967095dbc
4 changed files with 569 additions and 0 deletions
@@ -0,0 +1,96 @@
+"""Minimal MCP stdio server used by the client tests (echo + sleep tools)."""
+
+from __future__ import annotations
+
+import json
+import sys
+
+
+def respond(request_id: int, result: object) -> None:
+    sys.stdout.write(json.dumps({"jsonrpc": "2.0", "id": request_id, "result": result}) + "\n")
+    sys.stdout.flush()
+
+
+def main() -> None:
+    for line in sys.stdin:
+        try:
+            payload = json.loads(line)
+        except json.JSONDecodeError:
+            continue
+        method = payload.get("method", "")
+        request_id = payload.get("id")
+        if request_id is None:
+            continue  # notification (notifications/initialized)
+        if method == "initialize":
+            respond(
+                int(request_id),
+                {
+                    "protocolVersion": "2025-06-18",
+                    "capabilities": {"tools": {}},
+                    "serverInfo": {"name": "fake-mcp", "version": "0.1.0"},
+                },
+            )
+        elif method == "tools/list":
+            respond(
+                int(request_id),
+                {
+                    "tools": [
+                        {
+                            "name": "echo",
+                            "description": "Echo the given text back.",
+                            "inputSchema": {
+                                "type": "object",
+                                "properties": {"text": {"type": "string"}},
+                                "required": ["text"],
+                            },
+                        },
+                        {
+                            "name": "fail",
+                            "description": "Always reports a tool error.",
+                            "inputSchema": {"type": "object", "properties": {}},
+                        },
+                        {
+                            "name": "slow",
+                            "description": "Sleeps past any client timeout.",
+                            "inputSchema": {"type": "object", "properties": {}},
+                        },
+                    ]
+                },
+            )
+        elif method == "tools/call":
+            name = (payload.get("params") or {}).get("name")
+            if name == "echo":
+                text = str((payload.get("params") or {}).get("arguments", {}).get("text", ""))
+                respond(
+                    int(request_id),
+                    {
+                        "content": [{"type": "text", "text": f"echo: {text}"}],
+                        "isError": False,
+                    },
+                )
+            elif name == "fail":
+                respond(
+                    int(request_id),
+                    {"content": [{"type": "text", "text": "boom"}], "isError": True},
+                )
+            else:
+                import time
+
+                time.sleep(5)
+                respond(int(request_id), {"content": [], "isError": False})
+        else:
+            sys.stdout.write(
+                json.dumps(
+                    {
+                        "jsonrpc": "2.0",
+                        "id": request_id,
+                        "error": {"code": -32601, "message": f"unknown method {method}"},
+                    }
+                )
+                + "\n"
+            )
+            sys.stdout.flush()
+
+
+if __name__ == "__main__":
+    main()