Implement MCP ping method

ldk-server-mcp/CLAUDE.md

@@ -35,7 +35,7 @@ src/
 - **Version**: `2025-11-25`
 - **Spec**: https://spec.modelcontextprotocol.io/
 - **Transport**: stdio (one JSON-RPC 2.0 message per line)
-- **Methods implemented**: `initialize`, `tools/list`, `tools/call`
+- **Methods implemented**: `initialize`, `tools/list`, `tools/call`, `ping`
 - **Notifications handled**: `notifications/initialized` (ignored, no response)
 
 ## Config

ldk-server-mcp/README.md

@@ -101,7 +101,7 @@ Streaming RPCs such as `subscribe_events` and non-RPC HTTP endpoints such as `me
 
 - **Protocol version**: `2025-11-25`
 - **Transport**: stdio (one JSON-RPC 2.0 message per line)
-- **Methods**: `initialize`, `tools/list`, `tools/call`
+- **Methods**: `initialize`, `tools/list`, `tools/call`, `ping`
 
 ## Testing
 

ldk-server-mcp/src/main.rs

@@ -124,6 +124,11 @@ async fn main() {
 				let resp = JsonRpcResponse::new(id, serde_json::json!({ "tools": tools }));
 				serde_json::to_string(&resp).unwrap()
 			},
+			"ping" => {
+				// Per the MCP spec, a ping must be answered with an empty result object.
+				let resp = JsonRpcResponse::new(id, serde_json::json!({}));
+				serde_json::to_string(&resp).unwrap()
+			},
 			"tools/call" => {
 				let params = request.params.unwrap_or(Value::Null);
 				match params.get("name").and_then(|v| v.as_str()) {

ldk-server-mcp/tests/integration.rs

@@ -185,6 +185,25 @@ fn test_tools_list() {
 	}
 }
 
+#[test]
+fn test_ping() {
+	let mut proc = McpProcess::spawn();
+
+	proc.send(&json!({
+		"jsonrpc": "2.0",
+		"id": 1,
+		"method": "ping"
+	}));
+
+	let resp = proc.recv();
+	assert_eq!(resp["jsonrpc"], "2.0");
+	assert_eq!(resp["id"], 1);
+	// Per the MCP spec, ping is answered with an empty result object.
+	assert!(resp["result"].is_object(), "Expected result object, got: {}", resp["result"]);
+	assert_eq!(resp["result"].as_object().unwrap().len(), 0, "Expected empty result object");
+	assert!(resp.get("error").is_none(), "Ping must not return an error");
+}
+
 #[test]
 fn test_tools_call_unknown_tool() {
 	let mut proc = McpProcess::spawn();