Fix MCP error wrapping for DRC payloads

src/tools/tool-response.ts

@@ -0,0 +1,30 @@
+export type McpTextResult = {
+  content: Array<{
+    type: "text";
+    text: string;
+  }>;
+  isError?: true;
+};
+
+function isKicadFailure(result: unknown): boolean {
+  return (
+    typeof result === "object" &&
+    result !== null &&
+    "success" in result &&
+    (result as { success?: unknown }).success === false
+  );
+}
+
+export function formatKicadResult(result: unknown): McpTextResult {
+  const text = JSON.stringify(result) ?? String(result);
+
+  return {
+    content: [
+      {
+        type: "text",
+        text,
+      },
+    ],
+    ...(isKicadFailure(result) ? { isError: true as const } : {}),
+  };
+}