Fix AI chat request format, add error handling

Author: stephencme

src/api.ts

@@ -1,15 +1,19 @@
+import { randomUUID } from "crypto";
+
 const BASE_URL = "https://buildwithfern.com/learn";
+const X_FERN_HOST = "buildwithfern.com";
 
 export async function postChat(message: string) {
   const response = await fetch(`${BASE_URL}/api/fern-docs/search/v2/chat`, {
     method: "POST",
     headers: {
       "content-type": "application/json",
+      "x-fern-host": X_FERN_HOST,
     },
     body: JSON.stringify({
-      messages: [{ role: "user", content: message }],
-      url: "https://buildwithfern.com/learn",
-      filters: [],
+      messages: [{ role: "user", parts: [{ type: "text", text: message }] }],
+      conversationId: randomUUID(),
+      url: BASE_URL,
     }),
   });
 

src/mcp.ts

@@ -25,10 +25,17 @@ export function registerMcpTools(server: McpServer) {
     "Ask Fern AI about anything related to Fern.",
     { message: z.string() },
     async ({ message }) => {
-      const result = await api.postChat(message);
-      return {
-        content: [{ type: "text", text: result }],
-      };
+      try {
+        const result = await api.postChat(message);
+        return {
+          content: [{ type: "text", text: result }],
+        };
+      } catch (error) {
+        return {
+          content: [{ type: "text", text: "[ERROR] " + error.message }],
+          isError: true,
+        };
+      }
     }
   );
 }