Ensure MCP loops output the right response format

In a tool loop, you can't set response_format because the model needs to
be able to think in plain English. But you still need the final response
to be in the desired format, so we add response_format only on the last
iteration.

dist/index.js

@@ -48678,6 +48678,9 @@ async function mcpInference(request, githubMcpClient) {
     const messages = [...request.messages];
     let iterationCount = 0;
     const maxIterations = 5; // Prevent infinite loops
+    // We want to use response_format (e.g. JSON) on the last iteration only, so the model can output
+    // the final result in the expected format without interfering with tool calls
+    let finalMessage = false;
     while (iterationCount < maxIterations) {
         iterationCount++;
         coreExports.info(`MCP inference iteration ${iterationCount}`);
@@ -48685,13 +48688,15 @@ async function mcpInference(request, githubMcpClient) {
             messages: messages,
             max_tokens: request.maxTokens,
             model: request.modelName,
-            tools: githubMcpClient.tools,
         };
-        // Add response format if specified (only on first iteration to avoid conflicts)
-        if (iterationCount === 1 && request.responseFormat) {
+        // Add response format if specified (only on final iteration to avoid conflicts with tool calls)
+        if (finalMessage && request.responseFormat) {
             // eslint-disable-next-line @typescript-eslint/no-explicit-any
             chatCompletionRequest.response_format = request.responseFormat;
         }
+        else {
+            chatCompletionRequest.tools = githubMcpClient.tools;
+        }
         try {
             const response = await client.chat.completions.create(chatCompletionRequest);
             if (!('choices' in response)) {
@@ -48708,7 +48713,22 @@ async function mcpInference(request, githubMcpClient) {
             });
             if (!toolCalls || toolCalls.length === 0) {
                 coreExports.info('No tool calls requested, ending GitHub MCP inference loop');
-                return modelResponse || null;
+                // If we have a response format set and we haven't explicitly run one final message iteration,
+                // do another loop with the response format set
+                if (request.responseFormat && !finalMessage) {
+                    coreExports.info('Making one more MCP loop with the requested response format...');
+                    // Add a user message requesting JSON format and try again
+                    messages.push({
+                        role: 'user',
+                        content: `Please provide your response in the exact ${request.responseFormat} format specified.`,
+                    });
+                    finalMessage = true;
+                    // Continue the loop to get a properly formatted response
+                    continue;
+                }
+                else {
+                    return modelResponse || null;
+                }
             }
             coreExports.info(`Model requested ${toolCalls.length} tool calls`);
             // Execute all tool calls via GitHub MCP