fix(openai): avoid JSON mode for OpenAI endpoint; use plain text to prevent 400; maintain streaming SSE without Accept header

Author: hackall360

Libs/pollilib/index.js

@@ -283,7 +283,9 @@ export async function* chatStream(payload, client) {
     } catch {}
     const resp = await c.fetch(url, {
       method: 'POST',
-      headers: { 'Content-Type': 'application/json', 'Accept': 'text/event-stream' },
+      // Do not set Accept: text/event-stream — Pollinations returns SSE without it,
+      // and some gateways 500/400 if Accept is forced.
+      headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify(body),
       signal: controller.signal,
     });

src/main.js

@@ -1749,13 +1749,14 @@ async function handleChatResponse(initialResponse, model, endpoint) {
 
     if (Array.isArray(message.tool_calls) && message.tool_calls.length) {
       await handleToolCalls(message.tool_calls);
+      const wantJsonAgain = endpoint !== 'openai';
       response = await chat(
         {
           model: model.id,
           endpoint,
           messages: state.conversation,
           ...(shouldIncludeTools(model, endpoint) ? { tools: [IMAGE_TOOL], tool_choice: 'auto' } : {}),
-          response_format: { type: 'json_object' },
+          ...(wantJsonAgain ? { response_format: { type: 'json_object' } } : {}),
         },
         client,
       );
@@ -2265,13 +2266,14 @@ async function requestChatCompletion(model, endpoints) {
     let retriedNetwork = false;
     for (;;) {
       try {
+        const wantJson = endpoint !== 'openai';
         const response = await chat(
           {
             model: model.id,
             endpoint,
             messages: state.conversation,
             ...(shouldIncludeTools(model, endpoint) ? { tools: [IMAGE_TOOL], tool_choice: 'auto' } : {}),
-            response_format: { type: 'json_object' },
+            ...(wantJson ? { response_format: { type: 'json_object' } } : {}),
           },
           client,
         );