fix responses endpoint memory

src/server/routes/proxy/chat.stream.test.ts

@@ -2032,6 +2032,87 @@ describe('chat proxy stream behavior', () => {
     expect(targetUrl).toContain('/v1/messages');
   });
 
+  it('does not stick generic /v1/responses traffic to /v1/messages after a fallback success', async () => {
+    selectChannelMock.mockReturnValue({
+      channel: { id: 11, routeId: 22 },
+      site: { name: 'generic-site', url: 'https://upstream.example.com', platform: 'new-api' },
+      account: { id: 33, username: 'demo-user' },
+      tokenName: 'default',
+      tokenValue: 'sk-demo',
+      actualModel: 'upstream-gpt',
+    });
+
+    fetchMock
+      .mockResolvedValueOnce(new Response(JSON.stringify({
+        error: { message: 'Gateway time-out', type: 'upstream_error' },
+      }), {
+        status: 504,
+        headers: { 'content-type': 'application/json' },
+      }))
+      .mockResolvedValueOnce(new Response(JSON.stringify({
+        error: { message: 'Bad gateway', type: 'upstream_error' },
+      }), {
+        status: 502,
+        headers: { 'content-type': 'application/json' },
+      }))
+      .mockResolvedValueOnce(new Response(JSON.stringify({
+        id: 'msg_fallback_1',
+        type: 'message',
+        model: 'upstream-gpt',
+        content: [{ type: 'text', text: 'ok via messages fallback' }],
+        stop_reason: 'end_turn',
+        usage: { input_tokens: 7, output_tokens: 3, total_tokens: 10 },
+      }), {
+        status: 200,
+        headers: { 'content-type': 'application/json' },
+      }))
+      .mockResolvedValueOnce(new Response(JSON.stringify({
+        id: 'resp_recovered_1',
+        object: 'response',
+        model: 'upstream-gpt',
+        status: 'completed',
+        output_text: 'ok via recovered responses',
+        usage: { input_tokens: 6, output_tokens: 2, total_tokens: 8 },
+      }), {
+        status: 200,
+        headers: { 'content-type': 'application/json' },
+      }));
+
+    const firstResponse = await app.inject({
+      method: 'POST',
+      url: '/v1/responses',
+      payload: {
+        model: 'gpt-5.4',
+        input: 'hello',
+      },
+    });
+
+    expect(firstResponse.statusCode).toBe(200);
+    expect(firstResponse.json().output_text).toContain('ok via messages fallback');
+
+    const secondResponse = await app.inject({
+      method: 'POST',
+      url: '/v1/responses',
+      payload: {
+        model: 'gpt-5.4',
+        input: 'hello again',
+      },
+    });
+
+    expect(secondResponse.statusCode).toBe(200);
+    expect(secondResponse.json().output_text).toContain('ok via recovered responses');
+    expect(fetchMock).toHaveBeenCalledTimes(4);
+
+    const [firstUrl] = fetchMock.mock.calls[0] as [string, any];
+    const [secondUrl] = fetchMock.mock.calls[1] as [string, any];
+    const [thirdUrl] = fetchMock.mock.calls[2] as [string, any];
+    const [fourthUrl] = fetchMock.mock.calls[3] as [string, any];
+    expect(firstUrl).toContain('/v1/responses');
+    expect(secondUrl).toContain('/v1/chat/completions');
+    expect(thirdUrl).toContain('/v1/messages');
+    expect(fourthUrl).toContain('/v1/responses');
+  });
+
   it('prefers native /v1/responses for claude-family /v1/responses requests that explicitly ask for encrypted reasoning', async () => {
     selectChannelMock.mockReturnValue({
       channel: { id: 11, routeId: 22 },

src/server/routes/proxy/upstreamEndpoint.test.ts

@@ -216,6 +216,48 @@ describe('resolveUpstreamEndpointCandidates', () => {
     expect(order).toEqual(['responses', 'chat', 'messages']);
   });
 
+  it('does not remember messages fallback success for generic /v1/responses requests', async () => {
+    recordUpstreamEndpointSuccess({
+      siteId: baseContext.site.id,
+      endpoint: 'messages',
+      downstreamFormat: 'responses',
+      modelName: 'gpt-5.3',
+    });
+
+    const order = await resolveUpstreamEndpointCandidates(
+      {
+        ...baseContext,
+        site: { ...baseContext.site, platform: 'new-api' },
+      },
+      'gpt-5.3',
+      'responses',
+    );
+
+    expect(order).toEqual(['responses', 'chat', 'messages']);
+  });
+
+  it('does not block generic /v1/responses endpoints on transient upstream errors', async () => {
+    recordUpstreamEndpointFailure({
+      siteId: baseContext.site.id,
+      endpoint: 'responses',
+      downstreamFormat: 'responses',
+      modelName: 'gpt-5.3',
+      status: 504,
+      errorText: '{"error":{"message":"Gateway time-out","type":"upstream_error"}}',
+    });
+
+    const order = await resolveUpstreamEndpointCandidates(
+      {
+        ...baseContext,
+        site: { ...baseContext.site, platform: 'new-api' },
+      },
+      'gpt-5.3',
+      'responses',
+    );
+
+    expect(order).toEqual(['responses', 'chat', 'messages']);
+  });
+
   it('learns a better endpoint from explicit upstream protocol errors', async () => {
     recordUpstreamEndpointFailure({
       siteId: baseContext.site.id,

src/server/routes/proxy/upstreamEndpoint.ts

@@ -714,15 +714,37 @@ function inferSuggestedEndpointFromError(errorText?: string | null): UpstreamEnd
 
 function shouldBlockEndpointByError(status: number, errorText?: string | null): boolean {
   if (isEndpointDispatchDeniedError(status, errorText)) return true;
-  if (isEndpointDowngradeError(status, errorText)) return true;
+  if (status === 404 || status === 405 || status === 415 || status === 501) return true;
+  if (isUnsupportedMediaTypeError(status, errorText)) return true;
+
   const text = (errorText || '').toLowerCase();
   return (
-    text.includes('unsupported legacy protocol')
+    text.includes('convert_request_failed')
+    || text.includes('endpoint_not_found')
+    || text.includes('unknown_endpoint')
+    || text.includes('unsupported_endpoint')
+    || text.includes('unsupported_path')
+    || text.includes('not_found_error')
+    || text.includes('unsupported legacy protocol')
     || text.includes('please use /v1/')
     || text.includes('does not allow /v1/')
+    || text.includes('unknown endpoint')
+    || text.includes('unsupported endpoint')
+    || text.includes('unsupported path')
+    || text.includes('unrecognized request url')
+    || text.includes('no route matched')
+    || text.includes('does not exist')
   );
 }
 
+function shouldRememberSuccessfulEndpoint(input: {
+  endpoint: UpstreamEndpoint;
+  downstreamFormat: EndpointPreference;
+}): boolean {
+  if (input.downstreamFormat !== 'responses') return true;
+  return input.endpoint === 'responses';
+}
+
 export function resetUpstreamEndpointRuntimeState(): void {
   endpointRuntimeStates.clear();
 }
@@ -739,6 +761,8 @@ export function recordUpstreamEndpointSuccess(input: {
     wantsNativeResponsesReasoning?: boolean;
   };
 }): void {
+  if (!shouldRememberSuccessfulEndpoint(input)) return;
+
   const nowMs = Date.now();
   const key = buildEndpointRuntimeStateKey({
     siteId: input.siteId,