GPT-5 working horribly bad on Cursor

Support Bug Reports
1

Describe the Bug

I was trying to use Github Tool inside Cursor for use-cases like finding latest open PRs and summarizing them, or trying to understand what new features are getting developed (expecting it to check latest PRs/Issues) to understand. While Claude-4-Sonnet was able to quickly use tool, gather information and summarize the details. GPT-5 took forever, going into infinite loop, and requiring manual intervention to stop. Not to mention how slow it was.

Steps to Reproduce

Added Github MCP Tool > Choose GPT-5 Model > Ask query like “What are the new features getting developed in this repo”.

Cannot upload any screenshots/screenrecordings because I was on my company’s workstation trying all this.

Expected Behavior

Should use the tool, and be able to understand the response. While observed that for multiple queries (like ones shared above) it was going into infinte loop.

I observed that having 0 open PRs was never intercepted by GPT-5 and it kept trying to find open PRs.

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.4.2 (Universal)
VSCode Version: 1.99.3
Commit: 07aa3b4519da4feab4761c58da3eeedd253a1670
Date: 2025-08-06T19:23:39.081Z (1 day ago)
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.6.0

Does this stop you from using Cursor

No - Cursor works, but with this issue

2

Hey, thanks for the report. We’ll work on improving this model’s performance soon.

3

true i had auto mode fix problem in 1 try that gpt 5 took 10 mints and just made new problems

4

Yea it is basically unusable. Takes like 10-20x longer than any other model I have gotten when using Auto, and even with relatively simple requests it overthinks.

Update: GPT-5 is a lot slower, but it does produce better results.