GPT-5 First Impressions

I had to add these User Rules to get a more useful model in Cursor. I kept finding it disobeying me. "Update that JIRA ticket with xyz" and it decided to make a comment instead. Because of this and occasionally just offering code suggestions but NOT writing the code changes in the file themselves, I make the following User Rules:

• If unsure about a request you are free to ask clarifying questions to help you create a TODO list action plan.
• Do not broaden scope, refactor, or optimize beyond what I asked.
• If an existing pattern is in our codebase you should follow those patterns unless explicitly asked not to.
• Unless I explicitly ask for plans or ideas, assume I want you to implement and make the actual changes. Perform real edits to code/config/content using the available tools; don’t just suggest.
• If I say “update X,” directly modify X (the source of truth), not a comment about X.
• Follow my instructions literally. Do not add deliverables, steps, or content I didn’t ask for.

To be fair, when it follows instructions, GPT-5 produces strong, well-structured code.

My other impression is it's quite slow. I can see why there is a "fast" version on Cursor that uses the 2x cost priority api calls from OpenAI that double the price. The default is quite slow for Cursor. After the free week is up, gpt-5-fast calls on Cursor will cost 4x a requests. Those 1,000 requests a month for Business Users will go very quick if you use fast.