Iāve been digging into it today, and itās definitely a noticeable step forward from 5.4 in a few key areas.
GPT-5.5 is the strongest agentic coding model to date. On Terminal-Bench 2.0, which tests complex command-line workflows requiring planning, iteration, and tool coordination, it achieves a state-of-the-art accuracy of 82.7%.
Hereās what stood out straight away:
⢠Stronger reasoning and accuracy
It feels more reliable when working through complex tasks, especially anything that involves multiple steps or deeper thinking.
⢠Better at real-world work
Writing, research, analysing data, structuring ideas⦠it just handles these more smoothly without needing as much back-and-forth.
⢠Improved coding + technical help
If youāre building apps, automations, or workflows, the responses feel cleaner and more usable first time.
⢠More consistent outputs
Less randomness, fewer weird replies, and generally more predictable results when you give it a clear prompt.
⢠Handles larger context even better
Great if youāre working with long documents, big prompts, or ongoing projects.
What this actually means for us
For most people here, itās not about ānew featuresā⦠itās about getting better results faster.
⢠Fewer prompt tweaks
⢠More usable first drafts
⢠Better outputs for clients
⢠More reliable automations
If youāre using ChatGPT daily for business, content, or building tools⦠this should make things noticeably smoother.