AI at Work: September 2026

ChatGPT stops choosing your thinking level for you, Claude's Cowork joins ordinary chat, Copilot gets better at your inbox, and custom GPTs are on the way out.

A filter on the month's product news for people who use these tools at work. Every item links to the vendor's own announcement.

Changes that matter at work

ChatGPT no longer picks "thinking" for you on Plus and Pro. Since 14 September, Instant stays Instant; if a question needs careful reasoning, you choose a thinking level yourself. On Free and Go there's a Think button. (OpenAI release notes, choosing a model)
Custom GPTs are being retired. OpenAI announced on 11 September that it plans to retire custom GPTs across plans, with a migration path to plugins. Don't build anything new on one; a Project does the same job. (OpenAI release notes)
Claude Cowork is now just Claude. From 16 September, the things Cowork did (longer tasks across your files and tools) can be started from any Claude chat. (Claude release notes)
Copilot can tidy your Outlook inbox. Microsoft's September notes list Copilot actions to move, copy, categorise and delete messages and manage rules, each with a confirmation prompt. (Microsoft 365 Copilot release notes)

One feature worth trying

ChatGPT in Word. Since 17 September a ChatGPT add-in is available in Microsoft Word. If your organisation allows it, try it on a document you'd normally copy into a chat window, and check which account it signs you in with before you use it on anything confidential. (OpenAI release notes)

One you can ignore for now

New model names. GPT-6 variants, Claude Opus 5.5 and Fable 5.1 all arrived this month. For everyday drafting and summarising, the default in your tool is fine. Pick a model by the job, fast or careful, not by the newest name.

One privacy point

Temporary chats in ChatGPT can now use your memory. When you start one you now choose Personalised or Unpersonalised. For a sensitive one-off, choose Unpersonalised. Either way it isn't saved to history or used for training while it stays temporary, and OpenAI may keep a copy for up to 30 days for safety checks. (Temporary chat FAQ)

One workflow to test

Take a repetitive writing job, like weekly meeting notes, and time yourself doing it once by hand and once with your approved AI tool, including the time spent checking. The time-saved calculator helps you work out whether it's worth making a habit.

Academy lessons updated this month

Later the same day every lesson in the main course was re-checked against the vendors' own documentation; the corrections are listed in the course update log.

All course updates