What is the difference between ChatGPT agent mode and deep research?

The two tools answer different requests. Deep research is for "find out about this": it plans a search, reads widely, and hands back a report. Agent mode was for "go and do this": it used a browser like a person would, opening pages, clicking through results and filling in forms.

OpenAI launched deep research in February 2025 and agent mode in July 2025, and for a while agent mode could also run deep research with its visual browser. The help page for ChatGPT agent now opens with "ChatGPT agent is no longer available" and sends readers to ChatGPT Work for multi-step tasks and to the cloud browser for web tasks. Deep research still has its own entry in the tools menu.

Which one should I use for a literature search?

Deep research, when you want a quick survey of what is publicly available on a topic. It proposes a research plan you can edit, reads sources for 5 to 30 minutes, and cites each one. It cannot open paywalled papers you have not uploaded, so check every citation against the paper itself before it reaches your review.

The plan step is worth using. You can restrict the search to specific sites, add your own files, and correct the scope before it runs, which matters more than any prompt wording. Treat the report as a reading list with notes attached. A cited sentence tells you where to look, not what the paper established.

Is ChatGPT Work the same as agent mode?

It is the closest replacement. Work is the ChatGPT agent for longer tasks and finished deliverables such as reports, spreadsheets and presentations. It uses a cloud browser to carry out steps on websites, including ones you sign in to, and pauses for confirmation before acting. The cloud browser is available on paid plans other than Free and Go.

For research, Work suits tasks with a clear end product, such as collecting the submission rules of five journals into one table. For understanding a literature, the bottleneck is still reading the papers, and neither tool does that reading for you.