How do I use AI to summarize long email threads
Paste the thread into an AI assistant like ChatGPT or Claude and ask it to summarize the decisions made, open questions, and who owes what. For Gmail and Outlook users, built-in AI features (Gemini in Gmail, Copilot in Outlook) can summarize a thread in one click without copying anything. Both approaches take under a minute and work best when you ask for a specific output format rather than a generic summary.
The single biggest mistake people make is asking for "a summary." That produces a paragraph that restates the thread without telling you anything actionable. Instead, ask for structure: "List the decisions that were made, the questions still open, and any commitments with names attached." You will get something you can actually act on in ninety seconds. If you are in Gmail, the Gemini side panel can summarize any open thread directly, and it respects your Workspace permissions so nothing leaves your account. Outlook's Copilot does the same thing with a "Summarize" button at the top of the thread. These built-in options are the safer default for anything containing client names, pricing, or internal details, because you are not pasting company data into a consumer chat window. For threads that span weeks and involve five or more people, the copy-paste approach into Claude or ChatGPT usually produces a better result, because you can give it context the email client does not have. Tell it who you are in the thread and what you need to decide. Something like: "I am the vendor here. Summarize what the client has agreed to and what they are still stalling on." The framing changes the output substantially. One practical habit worth building: when you finish reading an AI summary of a long thread, paste that summary back into the thread as a reply titled "Recap and next steps." Everyone else on the chain gets the same clarity you just bought yourself, and it kills the follow-up emails asking what was decided. It takes ten extra seconds and it makes you look like the most organized person on the thread.