How do I use AI to summarize long email threads
Paste the thread into an AI chat tool like ChatGPT or Claude and ask it to summarize the decisions made, open questions, and who owes what. For a hands-off approach, use a built-in feature — Gmail's Gemini side panel and Outlook's Copilot both summarize threads in place with one click, no copying required.
The copy-paste method works everywhere and costs nothing. Open the thread, select all the messages, paste into your AI tool of choice, and use a prompt that asks for structure rather than prose. Something like: "Summarize this email thread. List the decisions made, the open questions, and any action items with the person responsible." You'll get a scannable answer instead of a paragraph that still takes three minutes to read. Built-in tools are faster but require a paid plan. Gmail's Gemini panel appears in the sidebar on Google Workspace Business plans and summarizes the open thread without leaving your inbox. Microsoft 365 Copilot does the same in Outlook, and it can also draft a reply based on the thread context. If your company already pays for either suite, check whether the feature is enabled before paying for a separate tool. Watch out for two common problems. First, long threads with heavy quoting confuse the model — the same message appears five times in nested replies, and the AI may treat an old point as current. Trim the quoted tails before pasting, or ask specifically for "the most recent decision on each topic." Second, AI summaries drop nuance. If a client expressed hesitation in a polite way, the summary may report agreement. For threads where tone matters — negotiations, complaints, anything with legal weight — read the original messages yourself and use the summary only as a map. A practical habit: summarize at handoff points, not continuously. When you're pulled into a thread that's been running for two weeks, or when you return from vacation to 40 unread messages in one conversation, that's when a summary saves real time. Summarizing a four-message thread takes longer than reading it.