Use Outlook Copilot to Summarize Long Supplier Email Threads

What This Does

Copilot in Outlook reads a long email thread and gives you a 3-5 sentence summary of what was discussed, what decisions were made, and what action items remain, so you can catch up on a supplier escalation thread in 30 seconds instead of reading 25 emails.

Before You Start

• You have Outlook open (desktop app or web at outlook.com / outlook.office.com)
• Microsoft 365 with Copilot enabled (M365 Business Standard + Copilot or equivalent)
• An email thread you want to summarize is open

Steps

1. Open the email thread you want to summarize

Find a long supplier email thread in your inbox. a PO status chain, a shortage escalation, or a pricing discussion. Click on it to open the thread.

2. Find the Copilot summary

At the top of the email thread (above the first message), look for the Summary by Copilot box. In classic Outlook it appears as a Summarize option instead.

Click it to generate the summary, which appears at the top of the thread with numbered citations that jump to the source emails.

3. Read the generated summary

Copilot generates a brief summary covering:

• What the thread is about
• Key decisions or commitments made
• Any open action items or unanswered questions
• Who is responsible for what (if stated in the thread)

4. Use the sidebar for follow-up

After reading the summary, you can ask Copilot follow-up questions in the sidebar:

• "What did Supplier X agree to deliver and by when?"
• "What are the open action items in this thread?"
• "Draft a follow-up email asking for a status update on the agreed delivery date"

Real Example

Scenario: You've been out of the office for a day, and there's a 22-email thread about a shortage from your packaging supplier. You need to know the current status before your 2pm call.

What you do: Open the thread, click Summarize. Copilot returns: "Supplier confirmed a 3-week delay on PO #48291 due to a raw material shortage. Your team requested an expedited partial shipment; supplier agreed to ship 40% of the order by 3/28. Logistics is arranging a spot truck. Outstanding: supplier needs delivery address confirmation by EOD today."

What you get: 30-second catch-up vs. 15-20 minutes of reading, exactly the information you need before the call.

Tips

• Copilot summarization works best on threads with 5+ emails. For short threads, just read them.
• For threads where you need to document the agreed resolution for your records, ask: "Write a 2-sentence summary of the resolution reached in this thread" and paste it into your PO tracking notes.
• If Copilot isn't available in your Outlook, use ChatGPT instead: copy the key emails from the thread and paste them with "Summarize this supplier email thread. what was agreed and what actions are pending?"

Tool interfaces change, if the Copilot button has moved, look for similar AI/sparkle options in the thread header or the three-dot menu.