Draft a follow-up email after every Fathom call

Build me an agent workflow that drafts a personalized follow-up email in Gmail every time a Fathom sales call finishes recording. The trigger is a Fathom webhook firing when a recording completes.

When the webhook fires, the agent should:

1. Pull the recording's AI summary using Fathom Get Summary and the full transcript using Fathom Get Transcript. Use the recording id from the webhook payload.

2. Identify the primary external attendee on the call (anyone whose email is not on our own domain). Look them up in HubSpot using Search Contacts by their email address. If they exist, grab their first name, last name, company, and contact id.

3. If the contact was found, look for an open deal associated with them using HubSpot Search Deals. Pull the deal name, amount, stage, close date, and last activity date. If there is no open deal, skip the deal recap and continue.

4. Using the Fathom summary, transcript, and HubSpot context, write a personalized follow-up email that does four things: thanks the attendee for their time, recaps the two or three concrete things they said mattered most (pull these from the transcript, not generic phrases), restates the agreed next steps with owners and dates, and answers any open question they raised on the call. Keep it warm and concise, no more than a few short paragraphs. Sign off as the rep whose Fathom account recorded the call.

5. Save the result as a Gmail draft using Create a Draft. Address it to the external attendee. The subject line should reference the topic discussed on the call, for example "Following up on our conversation about <topic>". Do not auto-send. The rep reviews and sends it themselves.

Guardrails: never call Gmail Send a Draft. If there is no clear external attendee on the call (internal-only meeting), exit silently without creating a draft. If Fathom returns no summary or transcript yet, wait briefly and retry once before giving up. Surface any failures so the rep knows a draft was not created.