Daily Vapi call coaching digest in Slack

Build me an agent workflow that runs every weekday at 8am in my local business time zone and posts a coaching-ready summary of yesterday's Vapi calls to a Slack channel.

Trigger: cron, Monday through Friday at 8:00am local time. When it fires, compute yesterday's business day window (start of yesterday to end of yesterday in the same local time zone) as ISO-8601 timestamps.

Step 1 — pull the calls. Use Vapi's List Calls action with createdAtGe set to the start of yesterday and createdAtLe set to the end of yesterday. Page through all results. If the list is empty, stop the workflow here without posting anything to Slack; zero-call days should be silent.

Step 2 — hydrate each call. For every call ID returned by List Calls, use Vapi's Get Call action to fetch the full detail: transcript, structured summary/analysis, duration, cost, outcome/endedReason, phone number, assistant name, and the recording URL if present.

Step 3 — aggregate the day. From the hydrated calls, compute: total calls; connected vs. voicemail split; average call duration; average cost per call and total spend; and an outcome breakdown covering qualified, not interested, callback requested, error/failed, and any other categories that show up. Then read across the transcripts and identify the top three recurring objections or questions the team heard. Finally, pick the two or three most review-worthy calls — either strong examples of good handling or clear coaching moments — and for each write one short sentence explaining why it made the list, plus the recording link.

Step 4 — post to Slack. Use Slack's Send a Message action to post to the channel the user configures (default: #call-coaching). Format the message so the headline numbers sit at the top (total calls, connected vs. voicemail, average duration, average cost, outcome breakdown), followed by the recurring objections section, followed by the two or three calls to review with their one-line reason and recording link. Use Slack mrkdwn (single asterisks for bold, angle-bracket links). Keep it scannable — a manager should be able to read it in under a minute.

Rules: never post an empty or near-empty digest. If the transcript analysis or coaching-pick logic fails for a specific call, degrade gracefully — still post the headline numbers and any sections that did work. Report the local business time zone, the channel, and the assistant filter (if any) as configurable inputs on the workflow.