Ship a Lambda version and post release notes to Slack

When a new release is published in our GitHub repository, promote the matching AWS Lambda code to production and announce it in Slack.

Trigger on GitHub's release webhook, specifically the release-published event. When it fires, take the tag name from the webhook payload and call GitHub's Get Release by Tag to fetch the release name, tag, HTML URL, and the full release body.

In AWS Lambda, call Publish Version on the target function to snapshot the current $LATEST code and configuration as a new immutable version number. Then call Update Alias to move the production alias (for example, prod) onto that new version number so live traffic starts hitting the new code. The Lambda function name and the alias to roll should be inputs configured when the workflow is set up. Assume the code is already deployed to $LATEST by CI or another workflow — this workflow only cuts a version and moves the alias.

Read the raw release body and draft a friendly, non-technical release note aimed at engineering teammates who did not write the code: what changed at a high level, who it affects, and whether anything needs attention (breaking changes, migrations, action required). Keep it warm and short — three to six bullets, no jargon dumps, no copy-pasting the raw changelog verbatim. The tone-shaping is the whole reason this is an agent workflow rather than a fixed pipeline.

Post the summary to the engineering Slack channel using Slack Bot's Send a Message. Include the release name and tag, the new Lambda version number that was published, the alias that was rolled, and a link back to the GitHub release page for anyone who wants the full changelog.