Buildkite Agent Release

Buildkite Agent Release

When to Use This Skill

Use this skill when you need to:

• Prepare a release for Buildkite Agent.

Instructions

1. Ask user which release line this is

The repo has two active release lines:

• v4 — released from main. Currently pre-releases (e.g. 4.0.0-beta.15).
• v3 — released from the v3 branch (e.g. 3.136.4).

Ask the user to pick v4 or v3 before doing anything else. The chosen line determines the base branch for everything below: main for v4, v3 for v3.

2. Double check the current commit is up to date with the release branch

The current commit should be up to date with the latest origin/main (v4) or origin/v3 (v3).

3. Determine the new version number

Find the latest version for the chosen line. Don't use gh release view on its own — it returns the latest stable release, which hides v4 pre-releases:

gh release list --repo buildkite/agent --limit 20

Then ask the user to decide the new version:

• v4 (while in beta): usually the next beta, e.g. 4.0.0-beta.14 → 4.0.0-beta.15.
• v3: ask whether it's a minor or patch bump.

4. Update the agent version file

Edit the version/VERSION to update the value to the new version number. Use the bare semver (e.g. 3.136.4 or 4.0.0-beta.15), not a v-prefixed tag.

5. Preview the auto-generated release notes

Generate the same notes GitHub will publish at release time, so they can be reviewed in the PR description. Set target_commitish to the release branch (main for v4, v3 for v3):

mkdir -p tmp
gh api -X POST repos/buildkite/agent/releases/generate-notes \
  -f tag_name=v3.136.4 \
  -f target_commitish=v3 \
  --jq .body > tmp/release-notes.md

This is a read-only API call — it does not create a release or tag. GitHub auto-detects the previous release and applies the categorisation from .github/release.yml. The tmp/ directory is gitignored, so the file won't be committed.

GitHub's auto-detection compares against the previous stable release, which is wrong for v4 betas (it would diff against the latest v3.x). For v4, pass the previous tag explicitly:

gh api -X POST repos/buildkite/agent/releases/generate-notes \
  -f tag_name=v4.0.0-beta.15 \
  -f target_commitish=main \
  -f previous_tag_name=v4.0.0-beta.14 \
  --jq .body > tmp/release-notes.md

Inspect tmp/release-notes.md. If any PRs are mis-categorised (e.g. landed under 🏠 Internal because they had no labels), fix the labels on those PRs and re-run the command.

6. Create the release PR

• Create a new branch for the release (e.g. release/v3.136.4 or release/v4.0.0-beta.15), based on the release branch.
• Commit the version/VERSION change.
• Push the branch and open a PR using gh pr create against the release branch (--base main for v4, --base v3 for v3):
  • Title: release: v3.136.4 (matching the convention from previous release PRs).
  • Body: contents of tmp/release-notes.md from the previous step.
  • Label: release — required so the PR-labels workflow passes, and so the release PR itself is excluded from its own auto-generated notes (configured in .github/release.yml).
  • Example: gh pr create --base v3 --title "release: v3.136.4" --body-file tmp/release-notes.md --label release.

The PR body is for human review only; the actual release notes are regenerated by gh release create --generate-notes in .buildkite/steps/github-release.sh when the release pipeline runs, so they will reflect any label fixes made between PR creation and release.

7. Done

• No manual GitHub release editing is required, but the user may want to review the auto-generated notes after the release publishes.