gh extension install: Add gh Extensions in CI

By Daniel Zoghalchali·Latchkey

gh extension install adds a gh CLI extension from a repository, extending gh with new subcommands.

Workflows that depend on a community gh extension install it as a setup step, ideally pinned to a release for reproducibility.

What it does

gh extension install adds an extension hosted in a GitHub repository, making its gh-prefixed commands available as gh subcommands. --pin locks the extension to a specific tag or commit so the version is reproducible.

Common usage

gh extension install owner/gh-myext
gh extension install owner/gh-myext --pin v1.4.0
gh extension list
gh extension install .

Flags

In CI

Set GH_TOKEN so installs from private extension repos authenticate. Always --pin a version in CI; tracking the default branch makes builds non-reproducible. Run gh extension list to confirm the install, and remember the extension binary must support the runner OS and architecture.

Common errors in CI

"there is already an installed extension that provides the X command" means it is installed; use --force or skip. "gh: To use GitHub CLI in a GitHub Actions workflow, set the GH_TOKEN environment variable" appears when a private extension repo needs auth. "X is not a gh extension" means the repo is missing a gh-X executable.

Using this in CI

CI checkouts are shallow and detached by default, which changes the answer this command gives you. Commands that read history, branch names, or tags need the checkout configured for it.

- uses: actions/checkout@v4
  with:
    fetch-depth: 0   # history, tags, and git describe all need this

- run: |
    git rev-parse --is-shallow-repository   # expect false
    git rev-parse --abbrev-ref HEAD          # prints HEAD when detached

Frequently asked questions

Related guides

References

• GitHub Actions documentation