gh pr comment Command Reference

By Kaveh Alemi·Latchkey

Post a comment on a pull request straight from your pipeline.

gh pr comment adds a comment to a pull request. CI jobs use it to post plan summaries, test results, or deploy links back onto the PR.

What it does

gh pr comment posts a comment on a PR (by number, URL, or the current branch). With --edit-last it updates the most recent comment by the same actor instead of adding a new one, keeping the PR thread tidy across re-runs.

Common flags and usage

--body / --body-file: comment text inline or from a file
--edit-last: update the previous comment instead of adding a new one
--create-if-none: with --edit-last, create one if none exists
[number | url | branch]: target a specific PR

Example

shell

- name: Post plan summary
  env:
    GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
  run: |
    terraform show -no-color tfplan > plan.txt
    gh pr comment "${PR_NUMBER}" --body-file plan.txt --edit-last --create-if-none

In CI

Use --edit-last --create-if-none so repeated runs update a single comment rather than flooding the PR. --body-file is convenient for posting a rendered terraform plan or test report.

Using this in CI

Cloud CLIs behave differently on a runner than on your laptop. They assume no interactive terminal, no cached credentials, and no browser for device-code flows, so the same command that works locally can hang or fail on a runner.

Authenticate with a short-lived OIDC token rather than a long-lived static key. GitHub Actions can exchange id-token: write for cloud credentials with no stored secret.
Always pass the non-interactive flag. Most cloud CLIs will otherwise prompt and hang until the job times out.
Pin the CLI version. Cloud CLIs change output formats between minor releases, and any script parsing that output will break silently.
Set the output format explicitly (--output json) rather than relying on the default, which can differ by version and configuration profile.

Key takeaways

--body-file posts file contents like a rendered plan or test report.
--edit-last --create-if-none keeps one updating comment across re-runs.
Target any PR by number, URL, or current branch.

Frequently asked questions

gh pr comment Command Reference?