How to Enable Step Debug Logging in GitHub Actions

Setting the ACTIONS_STEP_DEBUG secret to true makes every step emit verbose debug lines you can re-run a job to capture.

Add a repository or organization secret (or variable) named ACTIONS_STEP_DEBUG set to true, then re-run the job. For runner internals, set ACTIONS_RUNNER_DEBUG too.

Steps

Open Settings to Secrets and variables to Actions.
Add ACTIONS_STEP_DEBUG with the value true.
Re-run the failed job to capture the verbose log.

Emit your own debug lines

.github/workflows/ci.yml

steps:
  - run: |
      echo "::debug::Resolved version is $VERSION"
      npm run build

Gotchas

::debug:: lines only appear when step debug logging is enabled.
Debug logs can leak internal values; remove the secret when finished.

Related guides

How to Group Log Output Into Collapsible Sections in GitHub ActionsFold noisy command output into collapsible groups in GitHub Actions logs using the ::group:: and ::endgroup::… How to Safely Use a Context Value in a run Step in GitHub ActionsAvoid script injection in GitHub Actions by passing untrusted context values like PR titles into a run step t…