15-conditional-logic.md

Make Your Workflow Smarter with Conditional Logic

A workflow that always runs is useful — a workflow that only runs when it matters is elegant.

🎯 What You'll Do

Add a conditional check to your daily-status workflow so it only posts a summary when there have been recent commits. You'll learn how to use shell commands to gather context, expose that context as step outputs, and wire it into an if: condition that short-circuits the agent job entirely on quiet days.

📋 Before You Start

• You have a working daily-status workflow from Build: Daily Repo Status Workflow.
• You understand how to edit and re-run a workflow from Test and Improve Your Workflow.

Steps

Understand the problem

Your daily-status workflow currently runs every weekday regardless of repository activity, which means it can produce empty or near-empty summaries like "No activity to report" on quiet days. Over time these hollow reports erode confidence in the tool because readers learn to ignore them. Conditional logic solves this by inspecting repository state in a deterministic shell step before any AI processing begins, then skipping the agent job entirely when the precondition is not met.

The approach breaks into three parts:

1. Run a shell command to count commits from the last 24 hours and write the result to $GITHUB_OUTPUT.
2. Reference that output using the steps context expression ${{ steps.recent.outputs.commit_count }}.
3. Add a top-level if: key in the workflow frontmatter that skips the agent job when the count evaluates to zero.

Add a commit-count step

Open your daily-status workflow file (e.g., .github/workflows/daily-status.md) and add the following block inside the YAML frontmatter under steps::

steps:
  - name: Count recent commits
    id: recent
    run: |
      COUNT=$(git log --oneline --since="24 hours ago" | wc -l | tr -d ' ')
      echo "commit_count=$COUNT" >> $GITHUB_OUTPUT

This shell command uses git log with a --since time filter to list only commits from the last 24 hours, pipes the output through wc -l to count the lines, strips surrounding whitespace with tr -d ' ', and writes the final integer to $GITHUB_OUTPUT — a special GitHub Actions file that shares values between steps using key=value notation. The id: recent field is essential: it creates a named slot in the steps context so the value can be referenced as steps.recent.outputs.commit_count in later steps or in the top-level if: condition.

Note

`$GITHUB_OUTPUT` makes step outputs available to later steps as `steps..outputs.key`.

For a deeper explanation of how the steps context works alongside other context objects (github, env, runner), how to use built-in expression functions like contains() and toJSON(), and how to chain conditions with && and ||, see Side Quest: GitHub Actions Expressions and Contexts.

Add a top-level condition in frontmatter

In the same frontmatter block, add a top-level if: key at the same indentation level as on: and steps::

if: steps.recent.outputs.commit_count != '0'

This condition is embedded into the generated lock file during compilation; at runtime, GitHub Actions evaluates it and skips the agent job entirely whenever commit_count evaluates to '0'. You can also reference the count inside your prompt text to give the model concrete context — for example: "Summarise the last ${{ steps.recent.outputs.commit_count }} commits" anchors the analysis to the actual number of changes rather than leaving the model to guess the scope.

Exercise: Add a weekend skip condition

Now that the commit-count condition is in place, extend the workflow to also skip execution on weekends. This exercise reinforces how to chain multiple conditions in a single if: expression.

1. Add a step that writes the current day name as an output:

- name: Check day of week
  id: day
  run: echo "day=$(date +%A)" >> $GITHUB_OUTPUT

1. Update the top-level if: to combine both conditions using &&:

if: steps.recent.outputs.commit_count != '0' && steps.day.outputs.day != 'Saturday' && steps.day.outputs.day != 'Sunday'

1. Compile the workflow with gh aw compile to regenerate the lock file with the combined condition.

2. Trigger a manual workflow_dispatch run from the Actions tab.

3. Inspect the run log: on a weekday with commits the agent job should complete normally; on a weekend or a day with no commits it should appear as skipped with a grey icon, as shown below.

Compile your changes

After editing the frontmatter, compile the workflow to confirm everything is valid:

gh aw compile

You should see ✅ Compiled successfully. This regenerates your .lock.yml file with the updated conditional logic embedded in the job definition.

Note

The if: condition is applied during compilation and will not take effect until you compile and push both the .md source and the updated .lock.yml file.

Commit and push your conditional logic

Terminal path

git add .github/workflows/daily-status.md .github/workflows/daily-status.lock.yml
git commit -m "feat: skip summary on days with no commits"
git push

🖥️ GitHub UI path

1. Navigate to .github/workflows/daily-status.md in your repository on GitHub.
2. Click the pencil icon (✏️) to open the editor.
3. Add the steps: block and if: field to the frontmatter.
4. Click Commit changes.

[!IMPORTANT] Committing the .md file via the web editor does not automatically recompile the lock file. After committing, open your Codespace or local terminal and run gh aw compile, then push the updated .lock.yml. The if: condition will not take effect until the compiled lock file is pushed.

✅ Checkpoint

• Your workflow has a count recent commits step with id: recent
• Your workflow frontmatter includes if: steps.recent.outputs.commit_count != '0'
• gh aw compile completed without errors and the updated .lock.yml is committed and pushed
• Both .github/workflows/daily-status.md and .github/workflows/daily-status.lock.yml are committed and pushed
• You triggered the workflow manually and confirmed the conditional behaviour in the run log
• The workflow still posts a summary on days with commits

Next: Connect a Live Data Source to Your Workflow