github:actionlint

GitHub Actionlint Skill

Configures actionlint CI on any repository using reviewdog/action-actionlint. The workflow lints .github/workflows/ files on push and pull request, reporting errors inline on PRs via reviewdog.

Tools Used

• Bash: ls, cat — detect existing setup in .github/workflows/
• Read: Load reference docs at runtime — reference/workflow-template.md — for the workflow YAML template and configuration notes
• Write: Create the workflow file (fresh setup path)
• Edit: Patch the existing workflow file (reconfigure path)
• AskUserQuestion: Prompts for target branch, fail level, and mandatory pre-write confirmation
• mcp__git__git_add / mcp__git__git_commit: Stage and commit the generated workflow file

Workflow

Step 1: Detect Existing Setup

Run the following commands to inspect the current state of .github/workflows/:

ls .github/workflows/ 2>/dev/null
cat .github/workflows/actionlint.yml 2>/dev/null
cat .github/workflows/actionlint.yaml 2>/dev/null

Branch based on what is found:

• No actionlint workflow exists — proceed to Step 2 (fresh setup)
• Workflow file exists — show current configuration (action version, target branch, fail level, reporter). Ask via AskUserQuestion:
  • "Reconfigure (re-run setup questions)" — continue to Step 2; the existing file will be overwritten
  • "Exit — keep current setup" — stop here, no changes

Step 2: Ask Configuration Options

Detect the default branch by running:

git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed 's|refs/remotes/origin/||'

If detection fails, default to main.

Ask via AskUserQuestion with the following options. Show the detected branch and recommended defaults:

Target branch (default: detected branch):

• Use detected branch (e.g., main)
• Enter a different branch name

Fail level — the severity at which actionlint causes the check to fail:

• error (recommended) — only errors fail the check; warnings are reported but non-blocking
• warning — both errors and warnings fail the check

Store the choices for use in Steps 3 and 4.

Step 3: Show Summary and Confirm

Before writing any files, present a summary table via AskUserQuestion. Do NOT write any files before this confirmation.

File	Action	Key config
.github/workflows/actionlint.yml	Create	Branch: main; fail level: error; reporter: auto-detect (PR check / push check)

Populate the "Key config" column with the actual choices the user made. Ask: "Create this file?" with options:

• Proceed — write the file
• Cancel — abort gracefully, no files written

Step 4: Generate Workflow File

Read reference/workflow-template.md and locate the ## Workflow Template section. Then generate the workflow file:

.github/workflows/actionlint.yml:

Adapt the template as follows:

• Target branch: Replace main with the user's choice in both the push.branches and pull_request.branches arrays
• Fail level: Replace error with the user's choice in the fail_level input

Write the file using the Write tool. If .github/workflows/ does not exist, create it first with mkdir -p .github/workflows.

Step 5: Commit and Report

Stage the generated file:

mcp__git__git_add([".github/workflows/actionlint.yml"])

Propose a plain-English commit message (no conventional prefixes). Examples:

• "Add actionlint CI workflow to lint GitHub Actions"
• "Add actionlint workflow for GitHub Actions linting"

Confirm the message with the user via AskUserQuestion, then commit:

mcp__git__git_commit(message)

If mcp__git__git_commit fails, fall back to:

git add .github/workflows/actionlint.yml
git commit -m "Add actionlint CI workflow"

Present a final summary showing:

• Which file was created
• Target branch and fail level chosen
• How the reporter works (auto-detects PR vs push context)
• Next steps: "Push the branch and open a PR to activate the workflow. Actionlint will run automatically on any future changes to .github/workflows/."

---

Error Handling

Situation	Action
.github/workflows/ directory does not exist	Create it with mkdir -p .github/workflows before writing
Existing actionlint workflow found	Show current config, offer reconfigure or exit
Default branch detection fails	Fall back to main, mention it to the user
mcp__git__git_commit fails	Fall back to Bash(git add ... && git commit -m "...")
User cancels at confirmation step	Abort gracefully; no files written

Related Skills

• /github:setup — Verify prerequisites (gh CLI, authentication, MCP token)
• /github:feature — Create a branch, commit, push, and open a pull request

Reference Files

• reference/workflow-template.md — Complete workflow YAML template, configuration notes, and local usage instructions