The Comment Action allows you to automatically add or update comments on pull requests based on validation results. This is useful for providing feedback, instructions, or information to PR authors and reviewers.

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Configuration

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body
string
required
The content of the comment to add to the PR
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create_new
boolean
default:true
Whether to create a new comment (true) or update an existing one (false)

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Basic Usage

on_failure:
  - comment:
      body: "Please fix the issues with your PR"

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Examples

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Simple Comment

Add a basic comment when validations fail: 
on_failure:
  - comment:
      body: "Your PR doesn't meet our requirements. Please fix the issues."

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Detailed Feedback with Template Variables

Provide detailed feedback using template variables: 
on_failure:
  - comment:
      body: |
        Hello @{{ pull_request.user.login }},
        
        Thank you for your PR! There are some issues that need to be addressed:
        
        {{ validation_summary }}
        
        Please fix these issues and update your PR.

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Updating Existing Comments

Update the bot’s previous comment instead of creating a new one: 
on_failure:
  - comment:
      body: |
        # PR Validation Results
        
        {{ validation_summary }}
        
        _Last updated: {{ current_date }}_
      create_new: false

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Conditional Success Messages

Provide positive feedback when validations pass: 
on_success:
  - comment:
      body: |
        ## All checks passed! ✅
        
        Thank you for following our contribution guidelines.
        A maintainer will review your PR soon.

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Template Variables

The Comment Action supports these template variables:
VariableDescription
{{ pull_request.user.login }}PR author’s username
{{ pull_request.title }}PR title
{{ pull_request.body }}PR description
{{ pull_request.number }}PR number
{{ repository.name }}Repository name
{{ repository.full_name }}Full repository name (owner/repo)
{{ validation_summary }}Summary of all validation results

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How It Works

1

Process Template

The action processes the comment body, replacing template variables with actual values
2

Check Settings

If create_new is false, it looks for a previous comment from the Rulesets bot
3

Update or Create

If an existing bot comment is found (and create_new is false), it updates that comment; otherwise, it creates a new comment

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Practical Use Cases

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Onboarding New Contributors

Provide guidance to first-time contributors: 
ruleset:
  - name: "First-time Contributor"
    when:
      - "pull_request.opened"
    if:
      - type: "author"
        match: "{{ first_time_contributor }}"
    on_success:
      - commentbody: |
            ## Welcome to our project! 👋
            
            Thank you for your first contribution!
            
            Here are some helpful resources:
            - [Contribution Guidelines](CONTRIBUTING.md)
            - [Code of Conduct](CODE_OF_CONDUCT.md)
            - [Development Setup](docs/development.md)
            
            A maintainer will review your PR soon.

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CI Failure Summary

Summarize CI failures to save time: 
ruleset:
  - name: "CI Failure Summary"
    when:
      - "check_suite.completed"
    if:
      - type: "check_suite"
        status: "failure"
    on_success:
      - comment:
          body: |
            ## CI Failures Summary
            
            The following CI checks have failed:
            
            {{ ci_failures }}
            
            Please check the CI logs for details.

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Labeling Explanation

Explain why certain labels were added: 
ruleset:
  - name: "Large PR"
    when:
      - "pull_request.opened"
      - "pull_request.synchronize"
    validate:
      - type: "size"
        files: 10
        total: 500
    on_failure:
      - label:
          add: ["large-pr"]
      - comment:
          body: |
            ## Large PR Detected
            
            This PR has been labeled as `large-pr` because it:
            {{ validation_summary }}
            
            Consider breaking it down into smaller, more focused PRs if possible.

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Best Practices

Use Markdown formatting to make comments readable and structured
Include actionable feedback that helps contributors fix issues
Use template variables to personalize comments
Set create_new: false to avoid cluttering PRs with multiple similar comments
Avoid making comments too verbose or adding them too frequently, as this can be perceived as noisy

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Limitations

  • Comments are always posted from the GitHub App’s account
  • Markdown formatting in comments is limited to what GitHub supports
  • Template variables are limited to those provided by Rulesets