mergify-config

name	mergify-config
description	Use Mergify config commands to validate configuration files, simulate Mergify actions, and write Mergify configuration. ALWAYS use this skill when validating, writing, editing, or simulating Mergify config. Triggers on config validate, config simulate, mergify configuration, mergify.yml, .mergify.yml, merge queue config, workflow rules, conditions.

Mergify Configuration Management

Overview

The mergify config command group provides tools for validating Mergify configuration files against the official schema and simulating what Mergify would do on a specific pull request using a local configuration file.

Commands

mergify config validate                              # Validate the configuration file
mergify config simulate PULL_REQUEST_URL             # Simulate actions on a PR

Configuration File Detection

Mergify CLI auto-detects the configuration file from standard locations:

• .mergify.yml
• .mergify/config.yml
• .github/mergify.yml

Override with --config-file / -f:

mergify config -f path/to/config.yml validate

Validating Configuration (validate)

Validates the Mergify configuration file against the official JSON schema fetched from https://docs.mergify.com/mergify-configuration-schema.json.

# Validate auto-detected config file
mergify config validate

# Validate a specific file
mergify config -f .mergify.yml validate

Output:

• If valid: prints a success message and exits with code 0
• If invalid: prints the number of errors and each error's path and message, then exits with code 1

Use in CI:

- name: Validate Mergify config
  run: mergify config validate

Simulating Actions (simulate)

Simulates what Mergify would do on a specific pull request using the local configuration file. This lets you test configuration changes before committing them.

mergify config simulate https://github.com/owner/repo/pull/123

Required arguments:

• PULL_REQUEST_URL -- Full GitHub URL of the pull request to simulate against

Options:

• --token / -t (env: MERGIFY_TOKEN or GITHUB_TOKEN) -- Authentication token
• --api-url / -u (env: MERGIFY_API_URL) -- Mergify API URL (default: https://api.mergify.com)

Output: Shows a title and detailed Markdown summary of what actions Mergify would take on the PR with the local configuration.

Writing and Editing Configuration

When helping a user write, edit, or understand a Mergify configuration file, always fetch the relevant documentation pages first. Do not rely on memorized knowledge -- the configuration format, available actions, and conditions syntax evolve over time.

Documentation index

Fetch https://docs.mergify.com/llms.txt to get the full documentation index with all available pages and their descriptions.

Key reference pages

Fetch the pages relevant to the user's request before writing any configuration:

Topic	URL
File format and structure	https://docs.mergify.com/configuration/file-format
Conditions syntax and attributes	https://docs.mergify.com/configuration/conditions
Data types (duration, templates)	https://docs.mergify.com/configuration/data-types
Configuration sharing and reuse	https://docs.mergify.com/configuration/sharing
Workflow automation overview	https://docs.mergify.com/workflow
All available actions	https://docs.mergify.com/workflow/actions
Writing your first rule	https://docs.mergify.com/workflow/writing-your-first-rule
Merge queue rules	https://docs.mergify.com/merge-queue/rules
Merge queue setup	https://docs.mergify.com/merge-queue/setup
Queue priority rules	https://docs.mergify.com/merge-queue/priority
Merge protections	https://docs.mergify.com/merge-protections/setup
Custom protection rules	https://docs.mergify.com/merge-protections/custom-rules
Merge protection examples	https://docs.mergify.com/merge-protections/examples
Commands and restrictions	https://docs.mergify.com/commands
JSON Schema	https://docs.mergify.com/mergify-configuration-schema.json

For individual actions (assign, backport, close, comment, copy, dismiss_reviews, edit, github_actions, label, merge, queue, rebase, request_reviews, review, squash, update), fetch the specific action page at https://docs.mergify.com/workflow/actions/<action_name>.

Workflow

1. Read the user's existing config (if any) to understand current state
2. Fetch the relevant doc pages for the features the user needs
3. Write or update the configuration based on the documentation
4. Validate: run mergify config validate to check for errors
5. Simulate (optional): run mergify config simulate <PR_URL> against a real PR to verify the rules behave as expected

Common Patterns

Test config changes before pushing

# Edit your .mergify.yml locally, then:
mergify config validate
mergify config simulate https://github.com/myorg/myrepo/pull/42
# If both look good, commit and push

CI validation gate

jobs:
  validate-mergify:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Install mergify-cli
        run: pip install mergify-cli
      - name: Validate Mergify config
        run: mergify config validate