anchor.diff:  # Writing Plugins
  +
  +This page shows you how to write your own Buildkite plugin, and how to validate the `plugin.yml` file which describes it against the plugin schema.
  +
  +{:toc}
  +
  +## Plugin tutorial
   
   In this tutorial we'll create a Buildkite plugin called "File Counter", which counts the number of files in the build directory once the command has finished, and creates a build annotation with the count.
   
  
positive.code: 
  <%= render 'plugins/tutorial_readme' %>
  
  ## Add the linter
  
  The [Buildkite Plugin Linter](https://github.com/buildkite-plugins/buildkite-plugin-linter) helps ensure your plugin is up-to-date, and has all the required files to be listed in the plugin directory.
  
  
negative.code: docker-compose run --rm tests
  ```
  
  ### Add a readme
  
  Next we'll add a `README.md` file to introduce the plugin to the world:
  
  