Action Prompt provides a dead simple way to way to organize and render prompts within a Rails App. This draws heavy inspiration from ActionMailer::Preview.

Install the gem with gem "action_prompt".

1. Create a template for a prompt. These go in your app/prompts folder. For example, you might create app/prompts/hello_world.text.erb and give it the following content:

   You are a helpful assistant who replies with, "<%= @message >"
   

2. Create a preview class. These live in test/prompts and they inherit from ActionPrompt::Preview. For example, you might create tests/prompts/hello_world_preview.rb and give it the following context:

   class HelloWorldPreview < ActionPrompt::Preview
    def example_prompt
      render "hello_world", locals: {message: "Hello, world!"}
    end
   end

3. Next, start up your rails server (rails s) and navigate to http://localhost:3000/action_prompt/previews. You'll see a list of your prompts that resembles the following:

   image goes here

   You can now preview your prompts.

1. Assume you've followed step one above, and you have a prompt located at app/prompts/hello_world.text.erb.

2. You can now render this anywhere in your codebase with the following:

   ActionPrompt::Renderer.new.render("hello_world", locals: {message: "Now we're cooking"})
   # You are a helpful assistant who replies with, "Now we're cooking"

The gem is available as open source under the terms of the MIT License.