Show HN: ActionPrompt – A Rails Plugin for Managing Your LLM Prompts

[evtothedev]

Hi Everyone! I've just extracted this from our code base.

As LLMs have become ubiquitous in web applications, I've noticed that prompts intended for Claude or GPT have become scattered throughout our codebase or buried within objects. Often, these prompts were built inline through string manipulation. My thinking was two-fold, 1) Let's come up with a simple pattern for organizing and rendering these prompts, and 2) Let's make them easy to review.

This draws heavy inspiration from ActionMailer::Preview.

[graypegg]

From the codebase you extracted this from, how are you sending these prompt strings onward? I feel like it would really benefit from being inspired by all of ActionMailer, not just ActionMailer:::Preview. Being able to just fire these off in a job would be useful. Even better if you could act on those as part of the job, so kind of like a little controller/agent thing?

    config.action_prompt.delivery_method = :chatgpt_api
    config.action_prompt.chatgpt_api_settings = {
      api_key: Rails.env[:OPENAI_API_KEY]
    }

    ...

    class ApplicationPrompt < ActionPrompt::Base
      before_action :set_user

      def set_user
        @user = current_user || AnonUser.new
      end
    end

    class SupportAgentPrompt < ApplicationPrompt
      def ask(question)
        @question = question.strip.downcase

        if result = prompt(question:)    # renders `views/prompts/support_agent/ask.text.erb`,
                                         # ideally handles recognizing JSON and stripping out whitespace in response
          broadcast_append_to @user,
                              target: :support_chat,
                              partial: 'support_chat/message',
                              locals: { message: result, from: SupportAgentUser.new }
        end
      end
    end

    ...

    SupportAgentPrompt.ask.prompt_later "What's the best menu item?"