Active Agent 0.2: Making Ruby & Rails the Best Choice For AI Development

Rails hasn’t had much tooling for AI… until now.

Active Agent is the AI framework built specifically for Ruby and Rails. And now, it’s LIVE. 

Introducing Active Agent 0.2, a production-ready release candidate so you can start building AI features or refactoring your Rails apps today. 👇

Why Does Rails Need Active Agent?

I’ve been a Rubyist for over 17 years and also spent a decade building AI products in Python (primarily in computer vision, as I spoke about at RailsConf 2021). 

Every time I worked in Python, I missed the developer experience of Ruby and Rails and would still use Rails as an API. 

I’m most comfortable and productive when working with Ruby and Rails. I love the speed, clarity, and joy of using a language built for developer happiness.  

And that’s why Ruby can be the best language for building AI-powered products (hot take, but stay with me).

Ruby is expressive, readable, and intuitive. What better language for composing prompts and designing AI agent interactions?

And if Rails continues to live up to its hype (as the most productive framework for going from zero to MVP), there’s no reason why it can’t be the best framework for AI, especially for the next generation of startups that want to build fast and lean. 

The problem has never been with the language or framework. It’s the lack of AI tooling (as I spoke about at RubyConf 2022).

So, I took what I learned from Python and created a framework that blends advanced AI concepts with the developer experience of Rails. 

And with that, I’d like to present Active Agent: an AI development framework that feels as seamless as the rest of the Rails experience.

With this 0.2 release, Active Agent is production-ready, so you can start adding AI features to (or refactoring) your Rails apps TODAY.

My mission with Active Agent is to create the open source tools we need for Rails and help us be competitive with Python’s agent package ecosystem and Next JS’s AI SDKs. 

I want to help Rails developers build AI products in a way that feels intuitive and fun (if this is your first time here, I’m tonsoffun).

About Active Agent 

With Active Agent, Rails developers can ship AI-powered features in less than 10 lines of code.

It’s an abstract controller like Action Mailer, but for AI agents, prompts, and actions—all through a Generation Provider interface similar to Active Job Queue Adapters. 

Active Agent makes AI development as simple for Rails devs as sending and receiving email.

With Active Agent, you can:

🕵️‍♂️ Define agents that take prompts and perform actions

🤖 Interact with AI services to generate text, images, speech-to-text, speech-to-speech, and text-to-speech

✨ Render generative UI with action prompts and view templates

⚙️ Scale with asynchronous jobs and streaming

By bringing MVC conventions to AI, we’re making it easy for developers who love Ruby and Rails to build the next generation of AI-powered products. No previous AI experience required.

Active Agent 0.2 (Production-Ready Release Candidate)

I pushed a “soft release” of my code at RubyConf in November and shared it with a few friends and colleagues to get feedback. Now, I have a production-ready release candidate. 

In addition to existing functionality, 0.2 introduces:

📝 Plain text for prompt and response templates 📄

🧰 JSON schema templates for tools 🛠️

👩‍💻 HTML for generative UI 📲

With Action Prompt, built on the Abstract Controller interface, templates can now be rendered through Action View, supporting multi-part prompts and generative responses.

Now, your AI agents can seamlessly call actions that return formatted content to users or send structured data back to the agent—for smarter, more dynamic AI interactions.

What’s Next? (Roadmap)

In the coming weeks and months, I’ll be working on: 

✨ Support for more AI generation providers (including Anthropic, Google, and Ollama, so you can run local models like Llama, DeepSeek, and more—COMING VERY SOON)

✨ Enhanced generation supporting vision and embedding

✨ RAG and Hotwire integrations with open source examples

✨ Expanding callbacks for ActiveRecord integrations with Solid Agent (demo coming soon)

Get Involved

Here’s how you can get involved with Active Agent…

✨ Try it out (and open issues or submit a PR)

✨ Join the Active Agent Discord (new)

✨ Partner with me to work on your AI project (10% off projects signed Feb-March)

📩 Email me at justin@activeagents.ai

🐙 Find me on Bluesky, X, LinkedIn, Github

Work With Me

I offer consulting and development services to help companies build AI features into their products, refactor their apps, and build AI-powered MVPs from scratch. 

With the “AI Starter Kit,” I’ll help build your first AI agent within 30 days (starting at $5K). Monthly development retainers are also available.

Right now, I’m offering 10% off projects for new clients onboarding in February or March 2025. See more on my Services page and reach out to discuss.

What Inspired Active Agent?

I recently had an experience where I was working on AI features for a company with a large Rails monolith, built and maintained by experienced Rails developers. 

But instead of integrating AI directly into their Rails app, they built a separate Next.js application around the monolith’s API.

Why? Because Rails didn’t have the AI tooling they needed. 

Rails has always been about developer productivity, but when it came to AI, Rails developers were forced to look elsewhere.

Next.js was a more convenient choice, with built-in AI SDKs and first-party support.

I built Active Agent to change that.

With Active Agent, my goal is to help Rails developers build AI-powered applications faster and more efficiently than with Python or Next.js. 

It’s time for Ruby and Rails to become a first-class choice for AI development.

Try Active Agent now or partner with me to build better AI products.