Learning Log

Building Review Apps with Kamal and GitHub Actions When I was using Heroku at work, one feature stood out as a game-changer for our development workflow: Review Apps. They made pull request testing seamless—isolated environments spun up automatically, inherited configuration from staging, and even provisioned separate add-ons like PostgreSQL and Redis. It transformed how we collaborated and tested changes. Fast forward to today. I’m running my Agentify app on a Hetzner server using Kamal for deployment. Everything is containerized with Docker—from local development with devcontainers and ngrok for tunneling, to production deployment on my Hetzner box. As I dove deeper into agentic coding, I found myself wishing for that same pull request workflow. I wanted to test changes in isolation, share environments with others, and validate features before merging. ...

When I started building Agentify, I took the straightforward path: hardcode the tool integrations directly into my Rails application. Need weather data? Write a method that calls the weather API. Need to search knowledge bases? Build it into the agent logic. It worked, but it wasn’t sustainable. Then the Model Context Protocol (MCP) standard emerged, promising a way to standardize tool interactions between AI agents and external services. Instead of building every integration myself, I could tap into a growing ecosystem of MCP servers. The question was: how do you actually implement this in a real Rails application? ...

What I Learned This Week 1. 12-Factor Agents This week I came across the 12-Factor Agents framework by HumanLayer, which adapts the well-known 12-Factor App principles for building robust and maintainable AI agents. Notable principle: Own Your Context Window Rather than sending the full conversation history with each agent interaction, this principle encourages summarizing or explicitly controlling the context that gets passed along. It’s a smart approach for performance and clarity — especially in longer or multi-agent flows. ...