Heroku

12-Factor Agents: Patterns of reliable LLM applications — Dex Horthy, HumanLayer

Jul 3, 2025 · 17:06

Dex Horthy, founder of HumanLayer, presents the 12-Factor Agents framework for building reliable LLM-powered applications, arguing that production-grade agents are primarily deterministic software with targeted LLM steps rather than fully autonomous loops. He distills patterns: own prompts and context windows, treat tools as JSON and code, use small focused agents with three to ten steps, contact humans via tool calls. Horthy emphasizes context engineering—LLMs are pure functions—and shows how to compact errors, unify state, and add pause/resume via APIs. He shares a DevOps agent that became a bash script, and advocates for outer-loop agents. The framework, which gained 4,000 GitHub stars in two months, treats agents as stateless reducers that meet users on any channel, with engineers controlling the inner loop of token and control flow.

Building Agentic Applications w/ Heroku Managed Inference and Agents — Julián Duque & Anush Dsouza

Jun 27, 2025 · 52:35

In this workshop, Heroku Principal Developer Advocate Julián Duque and Product Manager Anush Dsouza introduce Heroku Managed Inference and Agents, a platform designed to make every software engineer an AI engineer by simplifying the attachment of agents and AI to applications. They demonstrate an opinionated, curated set of models (e.g., Claude 4) and an agentic control loop running on Heroku's trusted compute (Dynos) that provides first-party tools like code execution (Python, Node, Go, Ruby), Postgres schema inspection and querying, and document conversion, all streaming responses in real time. The workshop walks through provisioning inference via a single CLI command or add-on, using a Jupyter notebook to chain multiple tools (e.g., HTML-to-markdown then Python execution), and attaching custom MCP servers (like Brave Search) that spin up one-off Dynos and scale to zero. They also show how to expose MCPs remotely via a server-sent events endpoint for use with Cursor or other clients, emphasizing security (read-only database followers, bearer tokens) and future OAuth support. The episode concludes with a call to try the platform via a free trial team valid through the weekend.