Build Your Own Coding Agent: 300 Lines of Code to AI Mastery

In the ever-evolving tech landscape of 2025, building your own coding agent has become a crucial skill for developers seeking a competitive edge. Geoffrey Huntley, former Tech Lead for Developer Productivity at Canva and current engineer at Sourcegraph, demonstrates how to build a basic coding agent in a hands-on workshop using just 300 lines of code. Leveraging LLM tokens and a simple loop, the agent interacts with tools like file readers and bash command executors to automate coding tasks. Huntley emphasizes selecting the right agentic LLM model (like Claude Sonnet) and efficient context window management to avoid performance bottlenecks. Mastering this skill transforms you from an AI consumer to a creator, positioning you for success in today's demanding tech world.