Abstract diagram of an LLM connected to tools, checkpoints, approval gates, and trace logs

Why Agentic Harness Engineering Matters More Than Prompt Engineering

The live demo repo for this series is 67ailab/harness-engineering. This first post is grounded in the current public repo state rather than a made-up architecture diagram. For this article, I did not add a new repo feature before publishing; the existing baseline already supports the core claim. At the time of writing, that baseline includes typed tools, checkpointed run state, resumable execution, an approval gate before writing artifacts, per-step traces, a planner/reviewer split, and optional local OpenAI-compatible model support. ...

April 30, 2026 · 67 AI Lab