You've Been Doing Harness Engineering All Along

Sun, 26 Apr 2026 00:00:00 +0000

If you used LLMs for coding before the coding agents (~prior to Claude Code release in Feb last year), and if you got annoyed with typing the same context into LLM chat boxes, you’d start saving it into per-project markdown files. Many of those who used LLMs heavily ended up doing this eventually.

Then we got Claude Code and other agents, and by mid-summer, this technique got formalized as the AGENTS.md file and its tool-specific equivalents like CLAUDE.md, .cursor/rules, and .github/copilot-instructions.md. A few of us have been doing this before it had a name. At a bigger scale, that’s what happened to me with “Harness Engineering.”

Software-Engineering on Alex Kim's blog

You've Been Doing Harness Engineering All Along