A course in eight lessons

Loop engineering

Stop being the person who prompts the agent. Design the system that does it — and stay the engineer.

I don't prompt Claude anymore. I have loops running that prompt Claude and figuring out what to do. My job is to write loops. Boris Cherny, head of Claude Code at Anthropic, quoted in Loop Engineering

Built entirely on Addy Osmani's post Loop Engineering, read in full. Each lesson is short, ends with a feedback loop you answer yourself, and points back at a primary source.

Lessons

Anatomy of a loop

Six parts. The map everything else attaches to.

The state file

The cheapest piece, and the spine. Build it today.

Skills as written intent

SKILL.md, and why a boring description wins.

Maker and checker

Never let the model grade its own homework.

Worktrees

Isolation removes collisions, not the orchestration tax.

The heartbeat

Automations, and /loop versus /goal.

Connectors and reach

MCP, and the eight-step loop assembled.

Staying the engineer

Verification, comprehension debt, cognitive surrender.

Reference

REF

Glossary

Every term, used the same way in every lesson.

REF

Loop anatomy

The cycle diagram, pre-flight checklist, commands.

REF

Primitive map

Codex and Claude Code, side by side.

REF

SKILL.md card

Copyable skill and verifier sub-agent files.

The caveat that runs through all of it Osmani is not selling this. "Its still early, I'm skeptical and you absolutely have to be careful about token costs." Two people build the identical loop; one moves faster on work they understand, the other avoids understanding the work. The loop does not know the difference. You do.

I am your teacher. These lessons are the start, not the whole thing. Ask me anything that is unclear, and bring me your own repo when you are ready to build the first loop on it.

Course built 2026-08-19 from addyosmani.com/blog/loop-engineering.