The Claude Code Field Guide

What’s inside

1. 1The onboarding fileOne doc the agent reads before it touches anything: what this is, where things live, what must never break.
2. 2Plans that outlive the chatThe plan lives in the repo as an index plus one small file per chapter, so any session can pick it up.
3. 3Agents with one jobSubagents with a narrow brief, skills for repeatable procedures, lanes for what each may change, and a limit on how many run at once.
4. 4Guardrails in code, not in the promptPropose-only tools, permission deny-lists, hooks that block, and guard scripts that fail the build.
5. 5Done means checkedGates that run before every commit, chained so a failure stops it, and the ways a green result can lie.
6. 6Models, money and limitsThe right model per job, measured; a ledger of every call; regeneration driven by inputs, never a clock.