principle-build-the-lever

Installation
SKILL.md

Build the Lever

When the work isn't trivial, build the tool that does it instead of doing it by hand.

A codemod, generator, or script does the work the same way every time and reruns for free. The tool is one artifact a reviewer can read and rerun to check the work. Hand-done changes can only be re-verified by redoing them. A deterministic script turns "trust me" into "run this".

Default to building the lever. Skip it only when the task is trivial, a couple of obvious edits you can see at a glance.

  • Do the first unit by hand to learn the recipe, then build the tool. Prove it by rerunning it on that unit and diffing against your hand-done version. Make the lever safe to rerun.
  • Codemod or script for edits, generator for repetitive files, a dump-to-sqlite query for analysis, a rerunnable check for verification.
  • A deterministic lever beats fan-out. If the tool can process every unit in one pass, run it yourself. Don't fan out delegates to hand-apply what a script can do.
  • When you fan work out to subagents, write the lever as a skill they all read: the recipe, the verification contract, and the do-not-touch fences in one artifact. Keep it outside the delegates' write scope so they can't quietly edit the contract.
  • Subagents may communicate with each other, but no agent may communicate with a person. Repeat that sentence verbatim in every child prompt. Keep external communication manual: prepare local draft text for the user instead of sending messages, comments, replies, email, or chat posts.
  • Applying this principle produces a file. If you cited it and there is no codemod, script, generator, or delegate skill in the diff, you didn't apply it.
  • When the work outlives the session, keep the lever in the worktree. Commit it only when the user or invoking workflow explicitly authorizes a commit. If $commit-guidelines is available, apply it; otherwise inspect the exact commit diff, preserve unrelated work, run repository checks, use the repository's commit-message convention, and never add AI attribution.

The bar is triviality, not repetition. A one-off still earns a lever when the lever is what makes the work checkable. If $principle-laziness-protocol is available, apply it; otherwise build the smallest script that does or proves the job, never a framework.

If $principle-encode-lessons-in-structure is available, use it instead when a recurring instruction needs a durable guardrail; otherwise encode recurring rules in lint, metadata, runtime checks, or automation. This principle is for throughput and reviewability on the work in front of you. If $principle-prove-it-works is available, use its verification guidance; otherwise rerun the lever and inspect the real output directly.

Installs
27
Repository
petalas/skills
GitHub Stars
1
First Seen
Aug 27, 2026