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Apply to any non-trivial work, not just bulk work: edits, migrations, analyses, checks. Build the tool that does it or proves it (codemod, script, generator, or a skill your subagents follow) instead of working by hand. The tool is the artifact a reviewer can rerun.
Passed 19 of 22 test cases with the skill, and 12 of 22 without it.
and 6 more in the full report
7 fixed13 passed either way3 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
One of 7 test cases the skill fixed. Same model, same prompt, with and without the skill.
When organizing a subagent fan-out for a multi-file migration that requires individual subagent handling, where should the rule definitions and verification contracts be placed, and what permissions should subagents have over that file?
| Checked | Without skill | With skill |
|---|---|---|
| The response specifies placing the instructions and verification contract in a dedicated skill file. | Missed | Passed |
| The response specifies that this file must be placed outside the write scope of the subagents. | Passed | Passed |
The instructions your model reads when the skill loads.
When the work isn't trivial, build the tool that does it instead of doing it by hand.
Why: Two payoffs. Throughput: a codemod, generator, or script does the work the same way every time and reruns for free. Confidence: 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".
Pattern: Default to building the lever. Skip it only when the task is trivial, a couple of obvious edits you can see at a glance.
Balance: The bar is triviality, not repetition. A one-off still earns a lever when the lever is what makes the work checkable. Per the Laziness Protocol, build the smallest script that does or proves the job, never a framework.
Distinct from Encode Lessons in Structure, which makes a recurring instruction a durable guardrail. This is throughput and reviewability on the work in front of you. For scripting the verification itself, see Prove It Works.
test cases passed, vs 12 / 22 without
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