If you've ever had your AI say "fixed!" only to find it broke something else, or watched it try the same failed approach four times in a row, this skill exists because of those moments.

Measure Twice is a set of 12 rules, each one written after a specific real mistake. It changes how your agent approaches every task: read the file before editing it, quote the user's exact words instead of summarizing, check that a fix actually worked before moving on.

What it prevents

Jumping straight to code without reading the relevant files first. Paraphrasing your request and losing the specific detail that mattered. Claiming something is done without verifying it. Editing a file without reading its current contents. Trying the same broken fix with slightly different values. Putting changes in the wrong file or scope. Breaking nearby code while fixing something else. Forgetting what you originally asked after a few back and forths.

How it actually works

The agent follows a simple loop: quote your words exactly, read the current state, write one sentence about what needs to change ("Currently X, want Y, changing Z"), then implement. After the change, it re-reads the file and checks that it matches what you asked for instead of just assuming it worked.

Every rule here came from a real session where something went wrong. Nothing theoretical.