Verify against code

Skill Fergius-Engineering/instincts/skills/verify-against-code

Working-instinct skills for Claude Code: verify claims against the source, log for the bug you can't reproduce, write like a human, test so the test bites. A reflex layer on top of superpowers.

Install

npx -y skills add Fergius-Engineering/instincts --skill verify-against-code

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

2 stars2 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

What its author says it does

Copied from the file, not written here

Use when about to assert any factual claim about what code or a product does - in an answer, a doc, a commit message, or anything a user will see.

SKILL.md

2.0 KB, as published. Nobody here has run it

The rule

Before you state a fact about what the code or product does, go read the thing that proves it. Your memory, the user's framing, a plan that says "done", a table in the docs — all of these go stale, and stating one as fact when it's wrong costs more than the thirty seconds it takes to check.

Fires when

Answering "does it do X?", writing a doc or README line, writing a commit or PR body, shipping anything outward-facing (store copy, a caption, a before/after), agreeing with a claim the user just made about the code.

How to apply

For each claim, find the concrete artifact that proves it — the symbol, the field, the default value, the line — and read it. Cite what you read as the evidence, briefly.

"It doesn't actually do that" and "only partially" are valid, valuable answers. Say so plainly and surface the conflict instead of going along with the assumption.

Hold this bar even when nobody asked you to check. Especially when nobody asked.

Worked example

A user asks: "Our API trims whitespace from usernames before saving, right?" You remember writing something like that. The cheap move is "yes." The right move: open the save path and read it. You find username.toLowerCase() but no .trim(). The honest answer is "It lowercases, but it does not trim — leading spaces are saved as-is." That gap is exactly the bug the user was about to assume away. The thirty-second read changed a confident wrong answer into a real finding.

Red flags

Thought	Reality
"I'm pretty sure it does that"	Sure isn't read. Open the file.
"The plan says it's done"	Plans go stale. The code is the truth.
"The user said it works that way"	The user can be wrong about their own system. Check.
"It's just a doc line, not code"	A wrong doc line is a wrong claim shipped to every reader.