# Double Check

> Use when asked “are you sure/certain” or “I don't trust that”; recheck code/files from source and repeat prior analysis in full, not just changes.

- Skill: `tony/double-check-2` (Agent Skill)
- Install (CLI): `npx skillmds@latest add tony/double-check-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tony/double-check-2/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tony (https://skillmd.com/u/tony)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tony/double-check-2

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# Double-check

Re-verify by re-deriving. The deliverable is the verified answer,
not a record of how it differs from your last one.

Read `../../references/verification-contract.md`
before responding — it is the contract this skill enforces.

## Why the obvious response is wrong

Your prior answer sits in the transcript, so re-checking it feels
like editing it: keep the numbering, mark each item *holds* /
*overstated*, report what changed. But transcript order is not
user-adopted state. The user usually has not internalized the prior
answer — often the double-check request is itself the signal that
they never committed to it. A verdict list against text they never
held is unreadable, and inherited scaffolding hides whatever the
first pass missed entirely.

## Steps

1. **Recover the request, not the answer.** From the conversation,
   take the original question, its constraints, and any narrowing the
   user added since. Prior answers of yours are untrusted scratch —
   good for recalling which sources exist, never citable as evidence.
2. **Re-derive from source.** Re-open the artifacts — files, issues,
   specs, data — and rebuild each claim from what they actually say.
   Verification is performed, not asserted: cite what you re-opened
   and what it said, or the command you ran and its output. "Verified
   earlier in this conversation" anchors a claim to transcript
   position and does not count.
3. **Rebuild the structure.** Outline from the source material and
   the request, not from your prior answer's item numbers. A claim
   that no longer earns a place simply does not appear; a missing
   area simply appears.
4. **State confidence on claims.** "Weak evidence — X only follows
   if Y", never "X was overstated".
5. **Check for adopted state.** If the user acted on a prior claim —
   committed, filed, sent, built on it — name that correction
   explicitly, once, briefly. Otherwise the prior turn is not a
   baseline and does not exist in your output.

## Output shape

Same shape the original request implied, as if answering for the
first time. No "what changed" section, no verdict legend, no
*as noted above*. A reader who never saw the first answer must lose
nothing.

When a narrow request ("are you sure about X?") scopes the answer to
X, still append anything material you discovered while re-deriving —
as a standalone fact about the subject ("the ADR also permits Y"),
never as a correction of your prior answer. Scoping down the answer
must not scope down what the user learns.