a-check-that-can-only-confirm SKILL.md skillA
a-check-that-can-only-confirm from synaptiai/synapti-marketplace is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add synaptiai/synapti-marketplace/a-check-that-can-only-confirm@git:20260911.604a89bPins git:20260911.604a89b in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- synaptiai/synapti-marketplace
- Path
plugins/flow/skills/learned/a-check-that-can-only-confirm/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260911.604a89b, committed Sep 11, 2026
- Size
- 4,213 bytes
- Repository stars
- 7
- License
- Apache-2.0
[flow-learned] Design guards, tests, lint rules and verification scripts so they are capable of failing: every check gets a mutant that must make it fire, a mutant that must leave it silent, a mutant that removes its input, and an asserted non-zero count of what it examined. Use this whenever writing or changing anything that walks, greps, scans or asserts across a codebase — a repo-wide test, a claim guard, an identity roster, a seeding check, a CI gate — including when the request is only…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# A Check That Can Only Confirm ## Contract Iron law: a check that cannot fail is not a check — prove it can fire, prove it can stay silent, and prove it reached its input. Applies whenever a guard, test, lint rule, roster walk or scan is written or changed. Returns, per check: a must-fire mutant, a must-stay-silent mutant built from a correct input that resembles the incorrect one, an input-removal mutant, an asserted non-zero count of what was examined, and one run against a real full-size input — each one executed, not just written. Permitted skips: none; a check shipped without the three mutants is unverified. ## Why a green result proves less than it looks A guard has two failure modes and only one is loud. Reporting the wrong answer gets noticed. Reaching nothing does not: zero offending files and zero files examined produce the same green. That happens when the matcher is narrower than intended — matching a number only when a unit follows it, handling two of the four spellings a symbol is imported under — so the input the guard exists for never enters it, and nothing in the output says so. ## Write three mutants, not one …
Read the whole file at its exact version.
How to install
mdr add synaptiai/synapti-marketplace/a-check-that-can-only-confirm@sha256:2beee03490518f38The line at the top of this page pins the label git:20260911.604a89b, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_mt5nhgygtchdaazd)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Sep 11, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (4213 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
synaptiai/synapti-marketplace · 7 stars · license Apache-2.0 · pushed 2026-11-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_mt5nhgygtchdaazd GET https://markdownregistry.com/api/v1/resolve?ref=synaptiai/synapti-marketplace/a-check-that-can-only-confirm GET https://markdownregistry.com/api/v1/blob/2beee03490518f38055c3bd13ef3c3ccd4bb82efe49261412c40953248142c51
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.