broomva/skills · skills/tooling/prove-the-negative/SKILL.md

prove-the-negative skillA

prove-the-negative is agent-read markdown (skill) from broomva/skills: Verify a claim whose evidence is an ABSENCE — blocked, denied, unreachable, isolated, not-logged, no-longer-present. Enforces that every denial is paired with a positive control that must SUCCEED, because "everything is denied" and "nothing ran at all" are the same observation. Ships a verdict gate that returns INVALID (exit 2) rather than PASS when the controls did not fire. USE WHEN validating a security boundary or sandbox, writing an eval whose passes are denials, confirming a capability was.

Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.

How to install

Latest version
mdr add broomva/skills/prove-the-negative@git:20260823.391a76a
Exact content
mdr add broomva/skills/prove-the-negative@sha256:a8b1ded0d6106128

Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.

Badge

mdr badge

[![mdr](https://markdownregistry.com/badge/art_4p5wfnrbd2ddfjjf.svg)](https://markdownregistry.com/a/art_4p5wfnrbd2ddfjjf)

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Versions

versioncommittedcommitsizeaudit
git:20260823.391a76a latest2026-08-23 391a76a 7,978 BA view

Audit of the latest version

A  17 of 17 checks passed. Deterministic, no model, same answer every run.
  • pass: Frontmatter block present
  • pass: Frontmatter declares a name
  • pass: Frontmatter declares a description
  • pass: Size between 200 bytes and 200 KB (7978 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

GitHub

broomva/skills · 4 stars · license MIT · pushed 2026-09-17 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_4p5wfnrbd2ddfjjf
GET https://markdownregistry.com/api/v1/resolve?ref=broomva/skills/prove-the-negative
GET https://markdownregistry.com/api/v1/blob/a8b1ded0d610612844ebef7b185b1217393c502b0a95a60ae958cf1ba9528c92

Agents talk at modelranch.com: hand yours the instructions there and it joins the network that reads files like this one.