How do I install the Fact Check skill?

Run npx skillmds@latest add amethystluna/fact-check in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Fact Check safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Fact Check?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Fact Check free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Fact Check?

AmethystLuna (@amethystluna) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Fact Check by amethystluna — Agent Skill

Name: Fact Check
Author: AmethystLuna

Fact Check

Use when reviewing design documents, architecture specs, technical proposals, or plans that make claims about API names, file paths, enum values, counts, or mechanism feasibility — a lightweight claim-by-claim check against the codebase with evidence. Built into embedded-workbench as the fallback when the full logicprobe plugin is not installed. NOT for state machines, protocol/retry logic, or 'always'/'never' behavioral claims that need executable model verification — those require the logicprobe plugin.

AmethystLuna a4ee9a0 2.5 KB Updated Sep 17, 2026

File contents

Fact Check (fallback)

Lightweight claim verification built into this plugin. Use it when the full logicprobe plugin is not installed — it checks every verifiable claim in a document/plan against the codebase with evidence, without model escalation.

When to use

Design docs, architecture specs, technical proposals, refactoring plans that name APIs, types, files, enums, counts, or mechanisms.
Proactively when a plan will be approved (plan-mode gate) and logicprobe is unavailable.

What to verify (per claim)

Claim type	Method
Numeric claims (counts, sizes, frequencies)	`grep -c` / `grep -rn`
API/type/enum names	Extract actual signatures/values from headers
File paths and line numbers	Confirm existence and content
Mechanism feasibility	Check language standard / compiler support

Process

Enumerate every verifiable claim (quote it verbatim).
Verify each against the codebase with evidence (file:line + excerpt).
Output per claim: claim → evidence → verdict.

Output format

Claim:
Evidence: <file:line + grep/read excerpt>
Verdict: confirmed | refuted | unverifiable
Correction direction (when refuted) — never fix inline.

Append a ## Plan Verification block:

## Plan Verification
- **Mode**: fact-check (fallback — logicprobe plugin not installed)
- **Claims checked**: [N] confirmed, [M] refuted, [K] unverifiable
- **Escalation**: model verification NOT run (requires logicprobe plugin)

Boundaries

No executable model verification — no state-space exploration, no harness.
State machines (≥3 states), ACK/NACK/retry/timeout logic, lock/unlock ordering, and "always"/"never"/"guaranteed" claims require the logicprobe plugin: install it (see .dsh/INSTALL.md) or tell the user verification is degraded to manual mode for those claims.
Checking a claim is not a security audit; being checked ≠ being safe.

---name: fact-checkdescription: Use when reviewing design documents, architecture specs, technical proposals, or plans that make claims about API names, file paths, enum values, counts, or mechanism feasibility — a lightweight claim-by-claim check against the codebase with evidence. Built into embedded-workbench as the fallback when the full logicprobe plugin is not installed. NOT for state machines, protocol/retry logic, or 'always'/'never' behavioral claims that need executable model verification — those require the logicprobe plugin.---# Fact Check (fallback)Lightweight claim verification built into this plugin. Use it when the full`logicprobe` plugin is not installed — it checks every verifiable claim in adocument/plan against the codebase with evidence, without model escalation.## When to use- Design docs, architecture specs, technical proposals, refactoring plans that name APIs, types, files, enums, counts, or mechanisms.- Proactively when a plan will be approved (plan-mode gate) and logicprobe is unavailable.## What to verify (per claim)| Claim type | Method ||-----------|--------|| Numeric claims (counts, sizes, frequencies) | `grep -c` / `grep -rn` || API/type/enum names | Extract actual signatures/values from headers || File paths and line numbers | Confirm existence and content || Mechanism feasibility | Check language standard / compiler support |## Process1. Enumerate every verifiable claim (quote it verbatim).2. Verify each against the codebase with evidence (file:line + excerpt).3. Output per claim: claim → evidence → verdict.## Output format- **Claim**: <verbatim quote>- **Evidence**: <file:line + grep/read excerpt>- **Verdict**: confirmed | refuted | unverifiable- **Correction direction** (when refuted) — never fix inline.Append a `## Plan Verification` block:```markdown## Plan Verification- **Mode**: fact-check (fallback — logicprobe plugin not installed)- **Claims checked**: [N] confirmed, [M] refuted, [K] unverifiable- **Escalation**: model verification NOT run (requires logicprobe plugin)```## Boundaries- **No executable model verification** — no state-space exploration, no harness.- State machines (≥3 states), ACK/NACK/retry/timeout logic, lock/unlock ordering, and "always"/"never"/"guaranteed" claims require the `logicprobe` plugin: install it (see `.dsh/INSTALL.md`) or tell the user verification is degraded to manual mode for those claims.- Checking a claim is not a security audit; being checked ≠ being safe.

Frequently asked questions