fact-checker

fact-checker is a skill for Claude Code, Codex from nicepkg/ai-workflow. It costs 64 tokens per session (1,948 once invoked), scanned A, original, MIT.

A document-checking guide that verifies factual claims against web searches and official sources. It covers technical specifications, versions, dates, statistics, API limits, and benchmark results while leaving opinions and explanations alone.

In plain words
What is it for?
Use it to review technical documents, identify claims that need checking, compare them with reliable sources, and prepare a correction report.
Why use it?
It helps find inaccurate or outdated statements and supports proposed corrections with authoritative evidence. Changes are made only after user confirmation.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/nicepkg/ai-workflow/fact-checker
Any agent
npx skills add nicepkg/ai-workflow --skill fact-checker
Clone the repo
git clone --depth 1 https://github.com/nicepkg/ai-workflow

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for fact-checker

README.md
[![agentmods](https://agentmods.dev/badge/skills/nicepkg/ai-workflow/fact-checker.svg)](https://agentmods.dev/skills/nicepkg/ai-workflow/fact-checker)
Your own site
<a href="https://agentmods.dev/skills/nicepkg/ai-workflow/fact-checker"><img src="https://agentmods.dev/badge/skills/nicepkg/ai-workflow/fact-checker.svg" alt="Measured on agentmods" height="20"></a>
Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,948 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00064 $0.01948
Opus 5 $0.00032 $0.00974
Sonnet 5 $0.00013 $0.00390
Haiku 4.5 $0.00006 $0.00195

Measured 3d ago against content hash 898b569d4a2c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fact-checker scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

workflows/content-creator-workflow/.claude/skills/fact-checker/SKILL.md · 284 lines

How it starts

The opening of the file, as written. The whole thing — 284 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fact Checker

Verify factual claims in documents and propose corrections backed by authoritative sources.

When to use

Trigger when users request:

  • "Fact-check this document"
  • "Verify these AI model specifications"
  • "Check if this information is still accurate"
  • "Update outdated data in this file"
  • "Validate the claims in this section"

Workflow

Copy this checklist to track progress:

Fact-checking Progress:
- [ ] Step 1: Identify factual claims
- [ ] Step 2: Search authoritative sources
- [ ] Step 3: Compare claims against sources
- [ ] Step 4: Generate correction report
- [ ] Step 5: Apply corrections with user approval

Step 1: Identify factual claims

Scan the document for verifiable statements:

Target claim types:

  • Technical specifications (context windows, pricing, features)
  • Version numbers and release dates
  • Statistical data and metrics
  • API capabilities and limitations
  • Benchmark scores and performance data

Skip subjective content:

  • Opinions and recommendations
  • Explanatory prose
  • Tutorial instructions
  • Architectural discussions

Step 2: Search authoritative sources

For each claim, search official sources:

AI models:

  • Official announcement pages (anthropic.com/news, openai.com/index, blog.google)
  • API documentation (platform.claude.com/docs, platform.openai.com/docs)
  • Developer guides and release notes

Technical libraries:

  • Official documentation sites
  • GitHub repositories (releases, README)
  • Package registries (npm, PyPI, crates.io)

General claims:

  • Academic papers and research
  • Government statistics
  • Industry standards bodies

Search strategy:

  • Use model names + specification (e.g., "Claude Opus 4.5 context window")
  • Include current year for recent information
  • Verify from multiple sources when possible

Step 3: Compare claims against sources

Create a comparison table:

Claim in Document Source Information Status Authoritative Source
Claude 3.5 Sonnet: 200K tokens Claude Sonnet 4.5: 200K tokens ❌ Outdated model name platform.claude.com/docs
GPT-4o: 128K tokens GPT-5.2: 400K tokens ❌ Incorrect version & spec openai.com/index/gpt-5-2

Read the full file on GitHub · 284 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 284 lines · 64 tokens per session scan A 898b569d4a2c

Subscribe to this mod's changes

fact-checker is a skill published in the GitHub repository nicepkg/ai-workflow (283 stars, last pushed 7mo ago), licensed MIT. It adds 64 tokens to every session and 1,948 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories

openrouter-video-generator

Generate or declare an OpenRouter video asset for AwesomeWebpageMetaSkill using a parent-leased Provider Settings connection and configured non-secret model/output values.

opensquilla/opensquilla · 35 tokens

nano-banana-pro-openrouter

Deterministic OpenRouter image generation adapter for Nano Banana Pro / Gemini image models. Use as skillexec when a meta-skill needs local image files and structured IMAGEREADY records without spawning an LLM agent.

opensquilla/opensquilla · 49 tokens

skill-creator-linter

Internal tool (not user-invocable). Called by meta-skill-creator as a DAG step (kind: agent) to lint a candidate meta-skill SKILL.md against G1 (parse + reference check + xmlescape grep + structural lint) and G2 (scheduler dry-run with stub executors). Deterministic, sub-second, no LLM. Returns JSON diagnostics.

opensquilla/opensquilla · 84 tokens

llm-redteam-overview

LLM red team category — full AATMF v3 tactic coverage (T01–T15). Routing skill: read this first to identify which tactic applies, then load the matching sub-skill. Maps to MITRE ATLAS where overlap exists.

PurpleAILAB/Decepticon · 58 tokens

aatmf-t10-confidentiality-breach

AATMF T10 — Integrity & Confidentiality Breach. System prompt extraction, training-data extraction, model-weight leakage, private-key recovery.

PurpleAILAB/Decepticon · 39 tokens

aatmf-t15-human-ai-coupling

AATMF T15 — Human-AI Coupling. Deepfake escalation, voice clone vishing, deepfake-image-driven social engineering, automation of human-targeted attacks.

PurpleAILAB/Decepticon · 45 tokens