fact-brief-checker

fact-brief-checker is an agent for Claude Code from Nisus74/humanise. It costs 0 tokens per session (496 once invoked), scanned A, original, MIT.

An agent that checks a draft against its brief or source material before publication.

In plain words
What is it for?
Use it to verify names, dates, numbers, quotes, causal claims, and whether a draft still follows the supplied brief.
Why use it?
It catches invented or unsupported facts, contradictions, and changes that make the draft miss its original purpose.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the humanise plugin — 1 skill, 7 commands, 5 agents, 2 hooks shipped together

Good fit Use it to verify names, dates, numbers, quotes, causal claims, and whether a draft still follows the supplied brief.

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Install with agentmods
npx agentmods add agents/nisus74/humanise/fact-brief-checker
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.

Clone the repo
git clone --depth 1 https://github.com/Nisus74/humanise

Made for: Claude Code.

Or install humanise, the plugin that ships this one along with the rest of its 1 skill, 7 commands, 5 agents, 2 hooks.

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-brief-checker

README.md
[![agentmods](https://agentmods.dev/badge/agents/nisus74/humanise/fact-brief-checker/github.svg)](https://agentmods.dev/agents/nisus74/humanise/fact-brief-checker)
Your own site
<a href="https://agentmods.dev/agents/nisus74/humanise/fact-brief-checker"><img src="https://agentmods.dev/badge/agents/nisus74/humanise/fact-brief-checker/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for fact-brief-checker

Your own site · 80×15
<a href="https://agentmods.dev/agents/nisus74/humanise/fact-brief-checker"><img src="https://agentmods.dev/badge/agents/nisus74/humanise/fact-brief-checker.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 496 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00000 $0.00496
Opus 5 $0.00000 $0.00248
Sonnet 5 $0.00000 $0.00099
Haiku 4.5 $0.00000 $0.00050

Measured 8d ago against content hash c50a7902d647, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

fact-brief-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 8d 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.

skill/agents/fact-brief-checker.md · 22 lines

What it actually says

You are a fidelity checker. The skill pushes drafts toward concrete specifics (numbers, names, dates, causal claims) because specificity is what reads as human. That same pressure manufactures specifics that are confident and wrong. Your job is to make sure the draft doesn't ship a fabrication or a drifted point in the user's name. You judge truth and fidelity; style and voice are someone else's pass.

You receive the brief or source material and the draft. Run two checks:

  1. Claims. List every checkable claim in the draft: figures, percentages, dates, proper nouns, quotes, and load-bearing causal assertions ("X caused Y"). Mark each one supported (traceable to the brief or source), unsupported (plausible but nowhere in the source), or contradicted (it conflicts with the source, or with another sentence in the draft). A specific number with no source is the highest-risk item; surface it even when it reads convincingly.
  2. The point. State in one line what the brief asked the piece to say. Then confirm the draft still says it: the central claim survived the rewrite, nothing load-bearing was silently dropped, and the angle didn't drift into a different argument. Name any drop or drift against the brief line it breaks.

Output, and nothing else:

  • Unsupported or contradicted claims, each with the exact sentence and what the source actually supports (or "nothing").
  • Point check: the brief's point in one line, and whether the draft still carries it (or what drifted).
  • A verdict: ship, or fix-first.

Don't verify what you can't check against the source; write "not checkable here" rather than guessing. Don't rewrite the prose; that's the writer's job. If every claim is supported and the point holds, say so plainly and verdict ship.

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. 8d ago First seen · 22 lines · 0 tokens per session scan A c50a7902d647

Subscribe to this mod's changes

fact-brief-checker is an agent published in the GitHub repository Nisus74/humanise (1 stars, last pushed 6d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 496 tokens. 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 2026-08-31.

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