fact-checker

fact-checker is an agent for Claude Code from buriedsignals/spotlight. It costs 13 tokens per session (5,121 once invoked), scanned A, original, no licence file.

An agent that independently checks investigation findings using SIFT, a fact-checking method for stopping, investigating the source, finding better coverage, and tracing claims to their origin.

In plain words
What is it for?
It helps verify sources, trace claims to original material, and assess whether investigation findings are supported.
Why use it?
It adds a separate verification pass so findings are not accepted only because they appear plausible.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the spotlight plugin — 25 skills, 2 agents shipped together

Good fit It helps verify sources, trace claims to original material, and assess whether investigation findings are supported.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/buriedsignals/spotlight/fact-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/buriedsignals/spotlight

Made for: Claude Code.

Or install spotlight, the plugin that ships this one along with the rest of its 25 skills, 2 agents.

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/agents/buriedsignals/spotlight/fact-checker.svg)](https://agentmods.dev/agents/buriedsignals/spotlight/fact-checker)
Your own site
<a href="https://agentmods.dev/agents/buriedsignals/spotlight/fact-checker"><img src="https://agentmods.dev/badge/agents/buriedsignals/spotlight/fact-checker.svg" alt="Measured on agentmods" height="20"></a>
Per session 13 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 5,121 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.00013 $0.05121
Opus 5 $0.00006 $0.02560
Sonnet 5 $0.00003 $0.01024
Haiku 4.5 $0.00001 $0.00512

Measured 8d ago against content hash ba4fd8cc9ddd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

fact-checker scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- **I — Investigate the source.** Who runs it? What is their track record, expertise, and potential bias? Check the About page, editorial standards, named authors, institutional affiliations. For domain-age checks, invok
agents/fact-checker.md · 332 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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 · 332 lines · 13 tokens per session scan A ba4fd8cc9ddd

Subscribe to this mod's changes

fact-checker is an agent published in the GitHub repository buriedsignals/spotlight (39 stars, last pushed 5d ago), with no licence file. It adds 13 tokens to every session and 5,121 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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