fact-check

fact-check is a skill for Claude Code from KingGyuSuh/gemini-search-cc. It costs 16 tokens per session (393 once invoked), scanned A, original, Apache-2.0.

A fact-checking workflow that uses current Google Search results through the Antigravity command-line tool.

In plain words
What is it for?
Check claims in code comments, documentation, Stack Overflow answers, or conversations and report the resulting verdict.
Why use it?
It helps verify technical claims against external sources instead of relying on possibly outdated assumptions.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: names the AskUserQuestion tool.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the gemini plugin — 9 skills, 3 hooks shipped together

Good fit Check claims in code comments, documentation, Stack Overflow answers, or conversations and report the resulting verdict.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add KingGyuSuh/gemini-search-cc
Claude Code
/plugin install gemini

Made for: Claude Code.

Or install gemini, the plugin that ships this one along with the rest of its 9 skills, 3 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-check

README.md
[![agentmods](https://agentmods.dev/badge/skills/kinggyusuh/gemini-search-cc/fact-check/github.svg)](https://agentmods.dev/skills/kinggyusuh/gemini-search-cc/fact-check)
Your own site
<a href="https://agentmods.dev/skills/kinggyusuh/gemini-search-cc/fact-check"><img src="https://agentmods.dev/badge/skills/kinggyusuh/gemini-search-cc/fact-check/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-check

Your own site · 80×15
<a href="https://agentmods.dev/skills/kinggyusuh/gemini-search-cc/fact-check"><img src="https://agentmods.dev/badge/skills/kinggyusuh/gemini-search-cc/fact-check.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 393 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 $0.00016 $0.00393
Opus 5 $0.00008 $0.00197
Sonnet 5 $0.00003 $0.00079
Haiku 4.5 $0.00002 $0.00039

Measured 11d ago against content hash 96647e6036c8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

fact-check 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 11d 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.

plugins/gemini/skills/fact-check/SKILL.md · 42 lines

What it actually says

Verify a technical claim, assumption, or statement using the Antigravity CLI's real-time grounded Google Search.

Use this when you encounter claims in code comments, documentation, Stack Overflow answers, or conversation that need verification against current, authoritative sources.

Raw slash-command arguments: $ARGUMENTS

Steps

  1. If $ARGUMENTS is empty, use AskUserQuestion to ask what claim to verify.

  2. Run the companion script:

    node "${CLAUDE_PLUGIN_ROOT}/scripts/gemini-companion.mjs" factcheck "$ARGUMENTS"
    
  3. If the command fails with a non-zero exit code:

    • Run node "${CLAUDE_PLUGIN_ROOT}/scripts/gemini-companion.mjs" setup to diagnose.
    • Show the diagnosis to the user and stop.
  4. Return the command output verbatim to the user.

  5. After the results, provide a Fact-Check Verdict:

    • Verdict: Confirmed / Partially True / Misleading / False / Unverifiable
    • Confidence: High / Medium / Low (based on source agreement)
    • Key Correction: If the claim was wrong, state the correct information with source

Constraints

  • Do not paraphrase the search output.
  • Do not speculate beyond what the search results show.
  • If sources disagree, present both sides and note the disagreement.
  • Always cite the sources that support or refute the claim.
  • If the claim cannot be verified through search, say so explicitly — do not guess.
  • Distinguish between "no evidence found" and "evidence contradicts the claim."
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. 11d ago First seen · 42 lines · 16 tokens per session scan A 96647e6036c8

Subscribe to this mod's changes

fact-check is a skill published in the GitHub repository KingGyuSuh/gemini-search-cc (3 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 16 tokens to every session and 393 once invoked, about $0.0001 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 2026-08-31.

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