fact-check

name	fact-check
description	Verify a specific claim by searching for evidence across web and academic sources. Use when the user asks to verify, fact-check, or confirm a statement.
argument-hint	["claim to verify"]
allowed-tools	Bash, Read, Glob, Grep, Write

Fact-check the following claim: "$ARGUMENTS"

1. Decompose

Break the claim into specific, verifiable sub-claims. List them explicitly before searching.

2. Search for Evidence

For each sub-claim:

paper-search google web "<sub-claim as question>"
paper-search semanticscholar snippets "<sub-claim keywords>"
paper-search semanticscholar papers "<sub-claim keywords>" --limit 5

3. Verify Sources

For each promising source:

paper read <arxiv_id> <relevant section>   # for academic papers
paper-search browse <url>                   # for web pages

Prefer primary sources (original papers, official data) over secondary reports.

4. Assess

For each sub-claim, assign a verdict:

• Supported: strong evidence from multiple reliable sources
• Partially supported: some evidence, with caveats
• Unsupported: no evidence found, or evidence contradicts the claim
• Uncertain: insufficient evidence to judge

5. Report

Present:

• The original claim
• Each sub-claim with its verdict and supporting evidence
• An overall assessment
• All sources cited with URLs

Guidelines

• Always cite specific sources — never state a verdict without evidence.
• Distinguish between "no evidence found" and "evidence contradicts."
• Note the quality and recency of sources.
• If a claim is about a specific paper, read that paper directly rather than relying on summaries.