# How do I create a fact-checking agent skill?

A fact-checking agent skill can be a callable tool you register with an AI agent that takes a claim as input, searches the web for relevant sources, and returns a verdict (supported, contradicted, or unverified) with citations. The critical part is the search step: an LLM reasoning over its training data alone cannot verify recent or domain-specific claims reliably, because the answer depends on what sources actually say right now, not what the model remembers from pretraining.

| Approach                       | Evidence source              | Freshness                       | Returns citations           |
|-------------------------------|------------------------------|---------------------------------|-----------------------------|
| LLM reasoning only            | Training data                | Stale, cutoff-limited           | No                          |
| RAG over internal docs        | Embedded document store       | As fresh as last index         | Yes, from indexed docs      |
| Web search at query time      | Live web                     | Current                         | Yes, from retrieved pages   |
| Dedicated fact-check API      | Curated claim databases      | Varies by provider             | Partial                     |

The minimal skill has three steps: (1) turn the claim into a search query, (2) retrieve the top results with full page content, (3) pass the claim and retrieved content to an LLM with a prompt asking it to assess whether the evidence supports or contradicts the claim. The output is a structured verdict with the source URLs used. Multi-source verification — running the same claim against two or three independent results — reduces the chance of a single biased or outdated source skewing the verdict.

Once the Firecrawl CLI is installed, the search step is a single command:

```
npx -y firecrawl-cli@latest init
firecrawl search "your claim here" --limit 3
```

The CLI returns full page content per result in markdown, which you pipe directly into your agent's context. A minimal shell-based fact-check skill looks like:

[Firecrawl's Search API](https://docs.firecrawl.dev/features/search) returns full page content per result, not just snippets, so the LLM has complete article text to reason against rather than 2-3 sentence extracts that often omit the relevant detail. The CLI also installs as a tool inside Claude Code and other agents that support tool use, so agents can invoke `firecrawl search` directly without any additional wiring.

Last updated: Apr 30, 2026