---
name: fact-check
license: MIT
metadata:
  author: CyranoB
  version: "1.2.1"
description: >
  Fact-check a specific, verifiable claim by seeking supporting and contradicting
  evidence, weighing source quality, and issuing a calibrated verdict with citations.
---

# Fact Check

Test a specific claim against evidence on both sides and issue a calibrated verdict.

## Tools

Before using tools, read [source-access.md](source-access.md) completely.

Use available web search and URL-fetch tools. Prefer callable names ending in
`duckduckgo_search` and `web_fetch`; client-added prefixes vary, so inspect the tools in
the session. Without session tools, run the packaged CLI in an isolated environment:

```bash
uvx --python '>=3.10,<3.14' web-forager search "your query" --max-results 8 --output-format json
uvx --python '>=3.10,<3.14' web-forager fetch "https://example.com" --format markdown
```

If `uvx` cannot run packaged search, use `ddgs` without touching the current project
environment:

```bash
uv run --no-project --python '>=3.10,<3.14' --with 'ddgs>=9.5.2' python - <<'PY'
from ddgs import DDGS
results = DDGS().text(query="your query", max_results=8)
for r in results:
    print(r["title"], r["href"], r["body"])
PY
```

If packaged fetch fails, use Jina Reader:

```bash
curl -s "https://r.jina.ai/https://example.com"
```

The workflow requires both search and fetch. If either capability is unavailable,
return `UNVERIFIED` and name the missing capability.

## Workflow

### 1. Extract the claims

Turn the user's statement into specific, independently verifiable claims. Separate
compound claims. If wording is subjective, explain that it can be contextualized but
cannot receive a factual verdict. Continue immediately when the claim is clear; ask for
confirmation only when two plausible interpretations would change the evidence sought.

**Complete when:** every factual claim is precise enough that contrary evidence could
disprove it.

### 2. Seek support

Search for primary evidence that would confirm each claim. Use direct paraphrases,
official statements, and queries for the exact metric or event.

**Complete when:** each claim has the strongest available supporting evidence, or the
absence of support is recorded.

### 3. Seek contradiction

Actively search for counterevidence, corrections, alternative measurements, and credible
disagreement. Do not treat failure to find a debunk as confirmation.

**Complete when:** every claim has received a genuine adversarial search, not merely a
second confirming query.

### 4. Read and weigh sources

Read 2–4 of the most authoritative sources across both sides. Evaluate authority,
specificity, recency, independence, and conflicts of interest.

**Complete when:** the decisive evidence addresses the exact claim and all material
source limitations are known.

### 5. Deliver the verdict

Use this scale:

- **CONFIRMED:** multiple authoritative sources agree and no credible contradiction
  survives review.
- **LIKELY TRUE:** strong support remains, with minor gaps or caveats.
- **UNVERIFIED:** strong evidence is unavailable in either direction.
- **DISPUTED:** credible sources materially disagree.
- **FALSE:** strong evidence contradicts the claim and support is weak or absent.

Default to a compact verdict for one claim:

1. state the claim and verdict first;
2. explain the decisive support and contradiction in 2–4 sentences;
3. add only caveats that could change how the verdict is understood;
4. cite 2–4 decisive sources, annotated by role.

For multiple extracted claims, repeat the compact block for each. Use a source-by-source
account only when the user requests it or a material conflict cannot be explained
compactly. State explicitly when one side produced no evidence.

**Complete when:** every extracted claim has a verdict, both search directions are
accounted for, decisive evidence is cited, and confidence matches the limitations.