Visual Fact Check

---
name: visual-fact-check
description: 'Use when invoked as visual-fact-check with a document path. Verifies every factual claim against its cited sources, corrects errors in place, and appends a verification summary. Not for both-ways fact-checking of assertions — use verify-both-ways.'
---

# Visual fact check

## Contract

| Field | Bound contract |
|---|---|
| Trigger | A document path, defaulting to the most recently modified HTML in the diagrams directory |
| Authority | Reversible, local mutations only. No remote resources mutated. |
| Side effect | Corrects factual errors in the target document in place; appends a verification summary of what was checked and changed |
| Done | Every verifiable claim classified verified, corrected, unsupported, or unverifiable; document structure preserved |

## Inputs

- **Document path** — an explicit document path or, when omitted, the most recently modified HTML file inside a `diagrams` directory below the working directory.
- **Cited sources** — the links, references, and source notes already attached to claims in the document.

## Procedure

1. Resolve the document path. If the caller did not supply one, select the most recently modified HTML file inside a `diagrams` directory below the working directory. If none exists, return `document-not-found` without writing. **Done when:** the document path is resolved or `document-not-found` is returned.
2. Read the complete document and record its element structure before mutation. **Done when:** the element structure is recorded.
3. Extract every factual assertion from paragraphs, list items, captions, table cells, and alternative text. Bind each assertion to its cited source or mark it uncited. **Done when:** every assertion is extracted and bound to a source or marked uncited.
4. Retrieve each cited source with the available web search and read tools. Prefer the cited primary source. A failed retrieval is evidence of `unverifiable`, never permission to substitute a different claim. **Done when:** every cited source is retrieved or marked `unverifiable`.
5. Classify each assertion against the gathered evidence: `verified` (cited evidence supports the claim), `corrected` (cited evidence contradicts and supplies a supported correction), `unsupported` (cited source does not support the claim), `unverifiable` (no usable citation or evidence cannot be retrieved). **Done when:** every assertion has one classification.
6. Correct only claims classified `corrected`. Preserve surrounding structure and record the exact before and after text. Do not invent corrections for unsupported or unverifiable claims. **Done when:** every `corrected` claim is fixed with before/after text recorded.
7. Append one HTML verification summary that lists every claim, citation, classification, and correction. Escape inserted text for the target context. **Done when:** the verification summary is appended.
8. Validate that tags remain balanced and the pre-existing element and attribute structure is unchanged except for corrected text nodes and the appended summary. If validation fails, restore the preserved document bytes. **Done when:** structural validation passes or the document is restored.

## Failure and recovery

- **document-not-found** — return blocked without creating or guessing a path.
- **source-unavailable** — classify only the affected claim as `unverifiable`; continue with independent claims.
- **structure-corrupted** — restore the exact pre-mutation document bytes and report the failed structural assertion.
- **partial result** — finish every claim whose cited evidence is available and list the remaining claims as unsupported or unverifiable. Never report them as verified.

## Output
The target document with evidence-backed corrections and one appended verification summary; the returned report lists each claim, citation, classification, before/after text when corrected, and the structural-integrity result.