Verifies factual claims in documents using web search and official sources, then proposes corrections with user confirmation. Use when the user asks to fact-check, verify information, validate claims, check accuracy, or update outdated information in documents. Supports AI model specs, technical documentation, statistics, and general factual statements.
60
70%
Does it follow best practices?
Impact
—
No eval scenarios have been run
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./fact-checker/SKILL.mdQuality
Discovery
100%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This is an excellent skill description that clearly communicates what the skill does, when to use it, and what types of content it supports. It uses third person voice consistently, includes natural trigger terms, and carves out a distinct niche around factual verification. The description is concise yet comprehensive, covering capabilities, triggers, and scope without unnecessary verbosity.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple concrete actions: 'verifies factual claims', 'using web search and official sources', 'proposes corrections with user confirmation'. Also specifies supported content types: 'AI model specs, technical documentation, statistics, and general factual statements'. | 3 / 3 |
Completeness | Clearly answers both 'what' (verifies factual claims using web search, proposes corrections) and 'when' (explicit 'Use when...' clause listing multiple trigger scenarios). Also specifies scope of supported document types. | 3 / 3 |
Trigger Term Quality | Includes strong natural trigger terms users would actually say: 'fact-check', 'verify information', 'validate claims', 'check accuracy', 'update outdated information'. These cover common variations of how users would phrase such requests. | 3 / 3 |
Distinctiveness Conflict Risk | The combination of fact-checking, web search verification, and correction proposal creates a clear niche. The specific trigger terms like 'fact-check', 'validate claims', and 'check accuracy' are distinct and unlikely to conflict with general document editing or search skills. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
39%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
The skill has a well-structured workflow with clear sequencing and validation checkpoints, which is its strongest aspect. However, it is severely bloated with explanations of concepts Claude already understands (source evaluation, query construction, handling ambiguity) and packs everything into a single monolithic file. The actionability is moderate—it provides templates and formats but lacks precise tool invocation patterns for the search and edit operations that are central to the task.
Suggestions
Cut the 'Search best practices', 'Source evaluation', 'Handling ambiguity', and 'Limitations' sections entirely or reduce them to 2-3 bullet points each—Claude already knows how to evaluate sources and construct search queries.
Move the examples, special considerations, and quality checklist into a separate reference file (e.g., EXAMPLES.md or REFERENCE.md) and link to them from the main SKILL.md.
Replace the pseudocode Edit() call with the actual tool invocation syntax Claude uses, and add a concrete example of the web search tool call pattern.
Remove the 'When to use' trigger phrases section—this belongs in YAML frontmatter metadata, not in the skill body.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill is extremely verbose at ~200+ lines. It explains concepts Claude already knows (what types of sources are authoritative, how to construct search queries, what 'good' vs 'poor' queries look like). The 'When to use' trigger phrases, source evaluation hierarchy, and handling ambiguity sections all explain things Claude inherently understands. The examples section adds three examples that are essentially abbreviated restatements of the workflow. The 'Limitations' section tells Claude it can't verify opinions or access paywalled content—things it already knows. | 1 / 3 |
Actionability | The workflow steps are reasonably concrete with a comparison table format, status codes, and a report template. However, the Python Edit() example is pseudocode-like (not a real executable API call), and the search strategy is descriptive rather than providing exact tool invocations. The skill describes what to do conceptually but lacks precise tool usage patterns for web search. | 2 / 3 |
Workflow Clarity | The 5-step workflow is clearly sequenced with a progress checklist, explicit validation checkpoints (user approval before applying changes, verification after edits), and a feedback loop (show report → get approval → apply → verify). The quality checklist at the end provides additional verification. The requirement to wait for user confirmation before destructive edits is well-handled. | 3 / 3 |
Progressive Disclosure | The entire skill is a monolithic wall of text with no references to external files. Content like search best practices, source evaluation guidelines, citation formats, and detailed examples could easily be split into separate reference files. Everything is inline, making the skill unnecessarily long for the SKILL.md overview level. No bundle files are provided to support progressive disclosure. | 1 / 3 |
Total | 7 / 12 Passed |
Validation
100%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 11 / 11 Passed
Validation for skill structure
No warnings or errors.
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Table of Contents
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