fact-checker
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 Use when the user asks to fact-check, verify information, validate claims, check accuracy, or update outdated information in documents.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.
Install with Tessl CLI
npx tessl i github:fernandezbaptiste/claude-code-skills --skill fact-checker90
Does it follow best practices?
If you maintain this skill, you can automatically optimize it using the tessl CLI to improve its score:
npx tessl skill review --optimize ./path/to/skillValidation for skill structure
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 a well-crafted skill description that excels across all dimensions. It clearly articulates specific capabilities (verification via web search, proposing corrections), includes an explicit 'Use when...' clause with natural trigger terms, and defines its scope with supported content types. The description is distinctive enough to avoid conflicts with related skills like general web search or document editing.
| 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 claims using web search, proposes corrections) and when (explicit 'Use when...' clause with multiple trigger scenarios). Also specifies scope of supported document types. | 3 / 3 |
Trigger Term Quality | Excellent coverage of natural terms users would say: 'fact-check', 'verify information', 'validate claims', 'check accuracy', 'update outdated information'. These are all phrases users would naturally use when needing this skill. | 3 / 3 |
Distinctiveness Conflict Risk | Clear niche focused specifically on fact-checking and verification with distinct triggers like 'fact-check', 'validate claims', 'check accuracy'. Unlikely to conflict with general document editing or web search skills due to the specific verification focus. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
77%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This is a well-structured, actionable skill with excellent workflow clarity and explicit user approval checkpoints for destructive operations. The main weaknesses are moderate verbosity (explaining concepts Claude already knows like what subjective content is) and keeping all content inline rather than using progressive disclosure for the lengthy reference sections.
Suggestions
Remove the 'Skip subjective content' section - Claude already knows to focus on verifiable claims without being told to skip opinions
Move 'Search best practices' and 'Special considerations' sections to a separate REFERENCE.md file, keeping only essential guidance in the main skill
Remove or condense the 'When to use' section since trigger phrases should be handled by frontmatter, not duplicated in the body
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill is reasonably efficient but includes some unnecessary content like explaining what types of claims to skip (Claude knows this) and overly detailed examples. The 'When to use' section duplicates information that should be in frontmatter triggers. | 2 / 3 |
Actionability | Provides concrete, executable guidance including specific search queries, comparison table format, structured report template, and actual Edit tool usage with Python syntax. Examples are specific and copy-paste ready. | 3 / 3 |
Workflow Clarity | Excellent multi-step workflow with explicit checklist, clear sequencing (1-5 steps), and critical validation checkpoint requiring user approval before applying changes. Includes verification step after corrections and quality checklist. | 3 / 3 |
Progressive Disclosure | Content is well-organized with clear sections, but the skill is quite long (~250 lines) and could benefit from splitting detailed examples or the search best practices into separate reference files. All content is inline rather than appropriately distributed. | 2 / 3 |
Total | 10 / 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.
- Reviewed
Table of Contents
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