cors-policy-validator
Cors Policy Validator - Auto-activating skill for Security Fundamentals. Triggers on: cors policy validator, cors policy validator Part of the Security Fundamentals skill category.
36
3%
Does it follow best practices?
Impact
98%
0.98xAverage score across 3 eval scenarios
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./planned-skills/generated/03-security-fundamentals/cors-policy-validator/SKILL.mdQuality
Discovery
7%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 description is extremely weak, essentially just restating the skill name and category without providing any meaningful information about capabilities or usage triggers. It fails to describe what the skill does, when it should be used, or what user requests should activate it. Claude would struggle to select this skill appropriately from a list of available skills.
Suggestions
Add concrete actions the skill performs, e.g., 'Validates CORS policy configurations, checks Access-Control headers for security misconfigurations, and identifies overly permissive origin allowlists.'
Add an explicit 'Use when...' clause with natural trigger terms, e.g., 'Use when the user asks about CORS headers, cross-origin resource sharing policies, Access-Control-Allow-Origin configuration, or debugging CORS errors.'
Remove the duplicate trigger term 'cors policy validator' and replace with varied natural language terms users would actually say, such as 'CORS configuration', 'cross-origin policy', 'CORS headers', 'CORS security'.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | The description provides no concrete actions. It says 'Cors Policy Validator' but never describes what it actually does—no mention of validating, checking, analyzing, or any specific operations on CORS policies. | 1 / 3 |
Completeness | Neither 'what does this do' nor 'when should Claude use it' is meaningfully answered. The description only states the skill name and category without explaining functionality or explicit usage triggers. | 1 / 3 |
Trigger Term Quality | The only trigger terms listed are 'cors policy validator' repeated twice. It misses natural user phrases like 'CORS headers', 'cross-origin', 'Access-Control-Allow-Origin', 'CORS configuration', or 'CORS errors'. | 1 / 3 |
Distinctiveness Conflict Risk | The term 'CORS policy validator' is somewhat specific to a niche domain, which reduces conflict risk with unrelated skills. However, the lack of detail about what it does versus other security-related skills still creates some overlap potential. | 2 / 3 |
Total | 5 / 12 Passed |
Implementation
0%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill is an empty template with no actual content about CORS policy validation. It contains only boilerplate section headers and generic descriptions that could apply to any skill, providing zero actionable guidance on validating CORS policies, identifying misconfigurations, or implementing secure CORS headers.
Suggestions
Add concrete CORS validation logic, such as a Python or JavaScript function that checks an Origin header against an allowlist and returns appropriate Access-Control-Allow-Origin headers.
Include specific examples of dangerous CORS misconfigurations (e.g., wildcard origins with credentials, null origin reflection, regex bypass patterns) and how to detect them.
Provide a clear workflow: 1) Extract CORS headers from response, 2) Check against security rules (list them), 3) Report findings with severity levels, with example input/output.
Remove all meta-description sections ('Purpose', 'When to Use', 'Example Triggers') that add no technical value and replace with actionable content like validation rules, code snippets, and a checklist of CORS security best practices.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The content is entirely filler and boilerplate. It explains nothing Claude doesn't already know, repeats 'cors policy validator' excessively, and provides zero actual technical content about CORS policy validation. | 1 / 3 |
Actionability | There are no concrete code examples, commands, validation rules, or specific CORS configurations. The skill describes what it could do rather than providing any executable or actionable guidance. | 1 / 3 |
Workflow Clarity | No workflow, steps, or process is defined. The skill mentions 'step-by-step guidance' and 'validates outputs' but provides neither steps nor validation criteria. | 1 / 3 |
Progressive Disclosure | The content is a flat, uninformative page with no references to detailed materials, no examples, and no structured navigation to deeper content. The sections present are all meta-descriptions with no substance. | 1 / 3 |
Total | 4 / 12 Passed |
Validation
81%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 9 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
allowed_tools_field | 'allowed-tools' contains unusual tool name(s) | Warning |
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
Total | 9 / 11 Passed | |
- Commit
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- Reviewed
Table of Contents
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