Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds substantial behavioral nuance beyond the annotations: it explains that preflight OPTIONS requests are sent, what specific misconfigurations are detected, and critically clarifies the meaning of 'unknown' and 4xx responses. This is exactly the kind of context that helps an agent interpret results correctly.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is dense but every sentence earns its place: purpose, method, output format, and critical interpretation caveats are all included without redundancy. It is front-loaded with the core purpose and structured logically.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity, the description is complete: it covers what the tool does, how it works, what it returns, and how to interpret ambiguous or error-like results. The output schema exists, and the description complements it with risk-level and per-origin result context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already covers both parameters with 100% coverage, so the baseline is 3. The description does not add significant parameter-level detail beyond what the schema provides, though it does reinforce that multiple origins are tested by default.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's function: 'Test a URL for CORS misconfigurations' and enumerates specific detection categories. It is specific and actionable, but it does not explicitly differentiate itself from the sibling tool 'cors_checker', so it stops short of a 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context for when the tool is appropriate: testing URLs for CORS misconfiguration issues. It does not mention alternatives or exclusions, but the intended use case is unambiguous and well-scoped.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.