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

No annotations are provided, so the description must carry the full behavioral burden. It correctly implies a read-only check and usefully discloses cost ('1 credit per call'), but omits auth requirements, rate limits, and how redirects or non-HTTP URLs are handled. This is partial disclosure for a no-annotation tool.

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?

Two sentences with zero waste: the purpose is front-loaded and the cost is appended as a single concise clause. Every sentence earns its place.

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?

The tool is simple with one fully described parameter, and the description states what it checks and the cost. However, there is no output schema, and the description does not explain what a 'score' means or what the response contains, leaving a gap for the agent to understand the return value.

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?

Schema description coverage is 100%; the 'url' parameter is already documented as a 'Public http(s) page URL'. The description adds no additional syntax, examples, or constraints beyond what the schema provides, so the baseline of 3 applies.

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 states a specific verb ('Check') and resource ('HTTP security headers'), and names concrete headers (HSTS, CSP, X-Frame-Options). It does not explicitly differentiate from sibling tools like site_audit, but the narrow focus on security headers is clear.

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?

No explicit when-to-use or when-not-to-use guidance is given. However, the stated scope ('Check a site's HTTP security headers') implies usage for security header auditing. Alternatives such as site_audit are not mentioned, leaving the agent to infer this tool's specific niche.

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