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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses the exact scanning behavior (one GET over https to the home page), the limitation that it only checks presence and values rather than quality, and the pricing model including that failed calls are not charged. These are meaningful behavioral details for an agent deciding whether to invoke a paid external check.

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 front-loaded with the tool's core action and scope, then follows with return information, limitation, and pricing. The listed headers are specific and useful rather than redundant, and every sentence contributes to correct invocation or interpretation.

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?

For a simple one-parameter read-only check with an output schema already present, the description provides enough context: it identifies the scanned page, the checked headers, the scoring approach, the limitation, and the cost model. An agent has what it needs to decide whether and how to call the tool.

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 only parameter is domain, and the schema already documents it as a required domain name example. The description adds no syntax, formatting, or validation detail beyond the schema, so with 100% schema coverage the baseline score of 3 is appropriate.

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 uses a specific verb and resource: it checks live HTTP response headers of a site's home page for seven named security headers. It also states the scope (one GET, https, home page) and return shape (present/missing headers plus a score out of 7), which clearly distinguishes it from narrower siblings such as csp_evaluator_audit or referrer_policy_audit.

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 gives clear context for what the tool does and notes an important limitation: it does not judge the quality of header values. However, it does not explicitly say when to use this instead of related siblings like csp_evaluator_audit, referrer_policy_audit, or cors_misconfig, so usage guidance is implied rather than fully specified.

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