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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds value by specifying the return structure (per-header findings, fix advice, score, grade), which is not covered by annotations or a schema. There is no contradiction and the description is consistent with the read-only, idempotent nature.

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 two sentences with no redundancy. The first sentence immediately states the action, scope, and output; the second gives usage guidance and differentiates from a sibling. Every word earns its place, and key information is front-loaded.

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 single-parameter, read-only audit tool with no output schema, the description is complete. It explains what the tool does, what it returns (findings, advice, score, grade), and when to use it. There are no prerequisites or caveats that an agent would need to know. The lack of output schema is compensated by the description's mention of the output structure.

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 schema description covers the url parameter fully (100% coverage), explaining it is the URL to audit for security headers. The tool description repeats the same header list but adds no new meaning or format guidance. Since schema already does the heavy lifting, the baseline 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 clearly states it audits HTTP security headers of a single URL, enumerates the header categories (CSP, HSTS, X-Frame-Options, etc.), and specifies the output: per-header findings with fix advice, a score, and a letter grade. This distinguishes it from the sibling security_scan by explicitly noting the scope difference, making the tool's purpose unambiguous.

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?

It provides explicit guidance: 'Use it when you need header hardening advice' and contrasts it with security_scan, which combines this audit with URL reputation and subdomain discovery. This tells the agent exactly when to choose this tool over an alternative.

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