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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. Beyond that the description adds two useful behavioral facts: it reports the 'final' status code (implying redirects are followed) and it returns a verdict per header rather than raw values. Missing are any notes on auth, rate limits, or what happens when the URL is unreachable.

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?

One dense sentence that front-loads the return value (status code plus headers) and lists the concrete header names that matter. The trailing 'and others' is slightly vague but keeps the sentence short rather than enumerating everything.

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 one-parameter read-only tool with full annotation coverage and no output schema, the description does the important work of explaining what is returned, which the absent output schema would otherwise have to supply. Only cross-tool routing is missing.

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?

There is a single parameter with 100% schema description coverage, including the 'https:// is assumed' convenience, so the schema carries the semantics. The description adds no meaning about the url argument beyond what the schema already states, making the baseline 3 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 names a specific verb and resource ('Returns the final status code and the response headers') and scopes it to search/security headers, so the agent knows exactly what comes back. It does not name any sibling, so the boundary with trace_redirects or check_page_seo is left to inference.

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?

Usage is only implied by the phrase 'headers that matter for search and security', which hints at the diagnostic scenario but never states when to pick this over trace_redirects or check_page_seo. No exclusions or prerequisites are given.

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