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

With no annotations, the description carries the burden and does disclose the key behavior: it makes a fetch, produces a 0–100 score, letter grade, and per-header recommendations, and states the cost (x402 $0.02/call, USDC). It does not mention timeout/redirect handling, but for a read-only fetch tool this is solid disclosure.

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?

Front-loaded with the action, then return values, usage, and pricing. Slightly redundant ('grade its HTTP security headers' is repeated in the usage sentence) but no padding.

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?

There is no output schema, so the description usefully explains the return shape (score, grade, per-missing-header recommendations). With one fully-schema-documented param and no annotations, the definition is nearly complete, though secondary execution details (redirects, timeouts) are unaddressed.

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% for the single 'url' parameter, so the schema already documents it. The description only says 'Fetch a URL' and adds no format or edge-case meaning (e.g. whether a bare domain vs full URL is accepted) beyond the schema's 'URL or domain'.

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?

States a specific verb+resource ('Fetch a URL and grade its HTTP security headers') and enumerates the exact headers covered (CSP, HSTS, X-Frame-Options, etc.), which separates it from the SSL-focused siblings like security_ssl_inspector and security_ssl_expiry.

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?

'Use this when an agent needs to grade a site's HTTP security headers + fix hints' gives a clear use context, but it largely restates the purpose and names no alternatives or exclusions (e.g. no guidance on when to prefer security_ssl_inspector or dev_page_verify).

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