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

Annotations already declare read-only, idempotent, open-world, non-destructive behavior, so the bar is lower, and the description adds genuinely useful detail: redirects are followed up to a limit of 5, and the output is graded n/6 with named header sources. It does not, however, mention rate limits, timeouts, or what happens to unreachable URLs.

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, front-loaded with the core action and redirect behavior, with no filler. The trailing reference links (MDN, OWASP) consume space but provide interpretability value for the header definitions.

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?

With no output schema, the description carries the burden of explaining returns and does so by naming the reported headers and the n/6 grade, so an agent knows what to expect. Missing only edge-case behavior (errors, timeouts, non-HTTP responses).

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 coverage is 100% and the single parameter's constraints (absolute http(s) URL, rejected private/loopback/cloud-metadata addresses, 2048 max length) are fully documented in the schema. The description adds nothing beyond that, so the baseline 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?

States a specific verb (fetch/scan) and resource (HTTP security headers) and enumerates exactly which six headers are inspected plus the n/6 grading output. This cleanly separates it from sibling scanners like check_ssl, check_cors and check_url_status.

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 description of what it does; there is no explicit when-to-use or when-not-to-use guidance, nor any pointer to sibling tools such as trace_redirects for redirect-chain work or check_ssl for TLS. Adequate but with a clear routing gap.

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