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

With no annotations, the description carries the full burden. 'Verify whether' implies a non-destructive read, which is the key safety signal, but the description says nothing about redirect handling, timeouts, or what a negative result looks like. Adequate for a simple read-only probe, but not rich behavioral context.

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?

A single sentence with no filler, and the resource being verified is front-loaded after the verb. Every word earns its place.

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 check with no output schema, the description should ideally say what the result conveys (e.g., presence plus parsed contacts, or failure modes). It gestures at this with 'with responsible vulnerability disclosure contacts' but leaves the return shape and no-file case unstated.

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 only one parameter and schema coverage is 100%, so the schema already fully documents 'domain' with an example. The description adds nothing beyond confirming that the domain is the target of the check, which is the expected baseline.

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 gives a specific verb ('Verify whether') and a precise resource ('an RFC 9116 security.txt file with responsible vulnerability disclosure contacts'), which is far more informative than the tool name alone. It implicitly distinguishes itself from the sibling scan_url_security_headers by targeting a specific well-known file rather than HTTP headers, though it never names that sibling explicitly.

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?

There is no when-to-use guidance, no mention of the alternative tool (scan_url_security_headers), and no conditions under which this check is or isn't appropriate. The intended use is only implied by the resource being checked.

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

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

No annotations are provided, so the description carries the full behavioral burden. It implies a read-only external network fetch and describes the computed result, but says nothing about rate limits, timeouts, redirect handling, whether the target must be publicly reachable, or what happens on an unreachable/invalid URL. For a tool that performs live outbound requests, this is a notable gap.

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?

A single sentence that front-loads the verb and resource, then specifies scope and output. Every clause earns its place with no filler.

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 scan tool with no output schema, the description covers the input type, what is checked, and the shape of the result (a letter grade). It is close to complete, though it omits failure behavior and whether results are structured or prose.

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% and the single 'url' parameter is documented in the schema with an example format, so the description need not restate it. The description adds no extra syntax or normalization details (e.g., whether a bare domain is accepted) beyond what the schema already provides, so the baseline of 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 (Scan), an explicit resource (HTTP/HTTPS URL), the exact scope of the check (7 critical OWASP security headers with named examples), and the output (a grade from A+ to F). An agent can immediately tell this apart from the sibling check_rfc9116_security_txt, which audits a file rather than live response headers.

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 implied by the wording ('Scan an HTTP/HTTPS URL for...'), so an agent can infer it is for auditing a site's header posture, but there is no explicit when-to-use, when-not-to-use, or reference to the sibling tool. The alternative (security.txt checking) is never mentioned, leaving routing to inference.

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