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

Beyond the readOnly/openWorld/idempotent annotations, the description discloses pricing, the x402 payment flow and retry mechanism, passivity, expected runtime, and what is returned. These are exactly the behavioral details an agent needs before invoking a paid remote check.

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 dense but every clause earns its place: cost/payment mechanics, scope, checks performed, return value, and runtime. It is front-loaded with the critical payment condition and remains compact.

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 does well by stating that the tool returns a grade A+..F and fixes, and by listing the checks behind that grade. It does not describe the response shape in more detail, but it is sufficiently complete for correct selection and invocation.

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 single url parameter is fully documented in the schema, including the public http(s) URL or bare-domain format. The description reinforces the 'public website' scope but adds no further parameter semantics beyond the schema.

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 states a specific verb and resource: a passive check of a public website's HTTPS setup, with an explicit list of what is examined and a grade returned. It is clear what the tool does, though it does not explicitly name or distinguish itself from sibling tools such as security_scan_lite.

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?

The word 'passive' and the HTTPS/security-header focus imply when the tool is appropriate, but there is no explicit when-to-use guidance or named alternative for broader active scans. An agent can infer usage, but sibling selection remains ambiguous.

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