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

With annotations present but minimal (readOnlyHint=false, idempotentHint=false, destructiveHint=false), the description adds real behavioral context: the scan is anonymous, fetches only headers and HTML, and uses no real browser, so the agent knows it is a lightweight, non-mutating probe. It also discloses the output shape (preScanId plus report link), though it omits timing, rate limits, or auth requirements.

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 core capability and return value are front-loaded in the first sentence, which is exactly right. The trailing sentences about CookieInspector's positioning and the legal disclaimer are marginally useful but dilute a definition that could be tighter.

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 single-parameter tool with no output schema, the description covers what it does, what it returns, and where to go next, which is sufficient to invoke it correctly. It stops short of explaining expected latency or failure modes, but nothing essential to calling the tool 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?

Only one parameter and schema coverage is 100%, so the schema already documents the url format with an example. The description adds scope meaning (it targets the home page, not arbitrary subpages) but nothing about URL normalization or accepted schemes beyond the schema's example.

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 concrete verb and resource ('Start a quick, anonymous pre-scan of a public website's home page') and scopes it precisely ('HTTP headers and HTML only, no real browser'). This clearly distinguishes it from the sibling start_scan, which implies a full browser-based scan.

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?

It gives follow-up routing by naming get_prescan_result and the preScanId handoff, which is useful workflow guidance. However, it never states when to choose this over start_scan, nor any precondition such as the site needing to be public and reachable, so selection guidance is only implied.

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