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

Annotations only say it's a non-read-only, non-idempotent, open-world call; the description adds the material facts an agent needs: it burns the API key owner's plan quota, it makes live outbound requests impersonating six crawlers, and it is asynchronous (returns scan_id rather than results). That is real disclosure beyond the structured fields.

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, both load-bearing: the first front-loads the action and its scope, the second handles return value, cost, and the next call. No filler or restatement of the title.

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 an async kick-off tool with no output schema, the description supplies the missing return contract (scan_id) and the follow-up call, plus the quota side effect. Nothing an agent needs in order to invoke it correctly is absent.

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 url parameter is already documented with a format example. The description adds only indirect semantics — 'each page is requested separately' hints the input is a site root whose pages get enumerated — so it neither compensates for nor extends the schema meaningfully. Baseline 3 is appropriate.

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 and resource ('Start a full scan of a website') and then spells out what the scan actually does — multi-bot fetches, rendered comparison, six SEO/AEO/GEO categories, Domain Rating. That level of specificity clearly separates it from get_scan (retrieval) and list_scans (enumeration).

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?

Explicitly defines the workflow: 'Returns a scan_id; then call get_scan with wait_seconds' — an agent knows this is the entry point and what to call next. It also signals cost via 'Uses the API key owner's plan quota', though it doesn't state when NOT to scan (e.g. dedupe against an existing in-flight scan) or any rate limit.

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