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

The annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=true, and idempotentHint=false. The description adds substantial behavioral context beyond that: the 6-hour stored-record reuse, fresh override, rate limits of 10 per minute and 3 concurrent scans, 60-second runtime, and the fact that timed-out scans still complete and are stored.

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 front-loaded with the core action and return record, then adds caching, rate-limit, and timeout details in a compact sequence. Every sentence contributes operational information needed to invoke the tool correctly.

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?

Given there is no output schema, the description compensates by naming the returned record components: score, its two parts, level, per-check status, evidence, and fingerprint. It also covers the non-obvious async timeout behavior and rate limits, making the definition complete for this tool.

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%, so both parameters are already documented in the schema. The description reinforces that target is a public domain and explains fresh in terms of the 6-hour cache, but it adds only limited meaning beyond the structured 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: scanning a public domain and returning the full scan record with named components. It clearly distinguishes the tool's output scope from narrower siblings like get_score or list_checks, but it does not explicitly name those alternatives.

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 explains important usage behavior such as the 6-hour cache and the fresh override, plus rate limits and timeout handling. However, it does not explicitly say when to use scan_site versus get_report, get_score, or list_checks, so tool 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.