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

Despite annotations already covering read-only, idempotent, and non-open-world behavior, the description adds substantial context: no provider/browser call or scan allowance is consumed, missing/failed evidence remains unavailable rather than zero, aggregates use the existing permitted corpus, and quoted source text is untrusted. These are meaningful operational and security semantics beyond structured annotations.

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 compact and mostly front-loaded with the key limitation about cached/saved data. The opening sentence 'Measured category benchmark' largely repeats the title, but the remaining sentences are dense with useful constraints and 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 zero-parameter, read-only tool with annotations covering safety, the description supplies the important operational constraints and data trust note. It does not describe the shape or content of the returned benchmark, but given the absence of an output schema and the tool's simplicity, the definition remains largely complete.

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 tool has zero parameters, so there is nothing for the description to clarify about parameter meaning. The schema is empty and fully consistent with the tool taking no inputs, making the baseline score of 4 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?

The description states a specific action ('reads saved measurements or existing caches') and resource ('measured category benchmark'), so the agent knows it retrieves benchmark data rather than performing a scan. It does not differentiate from siblings such as get_visibility or get_share_of_voice, but the core purpose is clear.

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 implies usage by saying it reads saved measurements or existing caches only and consumes no scan allowance, which suggests when not to use a rescan tool. However, it never explicitly states when to choose this tool over alternatives like request_rescan or other visibility tools, leaving selection guidance implied rather than explicit.

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