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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, not open-world), so the bar is lower. The description adds genuinely useful behavior: no authentication needed, the card is static for Tesla regardless of input, and the brand argument only produces a sign-in prompt. It stops short of describing the card's output structure in detail.

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?

Well front-loaded: the core action and the no-sign-in constraint come first, then the trigger, then the limitation. The final two sentences restate the example-brand constraint already implied earlier, costing a little redundancy.

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 no-parameter, read-only example tool with no output schema, the description covers what the agent needs: what is returned conceptually, that auth is not required, and that the input brand does not change the payload. Nothing essential is missing, though engine-level detail of the card is only summarized.

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 the single 'brand' parameter is already fully documented, including that it is optional and non-determinative. The description's note that the example brand is always shown echoes rather than extends the schema text, so the 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?

The description states a specific verb and resource ('Shows ... a real visibility card for one example brand (Tesla)') and enumerates exactly what the card contains: mention frequency per engine, named competitors, and sample answers. It also implicitly separates itself from the signed-in sibling get_visibility by emphasizing the no-login, example-brand scope.

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 an explicit trigger ('Use it when someone asks whether their brand shows up in AI answers and has not signed in') and states what to do instead for the signed-in case ('to check their own brand they sign in'). The when-to-use condition and the boundary against the real visibility tool are both spelled out.

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