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

Annotations cover the safety profile (readOnlyHint, openWorldHint), and the description adds genuinely new behavioral context: the call is free and results are cached up to 5 minutes, so the agent knows the answer may be stale. It doesn't disclose rate limits or whether sampling a service incurs any cost later.

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 short sentences, front-loaded with the key fact ('Free.'), and every clause adds information: free, real answer, cache window, and preview purpose. Nothing is wasted.

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?

With no output schema, the description does tell the agent it will receive a real sample answer, which sets expectations for format preview. It remains incomplete on the service enum semantics and on whether the sample is a truncated or full response.

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 0% and the single 'service' parameter carries a six-value enum, yet the description only says 'from a Brük service' without explaining what pulse, payment-check, issuer-check, token-check, large-payments, or send-check mean. With zero schema documentation, the description fails to compensate for the coverage gap.

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: it returns a recent real answer from a Brük service as a free sample. That distinguishes it from the paid, service-specific siblings like send_check and token_check, though it never names those alternatives explicitly.

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?

The phrase 'so you can see the format before paying' implies the usage condition: preview the response shape before invoking a paid service. However, no alternatives are named, no when-not-to-use guidance is given, and nothing says whether multiple services can be sampled.

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