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

The description discloses behavioral traits beyond the annotations: the cost (US$0.02 per call or 1 Horse Truth credit) and the fact that raw provider records are not exposed, implying the output is a derived summary. Annotations already indicate read-only and non-destructive, so the added context about output nature and payment is valuable. It does not describe the exact return format, but given the annotations cover safety, this is sufficient.

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 two short sentences with no wasted words, making it efficient. However, the payment information is front-loaded before the core purpose, which could be seen as slightly distracting from the primary function. Still, it remains concise and to the point, earning a high score.

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 tool with one parameter and no output schema, the description covers cost and output nature but omits parameter semantics and explicit usage guidance. It mentions that raw records are not exposed, which is helpful, but it does not specify the output format or how to structure the 'horse' parameter. Given the tool's simplicity, a bit more detail would round out the description, but it is not wholly inadequate.

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 schema defines a single required string parameter 'horse' with zero description coverage. The tool description does not clarify what constitutes 'horse' (e.g., an ID, name, or other identifier). With 0% schema description coverage, the description fails to compensate for this ambiguity, leaving an agent uncertain about the required input format.

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-resource pair: 'Return derived intelligence for one horse.' This clearly indicates the tool's function and scope. However, it does not explicitly distinguish it from sibling tools like horse_snapshot or horse_signal, relying on the term 'derived intelligence' to imply a departure from raw data without direct contrast.

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 description provides no guidance on when to use this tool versus alternatives. There is no mention of preferred contexts, exclusions, or comparison with sibling tools. The only additional information is the payment mechanism, which is not usage direction. An agent cannot determine when to choose this over horse_snapshot or horse_explanation.

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