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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds valuable context beyond that: it specifies that no paid entitlement is consumed and no raw provider records are exposed, which clarifies the side effects (none) and the scope of data. This aligns with the annotations and provides extra reassurance for an agent considering cost or data exposure.

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 a single sentence that front-loads the key differentiator ('FREE') and then states the purpose and constraints. Every word earns its place: 'FREE' signals cost, 'fixed' implies determinism, 'schema/capability preview' explains output, and the no-raw-records clause sets expectations. No fluff or repetition.

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 no parameters, no output schema, and annotations covering safety, the description covers the essentials: what it returns (a fixed preview), that it's free, and that it doesn't expose raw data. It could be slightly more explicit about the intended use case (e.g., 'Use this to understand the structure of Horse Truth data before purchasing'), but the current wording is sufficient for an agent to decide to call it for a preview.

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 the schema is trivially covered. The description does not need to explain parameters since there are none. The baseline for 0 params is 4, and the description adds no parameter-related details (which is appropriate). No gaps exist here.

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 clearly states a specific verb ('Return') and a specific resource ('fixed Horse Truth schema/capability preview') with context ('for Chance With Wolves'). It also distinguishes itself from sibling tools (like horse_rankings or resolve_horse) by being a preview rather than data retrieval or analysis. The phrase 'no raw provider records are exposed' further clarifies its non-data nature.

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 implies usage: it's free and doesn't consume paid entitlement, so it's presumably for previewing capabilities without purchasing. However, it does not explicitly state when to use this tool versus siblings, nor does it mention any alternative. The 'FREE' hint suggests a trial/preview context but leaves the 'when not to use' implicit.

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