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

readOnlyHint and openWorldHint already declare the safety/scope profile, so the description only needs to add context. It adds the breadth of data covered (all discounted weeks, availability, ten cheapest weeks, five biggest discounts, similar models), but nothing about auth, error behavior, or what happens with missing inputs — and much of the return content is already in the output schema.

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 sentences, front-loaded with what the tool returns and ending with the input instruction. The middle enumeration is dense but each item describes distinct returned data, so little 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 an output schema and annotations present, the main remaining need is input business rules. Both parameters are optional (0 required), yet the description never says what happens if neither is supplied, nor how conflicts between url and model are resolved — a real gap for a 2-param lookup.

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 coverage is 100% and both parameters carry their own examples, so the schema does the heavy lifting. The description adds one useful nuance — that you may pass either a model name or a page URL — but the schema already lists both fields and the description doesn't clarify precedence or whether exactly one is expected.

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+resource and scopes it as a single-model, in-depth lookup ('One yacht model in depth'), which implicitly separates it from list_yacht_models. It does not name that sibling or get_boat explicitly, so the distinction is inferable rather than stated.

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 when to use it by emphasizing depth for one model and giving example inputs, but it never says when NOT to use it or names the alternative (list_yacht_models for browsing, get_boat for a specific boat). Usage is left to inference.

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