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

Annotations already declare this a safe, idempotent, read-only, closed-world operation, so the safety profile is fully covered. The description adds only a light hint about returned fields (catalog id, active listing count); it says nothing about filtering behavior or result limits.

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?

A single front-loaded sentence with no wasted words; the primary input (model_id) and its alternative are stated up front. Slightly dense parenthetical, but efficient.

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 6-parameter, zero-coverage schema with no output schema, the description is only partially sufficient: it covers model identification but omits category and the year range filters, which an agent would have to infer from parameter names alone.

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% across 6 parameters, so the description carries the burden, but it only explains model_id sourcing and the brand+model alternative. The category enum and the year_min/year_max range filters are never mentioned, leaving half the inputs semantically undocumented.

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 ('List versions/trims for a model') and clarifies the useful return content (catalog id and active listing count). It is clearly distinguishable from the sibling list_models, which it explicitly references as the source of model_id.

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?

Gives actionable routing guidance: obtain model_id from list_models, or alternatively pass brand+model names. It does not state when not to use this tool or contrast it with other lookup siblings, but the invocation context is clear.

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