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

Annotations already declare readOnly, non-destructive, open-world behavior, so safety is covered. The description adds real value beyond them by describing the response shape — listing counts, typical prices, dial variants, references — which is important since there is no output schema. It says nothing about price freshness or behavior on ambiguous model names.

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?

One dense sentence that leads with what the tool returns and closes with the selection condition. No filler, no repetition of the title, and the most decision-relevant content is front-loaded.

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 one-parameter read-only lookup with no output schema, the description covers both the return contents and the usage trigger adequately. The only gap is what happens with an ambiguous or unmatched model name, which would matter in a catalog this large.

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?

Single `query` parameter with 100% schema description coverage, so the baseline is 3. The description's examples reinforce the schema's own example but add no new constraints such as accepted shorthand, fuzzy matching tolerance, or the 80-character limit's implications.

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 ("Shows one model") and enumerates exactly what comes back: current listing count with typical prices, available dials with prices, and references. The examples (Rolex Daytona, Patek Philippe Nautilus) and the emphasis on "one model" distinguish it from brand-level or single-watch siblings.

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 an explicit trigger: use when someone names a model and wants an overview before choosing a dial or reference. That also implies the hand-off point to dial/reference-level tools. It stops short of naming alternatives explicitly or stating when not to use it (e.g. an exact reference query).

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