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

Annotations already cover readOnly/openWorld safety, so the description's added value is the return shape (normalized cards with title, price/currency, seller type/country, badge, image, url) and the sort default. It omits pagination behavior despite Page/PageSize existing, which is a real gap for a list tool.

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?

Front-loaded with the primary capability, then constraints, then sort, then filters. Dense but each sentence carries information; the long filter enumeration is the only slightly bulky element, and nothing 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?

For a 15-param search tool with an output schema, the description covers modes, constraints, sorting, filtering sources and result shape well. The missing pagination semantics (Page/PageSize) is the only meaningful gap an agent would need.

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?

With 0% schema description coverage across 15 params, the description carries the full burden and mostly succeeds: it documents query/brand/model semantics, all sort enum values and the default, and names all nine optional facet filters with their source. It does not explain Page/PageSize, leaving two params 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 (search/browse) plus resource (Chrono24 luxury-watch listings) and clearly distinguishes the two modes (free-text keyword vs. brand/model browse). It also names the sibling tools it feeds into and draws from (chrono24_listing, chrono24_models, chrono24_facets).

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?

Explicitly states the selection rule 'at least one of query or brand is required', how model narrows within brand, where accepted filter values come from (chrono24_facets), and that the listing url is meant to be passed to chrono24_listing. Routing to alternatives is clear.

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