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

Annotations already declare it read-only, idempotent, non-destructive and open-world, so the safety burden is lifted. The description adds genuinely useful behavior not in the annotations: the two underlying sources (independent shops and eBay) and the fields each result carries, which substitutes for the missing 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 dense sentences, purpose front-loaded, no filler. The second sentence is long but earns its place by describing the result shape where no output schema exists.

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 13-parameter, no-required-params discovery tool with no output schema, the description covers both the source scope and the returned fields. Only the lack of guidance on result limits/pagination semantics (the limit param) keeps it from complete.

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 100%, so the schema already documents all 13 parameters with examples and enum values. The description restates facets (kind, original/print, price, size, colour) at a high level without adding syntax, defaults, or interaction rules beyond what the schema provides, so baseline 3 applies.

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 ('Find art for sale') and adds real scope: it searches independent artists' own shops plus eBay art. That clearly separates it from pricing/passport/royalty siblings, though no sibling is named explicitly.

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?

Usage is implied by the enumeration of search facets (subject, style, place, artist, kind, price, size, colour), so an agent can infer it is the discovery tool. However, there is no explicit when-to-use or when-not-to-use guidance, and no routing against check_art_listing, check_artworks_feed, or compare_where_to_sell.

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