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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that lots are 'normalized', a modest data-shape note, but says nothing about pagination behavior or result volume beyond what the schema states.

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 filler; the resource and its two optional filters come first. It is tight, though slightly dense with two filters packed into one clause.

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 present and annotations covering the read-only/open-world profile, the description needn't explain return values. It communicates scope and filterability, which is sufficient for calling the tool correctly; only sibling routing is missing.

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 all five parameters are already documented in the schema, including the auction_id example and the department facet caveat. The description merely echoes that department and free-text filters exist, adding no syntax or semantics beyond the schema. Baseline 3 is appropriate.

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 ('lot listing') scoped to one auction with two filter modes, so the agent knows it is an auction-scoped listing rather than a cross-auction search. It does not explicitly name or contrast with siblings like bonhams_lot_search or bonhams_auction_detail, so it falls short of a 5.

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 phrase 'optionally filtered by department or a free-text query' implies how to narrow results, but there is no explicit when-to-use guidance, no when-not conditions, and no routing to the obvious sibling bonhams_lot_search for cross-auction lookups. Usage is only implied.

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