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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety and coverage profile is largely covered. The description adds a genuinely useful trait beyond them -- that the index spans historical auctions and includes sold/prices-realized lots -- but says nothing about pagination limits, result volume, or how sold vs live lots are returned.

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 dense sentence that front-loads the resource and its coverage before listing the filters. No filler, though cramming scope plus three filter dimensions into one clause makes it slightly harder to scan than two shorter sentences would.

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 100% parameter coverage, the remaining burden is disambiguation and result-shape context. The description covers the index scope but leaves the relationship to bonhams_auction_search / bonhams_auction_lots / bonhams_lot_detail for the agent to guess from sibling names.

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% and all 8 parameters are individually documented, so the baseline is 3. The description only restates the filter dimensions (department, country, free-text query) at a coarser level than the schema already does, adding no new syntax or format detail.

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 ('Bonhams lot search') plus the scope ('across every auction, current and historical -- including sold/prices-realized lots'). This distinguishes it in substance from the auction-level siblings (bonhams_auction_search, bonhams_auction_lots), though it never names them outright.

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 stated scope: use it to find lots across all auctions, including historical sold results, when filtering by department, country or free text. There is no explicit when-not-to-use or a named alternative such as bonhams_lot_detail for a single lot, so an agent must infer the boundary itself.

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