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

Annotations already establish read-only, non-destructive, open-world behavior, so the description is free to add operational detail — and it does: delivered search excludes unknown shipping before pagination, market/language interaction is explained, and output is described as Brickfact comparison links. It stops short of describing pagination limits or result ordering behavior.

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?

Three dense sentences with no filler; the capability statement leads and the trickier price_basis and shipping caveats follow. Every clause conveys distinct information an agent could act on.

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 16 parameters, one required field and an output schema (so return shape needn't be explained), the description covers the filter families but not the operational controls. An agent still lacks guidance on pagination, sort semantics and price currency, which matters for a price-comparison search.

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 only 13% across 16 parameters, so the description must carry more weight than it does. It adds real meaning for price_basis, query, theme_ids, pieces, age and retirement filters, but leaves sort, page, limit, language, current_offers_only, retirement_year and the currency/units of min_price/max_price entirely unaddressed.

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?

Opens with a specific verb+resource ('Find sets') and enumerates the searchable facets (name/number, theme IDs, budget, pieces, age, retirement status), so an agent knows exactly what this tool retrieves. It does not, however, distinguish itself from siblings like render_sets or compare_sets, which also surface set data.

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?

Provides real conditional guidance for the price_basis switch ('use delivered for budgets including shipping; item preserves the original item-only search'), which is genuinely actionable. But there is no guidance on when to choose this tool over render_sets or get_set_details, and no mention of prerequisites beyond the market requirement carried in the schema.

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