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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds genuine content-level context: gross '+X' pricing is included per paid option, and paid options are only surfaced on customer request — a non-obvious response-shaping rule.

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?

Purpose and scope are front-loaded in the first clause, and the pricing/paid-option rule is a compact second sentence. The main sentence is a dense run-on with heavy parenthetical enumeration, which costs a little readability but every clause carries distinct information.

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?

An output schema exists, so return formatting need not be explained, and all three parameters are optional, lowering the burden. The description adequately conveys the catalogue scope and pricing behaviour; the only real gap is sibling selection guidance.

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 coverage is 100%, so all three parameters are already documented, including locale/currency behaviour. The description restates the key effects ('frontlit patterns per shape', 'for a material, its size limits') but adds no syntax or format detail beyond the schema, so the 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 ('Lists the shapes... edges, tempering, LED lighting...') and enumerates exactly which option families are returned, which clearly separates it from list_materials and quote_mirror. An agent can route to it without opening the schema.

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 closing rule ('Paid options are only added when the customer asks') is a useful business constraint, but it governs the returned content rather than tool selection. There is no explicit statement of when to call this instead of list_materials or quote_mirror, so 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.