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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds only "Returns equivalent size," which is redundant with the output schema and adds no behavioral context such as rounding precision or supported direction of conversion.

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?

The core purpose is front-loaded in one efficient sentence, but the trailing "See list_bundles for related 'textile-mode' calculators" is irrelevant to a ring-size tool and consumes space without earning it.

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-format explanation is not required. Still, the phantom "to-system" parameter and the unmentioned FR enum value leave the agent with an inaccurate model of the inputs, which is a real gap for a two-parameter tool.

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%, but the description actively misleads: it lists "to-system" as an input even though the schema has only size and from_system, and it names EU/US/UK/Japan while the enum also includes FR. This introduces parameter confusion rather than adding meaning.

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 — convert ring sizes between EU/US/UK/Japan systems — so the purpose is immediately clear. However, it fails to differentiate from the obvious sibling calculate_ring_size (basic sizing) or calculate_clothing_size_convert; the only cross-reference given is an unrelated pointer to list_bundles.

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?

"Use for international jewelry shopping" gives one concrete usage context, which is better than nothing. There are no exclusions or named alternatives, so an agent cannot tell why it should pick this over calculate_ring_size or calculate_bra_size_convert.

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