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

No annotations are provided, so the description carries the full disclosure burden and largely drops it. It is silent on the fact that the result depends on material density via the 'stone' parameter (default moissanite), and says nothing about precision, rounding, or applicability limits of the round-brilliant assumption.

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?

Two terse fragments with zero padding and the key quantity front-loaded, which is efficient. However the brevity slides into under-specification rather than tightness — the cut assumption is stated while the material assumption, which matters more, is omitted.

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?

For a two-parameter conversion with no output schema and no annotations, the description should at minimum explain the material dependency and the nature of the returned value. Neither is present, leaving an agent able to call the tool but not to call it correctly for non-default stones.

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 only 50%: 'mm' is documented in the schema, but the 'stone' enum (moissanite/diamond/cz) has no description anywhere. The description's 'Round brilliant cut' hints at an assumption but does not explain that the stone choice materially changes the returned carat weight, so it fails to compensate for the coverage gap.

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 conversion (diameter in mm → carat weight) and pins the cut ('Round brilliant cut'), which implicitly distinguishes it from the reverse-direction sibling carat_to_mm. It never names that sibling, so it stops 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?

Contains no when-to-use guidance, no prerequisites, and no pointer to carat_to_mm for the inverse operation or to ring_size_convert for related sizing tasks. Usage has to be inferred entirely from the one-line purpose.

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