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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is largely redundant here. The description nevertheless adds real value beyond annotations: exact definitional factors, 12-significant-digit precision, determinism, and concrete limits (64 KB input, 1 s per call, 1 MB result). Its only weakness is restating the side-effect-free profile already in annotations.

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?

Front-loaded with the verb, resource, units, and default behavior; the When/Not-for/Side-effects/Limits structure is scannable. The bilingual duplication roughly doubles the length, which is the main cost, though each individual sentence earns its place.

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 values need no explanation, and the description still covers precision, default expansion, limits, and exclusions. For a 3-parameter conversion tool this leaves nothing an agent needs missing.

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 baseline is 3; the description adds genuine meaning by explaining that omitting 'to' returns every unit, which the schema only hints at with 'omit for all'. It does not add unit-factor or accepted-alias detail beyond the schema, so not a 5.

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 (converts), resource (force), and the exact unit set (N, kN, lbf, kgf, dyn), and explicitly names the sibling it is not (convert-pressure). An agent can distinguish it from convert-mass/convert-torque/convert-pressure without opening any 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?

Has explicit 'When:' and 'Not for:' clauses with the alternative tool named (convert-pressure). The default behavior when 'to' is omitted is also described, so selection and invocation conditions are both covered.

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