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

Annotations already declare readOnly, idempotent, closed-world, non-destructive behavior, so the safety bar is low. The description still adds value by disclosing the response units (inches and millimetres) and the empty-argument enumeration behavior, which annotations do not convey. It does not describe the shape of a single-cut response versus the full list, a minor remaining gap.

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 short sentences with zero filler. The core purpose and vocabulary come first, and the fallback rule is placed where it is needed, after the definition of the resource.

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 single optional-string, read-only lookup with no output schema, the description covers purpose, units, accepted vocabulary, and default behavior. Nothing an agent needs in order to call it correctly is 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% and the schema already supplies examples like "brunoise" and "allumette", so baseline is 3. The description goes beyond it by making the parameter's optionality meaningful — omission triggers a full listing — which the schema does not state.

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?

The description names a specific resource (classic knife cut dimensions) and the exact fields returned (size and method, in inches and millimetres). It enumerates concrete example cuts and states the no-argument fallback behavior, so an agent can distinguish this lookup from any of the calculator/recipe siblings 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?

It explicitly states the conditional usage: supply a cut to get that cut, omit it to list every cut with its size. That resolves the only real invocation decision for a one-parameter tool. It stops short of naming alternatives or exclusions, but no sibling tool overlaps this scope.

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