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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The description only mentions 'number discarded', but the schema reveals many parameters are 'discarded after' various checks. It does not explain what the tool actually does with the inputs, what side effects (if any) exist, or what happens to the inputs. The description is misleading about the tool's behavior, contradicting the schema's indication of a multi-purpose validation tool. This is a significant 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?

The description is extremely short, but that is not conciseness; it is under-specification. It lacks the necessary detail to be useful. There is no front-loading of key purpose, and the single sentence is misleading. A 2 is appropriate because it is brief but fails to convey any meaningful 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?

Given the tool's complexity (10 parameters, no output schema, no annotations), the description is completely inadequate. It does not explain what the tool does, what the inputs are used for, or what the output is. The schema provides parameter details but no overall context. An agent cannot reliably use this tool based on this description.

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 description coverage is 100%, so the schema documents each parameter. However, the description does not add any meaning beyond the schema; it actually misdirects. The description's reference to 'nanometers to meters' is unrelated to the parameters. The schema itself provides some per-parameter descriptions, but the tool's purpose is unclear, and the description fails to tie parameters together. With 10 parameters, the description should explain how they relate, but it does not.

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 'Nanometers to meters, number discarded' is misleading and does not match the actual tool behavior. The name 'nm-m' suggests a unit conversion, and the description reinforces that, but the input schema shows a collection of unrelated parameters (ref, url, city, feed, etc.) with no relation to nanometers or meters. The description is vague and fails to state what the tool actually does with these parameters, which appear to be discarded after some checks. It does not distinguish from siblings at all.

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?

There is no guidance whatsoever on when to use this tool versus alternatives. The description gives no context about the intended use case, no conditions for invocation, and no mention of related tools. The parameter list is a grab-bag of different data types, making it impossible for an agent to infer when this tool is appropriate.

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