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

With no annotations present, the description carries the full disclosure burden. It implies a pure, side-effect-free computation and discloses nothing about error behavior, matching constraints, or return format. For a stateless calculator the risk is low, but the disclosure is only minimally adequate.

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 core action, then parameters, then examples, then a usage line — tight and scannable. The closing 'Use whenever...' sentence is close to filler but does carry routing value.

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?

No output schema and no annotations, so the description is the only source of behavioral information. It never explains that `from`/`to` must belong to the declared `category`, what happens on a mismatched or unknown unit id, or what the call returns. That constraint is the main way an agent could call this tool incorrectly.

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 all four documented parameters are already explained in the schema; the description largely restates them and repeats the category enum. It omits the fifth parameter, `locale`, entirely. The conversion examples (km→mi, c→f, mb→gib) add modest value by showing unit-id format.

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 a numeric value between units') and immediately grounds it with category enumeration and concrete examples (km→mi, c→f, mb→gib). No sibling tool in the list competes with it, so an agent can identify it instantly.

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 whenever a user needs a unit conversion' gives a clear positive trigger condition. It offers no exclusions or alternatives, but none of the sibling utilities overlap with this capability, so there is little to disambiguate against.

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