convert_unit

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

With no annotations, the description carries the behavioral disclosure burden. It does reveal that the tool only works with listed units and that parameters must follow an 'either conversion_id OR from_unit+to_unit' pattern. However, it does not mention error handling, side effects (it is likely read-only, but not stated), or what happens if both modes are supplied. For a simple pure function, this is adequate but not rich.

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 concise: three short sentences in a clever 'When:/Params:/Example:' structure. Every sentence carries essential information, with no filler or repetition. It is perfectly front-loaded with the usage condition.

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 simplicity and the presence of an output schema, the description is largely complete. It covers when to use, how to specify parameters, and gives an example. It also points to list_unit_conversions for additional context. It does not discuss edge cases or error conditions, but those are not critical for such a straightforward conversion tool.

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?

The schema has 0% description coverage, so the description must compensate. It explains the parameter relationship: 'value; either conversion_id OR from_unit+to_unit' — a crucial semantic not present in the schema. The example 'value=1, conversion_id="mile_to_km"' concretely demonstrates usage. This adds meaningful value beyond the bare schema definition.

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 clearly states the tool's function: 'convert between listed measurement units' — a specific verb and resource. It also explicitly excludes free-form dimensional analysis, distinguishing it from more general calculation tools. This is unambiguous and differentiates from siblings like evaluate or base_convert.

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?

The description opens with 'When: convert between listed measurement units (not free-form dimensional analysis)', providing an explicit condition for use. It also gives a direct alternative: 'Call list_unit_conversions first if unsure', which is a clear fallback. This fully satisfies the when/when-not/alternatives criterion.

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