convert_units

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

With no annotations provided, the description carries the full burden of disclosing behavior. It states the core action and supported units but does not mention return format, error handling for unsupported units, precision/rounding behavior, or any side effects. An agent knows what it converts but not what the response looks like or how failures are surfaced.

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 a single sentence followed by a structured list of categories and units. It is compact, scannable, and front-loaded with the primary action. Every part earns its place; the unit list is dense but necessary for correct invocation.

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 simple conversion tool, the description covers supported units and categories, which is the critical information for calling it correctly. It lacks an output schema and does not explain the return type, but the expected output is easily inferred as the converted number. The absence of edge-case details (e.g., temperature offset formulas) is a minor gap, not a blocker.

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 input schema describes 'from' and 'to' with only single examples (e.g., 'mi', 'kg'), leaving the full set of valid units implicit. The description compensates by exhaustively listing all supported units per category, giving the agent complete vocabulary for these parameters. This adds meaningful semantic value beyond the schema's terse examples.

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 opens with 'Convert a value between units,' a clear verb-resource pair that immediately identifies the tool's function. It then enumerates supported categories and their units, which unambiguously distinguishes it from the sibling tools (calculate, statistics, format_number, percentage_calc) that handle arithmetic rather than unit conversion.

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 implies when to use the tool—when a value needs converting between the listed unit categories. It does not explicitly name alternative tools or state when not to use it, but the context is clear enough given the distinct sibling set. There is no exclusions or 'use X instead' guidance, so it stops short of a 5.

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