Convert a numeric value between units. Categories: length, mass, volume, area, time, temperature, energy, speed, data, pressure. Accepts canonical names ('meter', 'pound') or common aliases ('m', 'lb'). Returns {input, output, category}.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | Target unit. | |
| from | Yes | Source unit, e.g. 'meter' or 'm'. | |
| value | Yes | Numeric value to convert. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden. It discloses the return format ({input, output, category}), that it accepts canonical names or aliases, and lists categories. This provides useful behavioral context, though it omits auth or rate limits.
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?
Three concise sentences with the action front-loaded. No redundancy, every sentence adds value. Ideal length for a conversion tool.
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?
The description explains the return format (no output schema), lists categories, and covers aliases. For a simple conversion tool with 3 required params, this is fairly complete. Lacks error handling details, but acceptable.
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 baseline is 3. The description adds context about accepted value formats and categories but does not add per-parameter details beyond what the schema already provides.
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 explicitly states 'Convert a numeric value between units,' specifies categories, and mentions accepted names and aliases. This clearly distinguishes it from sibling tools like convert_currency and convert_timezone, making the purpose very specific.
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 implicitly indicates when to use (for unit conversion) but does not explicitly state when not to use or point to alternative tools. Given the sibling context, an agent can infer, but the description lacks direct guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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Each tool has a distinct purpose: currency conversion, timezone conversion, unit conversion, date difference calculation, and listing supported entities. There is no overlap, so an agent can easily choose the correct tool.
Tools follow a consistent verb_noun pattern (e.g., convert_currency, list_timezones). The only minor deviation is 'date_diff' which uses noun_noun, but it is still clear and fits the pattern of other tools.
With 6 tools, the set is well-scoped for a unit and currency converter. It covers all necessary operations without being too sparse or overwhelming.
The tools provide full conversion capabilities (currency, timezone, unit), date difference calculation, and listing helpers for timezones and units. There are no obvious gaps for the server's stated purpose.