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convert_unit_convert

Unit Converter — Convert between units of measurement: length, weight, temperature, volume, area, speed, time, and data sizes. [category: convert]

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
toYesThe unit you want. It must belong to the same kind of measurement as the one you have.
fromYesThe unit you have. It must belong to the kind of measurement chosen above. Data sizes are the computing kind (1 kilobyte = 1024 bytes).
valueYesThe amount to convert. Negative numbers are fine (below-zero temperatures, drops in weight).
categoryYesWhat kind of measurement this is. Pick this first — it decides which units are available.length

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changed
    • changedInput schema / properties / value / description
      Previous value: -"JSON number, not a string. Negatives are valid (temperatures, deltas)."New value: +"The amount to convert. Negative numbers are fine (below-zero temperatures, drops in weight)."
  2. Changed7 schema fields changed
    • addedInput schema / properties / category / default
      Added value: +"length"
    • changedInput schema / properties / category / description
      Previous value: -"One of: length, weight, area, volume, speed, time, data, temperature. Anything else = 400."New value: +"What kind of measurement this is. Pick this first — it decides which units are available."
    • addedInput schema / properties / category / enum
      Added value: +[
+  "length",
+  "weight",
+  "area",
+  "volume",
+  "speed",
+  "time",
+  "data",
+  "temperature"
+]
    • changedInput schema / properties / from / description
      Previous value: -"Full snake_case name ('kilometer', 'mile_per_hour'), not symbols. Temperature units aren't validated — a typo returns garbage."New value: +"The unit you have. It must belong to the kind of measurement chosen above. Data sizes are the computing kind (1 kilobyte = 1024 bytes)."
    • addedInput schema / properties / from / enum
      Added value: +[
+  "meter",
+  "kilometer",
+  "centimeter",
+  "millimeter",
+  "mile",
+  "yard",
+  "foot",
+  "inch",
+  "nautical_mile",
+  "kilogram",
+  "gram",
+  "milligram",
+  "pound",
+  "ounce",
+  "ton",
+  "stone",
+  "square_meter",
+  "square_kilometer",
+  "square_centimeter",
+  "square_mile",
+  "square_yard",
+  "square_foot",
+  "square_inch",
+  "hectare",
+  "acre",
+  "liter",
+  "milliliter",
+  "cubic_meter",
+  "cubic_centimeter",
+  "gallon_us",
+  "gallon_uk",
+  "quart",
+  "pint",
+  "cup",
+  "fluid_ounce",
+  "tablespoon",
+  "teaspoon",
+  "meter_per_second",
+  "kilometer_per_hour",
+  "mile_per_hour",
+  "knot",
+  "foot_per_second",
+  "second",
+  "millisecond",
+  "minute",
+  "hour",
+  "day",
+  "week",
+  "month",
+  "year",
+  "byte",
+  "kilobyte",
+  "megabyte",
+  "gigabyte",
+  "terabyte",
+  "bit",
+  "kilobit",
+  "megabit",
+  "gigabit",
+  "celsius",
+  "fahrenheit",
+  "kelvin"
+]
    • changedInput schema / properties / to / description
      Previous value: -"Same rules as 'from', same category. Data units are binary (kilobyte = 1024 B); temperature accepts only celsius/fahrenheit/kelvin."New value: +"The unit you want. It must belong to the same kind of measurement as the one you have."
    • addedInput schema / properties / to / enum
      Added value: +[
+  "meter",
+  "kilometer",
+  "centimeter",
+  "millimeter",
+  "mile",
+  "yard",
+  "foot",
+  "inch",
+  "nautical_mile",
+  "kilogram",
+  "gram",
+  "milligram",
+  "pound",
+  "ounce",
+  "ton",
+  "stone",
+  "square_meter",
+  "square_kilometer",
+  "square_centimeter",
+  "square_mile",
+  "square_yard",
+  "square_foot",
+  "square_inch",
+  "hectare",
+  "acre",
+  "liter",
+  "milliliter",
+  "cubic_meter",
+  "cubic_centimeter",
+  "gallon_us",
+  "gallon_uk",
+  "quart",
+  "pint",
+  "cup",
+  "fluid_ounce",
+  "tablespoon",
+  "teaspoon",
+  "meter_per_second",
+  "kilometer_per_hour",
+  "mile_per_hour",
+  "knot",
+  "foot_per_second",
+  "second",
+  "millisecond",
+  "minute",
+  "hour",
+  "day",
+  "week",
+  "month",
+  "year",
+  "byte",
+  "kilobyte",
+  "megabyte",
+  "gigabyte",
+  "terabyte",
+  "bit",
+  "kilobit",
+  "megabit",
+  "gigabit",
+  "celsius",
+  "fahrenheit",
+  "kelvin"
+]
  3. First observed

TDQS

A3.5/5.0
Behavior2/5

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

The description adds no behavioral information beyond the schema's own category list. Annotation readOnlyHint=false is questionable for what is conceptually a pure computation with no side effects, and the description does nothing to clarify that no state is mutated. With annotations present the bar is lower, but zero behavioral content is still a real gap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

One front-loaded sentence with the tool name followed by the concrete action and scope — efficient and easy to scan. The trailing '[category: convert]' tag is internal metadata noise that earns no place in the description.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 4-parameter, all-required, enum-driven computation tool with no output schema and full schema coverage, the description is sufficient to call it correctly. It is only slightly thin on the edge cases (invalid cross-category pairs, negative values) that the schema partially handles.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% (including the 'pick this first' guidance on category and the 1024-byte note on data sizes), so the schema carries all parameter meaning. The description only restates the category domains and adds no syntax, format, or constraint detail beyond it; baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Convert between units of measurement') and enumerates the eight supported measurement domains, which cleanly separates it from the file-oriented convert_* siblings (convert_file, convert_data, convert_document). An agent can tell at a glance this is a unit-math tool, not a file format converter.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the purpose — the tool is self-evidently for unit conversion — but there is no explicit when-to-use, when-not-to-use, or pointer to alternatives among the many convert_* siblings. The guidance is adequate only because the domain is so narrow that inference is easy.

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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