SmartTools

BMI calculator

bmi_calculator

Body Mass Index and category. system=metric: weight_kg, height_cm. system=imperial: weight_lb, height_ft (+height_in). Runs on smart-tools.xyz.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "bmi_calculator"
  }
}

Input Schema

Name	Required	Description
`locale`	No	Language for the source_url link (default en)
`system`	No	Unit system (default metric)
`height_cm`	No	Height in cm (metric)
`height_ft`	No	Height feet part (imperial)
`height_in`	No	Height inches part (imperial, default 0)
`weight_kg`	No	Weight in kg (metric)
`weight_lb`	No	Weight in lb (imperial)

Schema Changelog

Changes observed during successful MCP inspections.

First observedAug 17, 2026

TDQS

B3/5.0

Behavior2/5

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

No annotations are provided, so the description must carry the burden of behavioral disclosure. It only explains which parameters correspond to metric vs imperial systems and notes that it runs on smart-tools.xyz, but doesn't address safety, error handling, return format, or any side effects. For a simple read-only calculator, this is minimal.

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?

The description is concise at three short sentences and front-loaded with purpose. However, 'Runs on smart-tools.xyz' is extraneous and adds no behavioral or usage value.

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

Completeness2/5

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

The description explains input grouping but omits details about the output (beyond 'category'), whether any parameters are required per system, and how invalid inputs are handled. With no output schema and no annotations, this leaves significant gaps for the agent.

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

Parameters4/5

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

The description adds value by grouping parameters into metric (weight_kg, height_cm) and imperial (weight_lb, height_ft, height_in) systems, an important distinction not obvious from the flat schema. This complements the 100% schema coverage and helps the agent select the correct parameter set.

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

Purpose4/5

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

The description states 'Body Mass Index and category', clearly identifying the tool's function as calculating BMI and its category. It distinguishes from sibling calculators like BMR or body fat by topic, though it lacks an explicit verb like 'calculate'.

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

Usage Guidelines2/5

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

No guidance is provided on when to use this tool versus alternatives like bmr_calculator or body_fat_calculator. The description only mentions unit systems and parameter groupings, not selection criteria or exclusions.

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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