# calculate_bmi

Calculate BMI (Body Mass Index) from weight and height. Parameters: weight — Weight (kg for metric, lbs for imperial). height — Height (cm for metric, inches for imperial). unit — 'metric' (default) or 'imperial'.

Agent View of the PolicyLayer registry record for `calculate_bmi`. HTML page: https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/calculate-bmi

## Facts

- Tool: `calculate_bmi`
- Server: X402 Middleware (`@gadgethumans/x402`) — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware.md
- Install: `npx -y @gadgethumans/x402`
- Homepage: https://github.com/scotia1973-bot/gadgethumans-x402
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server rate-limited: no
- Parameters: 3 (2 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `unit` | string | no |  |
| `height` | number | yes |  |
| `weight` | number | yes |  |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "calculate_bmi",
    "arguments": {
      "height": 0,
      "weight": 0
    }
  }
}
```

## Why calculate_bmi is rated Low

This tool performs a purely computational calculation on provided input parameters and returns a result. It has no side effects, does not modify any data, does not execute external code or commands, does not delete or overwrite information, and does not involve financial transactions.

From the tool's own definition: "Tool name 'calculate_bmi' and description indicate it 'Calculate[s] BMI (Body Mass Index) from weight and height' with parameters for weight, height, and unit. No modification, deletion, execution, or financial transaction occurs."

## Use case

AI agents call calculate_bmi to retrieve information from X402 Middleware without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches X402 Middleware:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "calculate_bmi": {}
  }
}
```

## Other tools on X402 Middleware (57)

- `agent_memory` — Destructive — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/agent-memory.md
- `wallet_buy` — Financial — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/wallet-buy.md
- `x402_payment_request` — Financial — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/x402-payment-request.md
- `x402_pricing` — Financial — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/x402-pricing.md
- `x402_verify_payment` — Financial — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/x402-verify-payment.md
- `analyze_readability` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/analyze-readability.md
- `analyze_url` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/analyze-url.md
- `bmr_calc` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/bmr-calc.md
- `calculate_date` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/calculate-date.md
- `check_ssl_certificate` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/check-ssl-certificate.md
- `classify` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/classify.md
- `compare_items` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/compare-items.md
- `convert_currency` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/convert-currency.md
- `convert_timestamp` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/convert-timestamp.md
- `convert_timezone` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/convert-timezone.md
- `decode_jwt` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/decode-jwt.md
- `detect_language` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/detect-language.md
- `dns_lookup` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/dns-lookup.md
- `extract_contacts` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/extract-contacts.md
- `generate_seo_metadata` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/generate-seo-metadata.md
- `generate_uuid` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/generate-uuid.md
- `geocode` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/geocode.md
- `geolocate_ip` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/geolocate-ip.md
- `get_air_quality` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/get-air-quality.md
- `get_crypto_prices` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/get-crypto-prices.md
- `get_forecast` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/get-forecast.md
- `get_og_metadata` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/get-og-metadata.md
- `get_weather` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/get-weather.md
- `grammar` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/grammar.md
- `hash_text` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/hash-text.md
- …and 27 more: https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=com-gadgethumans-swarm-x402-middleware · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/com-gadgethumans-swarm-x402-middleware