# heart_rate_zones

Calculate target heart rate zones for exercise. Parameters: age — Age in years. resting_hr — Resting heart rate in bpm (default: 60).

Agent View of the PolicyLayer registry record for `heart_rate_zones`. HTML page: https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/heart-rate-zones

## Facts

- Tool: `heart_rate_zones`
- 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: 2 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `age` | integer | yes |  |
| `resting_hr` | integer | no |  |

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": "heart_rate_zones",
    "arguments": {
      "age": 0
    }
  }
}
```

## Why heart_rate_zones is rated Low

This is a read-only calculation tool that retrieves derived information (heart rate zones) based on input parameters. It has no side effects, does not modify persistent data, does not execute arbitrary code or commands, does not delete anything, and does not involve financial operations.

From the tool's own definition: "The tool 'heart_rate_zones' calculates target heart rate zones based on provided age and resting heart rate parameters. The description contains no verbs indicating data modification, deletion, code execution, or financial transactions."

## Use case

AI agents call heart_rate_zones 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": {
    "heart_rate_zones": {}
  }
}
```

## 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_bmi` — Read — https://policylayer.com/tools/com-gadgethumans-swarm-x402-middleware/calculate-bmi.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
- …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