# jwt_decoder

Decode a JSON Web Token's header and payload (base64url). Does NOT verify the signature — that needs the secret/key. Runs on smart-tools.xyz.

Agent View of the PolicyLayer registry record for `jwt_decoder`. HTML page: https://policylayer.com/tools/io-github-9thshini-smart-tools/jwt-decoder

## Facts

- Tool: `jwt_decoder`
- Server: SmartTools (`https://smart-tools.xyz/mcp`) — https://policylayer.com/tools/io-github-9thshini-smart-tools.md
- Homepage: https://github.com/https://smart-tools.xyz/mcp
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server CORS policy: *
- Server rate-limited: no
- Parameters: 2 (1 required)
- Recommended policy verdict: Rate-limited

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `token` | string | yes | The JWT (header.payload.signature) |
| `locale` | string | no | Language for the source_url link (default en) |

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": "jwt_decoder",
    "arguments": {
      "token": "<token>"
    }
  }
}
```

## Why jwt_decoder is rated High

jwt_decoder triggers real processes with real consequences. An agent gone sideways doesn't fire it once. It starts dozens of builds, sends mass notifications, or burns through compute before anyone looks up.

Risk signals: Handles credentials or secrets (token)

## Use case

AI agents invoke jwt_decoder to trigger actions in SmartTools. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches SmartTools:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "jwt_decoder": {
      "limits": [
        {
          "counter": "jwt_decoder_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on SmartTools (72)

- `remove_duplicates` — Destructive — https://policylayer.com/tools/io-github-9thshini-smart-tools/remove-duplicates.md
- `vat_calculator` — Destructive — https://policylayer.com/tools/io-github-9thshini-smart-tools/vat-calculator.md
- `age_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/age-calculator.md
- `angle_converter` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/angle-converter.md
- `area_converter` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/area-converter.md
- `aspect_ratio_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/aspect-ratio-calculator.md
- `base64` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/base64.md
- `bmi_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/bmi-calculator.md
- `bmr_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/bmr-calculator.md
- `body_fat_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/body-fat-calculator.md
- `case_converter` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/case-converter.md
- `color_converter` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/color-converter.md
- `compound_interest_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/compound-interest-calculator.md
- `cron_parser` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/cron-parser.md
- `csv_to_json` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/csv-to-json.md
- `csv_to_sql` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/csv-to-sql.md
- `date_difference_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/date-difference-calculator.md
- `discount_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/discount-calculator.md
- `due_date_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/due-date-calculator.md
- `electricity_cost_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/electricity-cost-calculator.md
- `energy_converter` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/energy-converter.md
- `file_hash` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/file-hash.md
- `fraction_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/fraction-calculator.md
- `fuel_cost_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/fuel-cost-calculator.md
- `gitignore_generator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/gitignore-generator.md
- `gpa_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/gpa-calculator.md
- `gradient_generator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/gradient-generator.md
- `hash_generator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/hash-generator.md
- `hours_calculator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/hours-calculator.md
- `htaccess_generator` — Execute — https://policylayer.com/tools/io-github-9thshini-smart-tools/htaccess-generator.md
- …and 42 more: https://policylayer.com/tools/io-github-9thshini-smart-tools.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=io-github-9thshini-smart-tools · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-9thshini-smart-tools