# jwt_decode

Decode and analyze JWT tokens, optionally verifying signatures

Agent View of the PolicyLayer registry record for `jwt_decode`. HTML page: https://policylayer.com/tools/alessandroannini-kali-mcp-server/jwt-decode

## Facts

- Tool: `jwt_decode`
- Server: Kali Linux MCP Server (`alessandroannini/kali-mcp-server`) — https://policylayer.com/tools/alessandroannini-kali-mcp-server.md
- Homepage: https://github.com/AlessandroAnnini/kali-mcp-server
- Risk category: Read (Low risk)
- Registry record: grade D, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

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

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

## Why jwt_decode is rated Low

JWT decoding and signature verification are passive operations that retrieve and inspect data from JWT tokens. While signature verification involves cryptographic operations, it does not execute code, modify data, or create side effects. The 'optionally verifying signatures' phrase indicates validation checks rather than token manipulation.

From the tool's own definition: "Tool performs 'decode and analyze JWT tokens, optionally verifying signatures' — these are read-only cryptographic operations that examine token contents without modifying, deleting, or executing code against external systems."

## Use case

AI agents call jwt_decode to retrieve information from Kali Linux MCP Server 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 Kali Linux MCP Server:

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

## Other tools on Kali Linux MCP Server (13)

- `dirb_scan` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/dirb-scan.md
- `jwt_security_test` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/jwt-security-test.md
- `nikto_scan` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/nikto-scan.md
- `nmap_scan` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/nmap-scan.md
- `nuclei_scan` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/nuclei-scan.md
- `retirejs_scan` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/retirejs-scan.md
- `sqlmap_scan` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/sqlmap-scan.md
- `testssl_scan` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/testssl-scan.md
- `vpn_connect` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/vpn-connect.md
- `vpn_disconnect` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/vpn-disconnect.md
- `zap_scan` — Execute — https://policylayer.com/tools/alessandroannini-kali-mcp-server/zap-scan.md
- `security_headers_check` — Read — https://policylayer.com/tools/alessandroannini-kali-mcp-server/security-headers-check.md
- `vpn_status` — Read — https://policylayer.com/tools/alessandroannini-kali-mcp-server/vpn-status.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=alessandroannini-kali-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/alessandroannini-kali-mcp-server