# os_detection

Perform OS detection on the specified target with optional custom arguments.

Agent View of the PolicyLayer registry record for `os_detection`. HTML page: https://policylayer.com/tools/0xpratikpatil-nmapmcp/os-detection

## Facts

- Tool: `os_detection`
- Server: NmapMCP (`0xpratikpatil/nmapmcp`) — https://policylayer.com/tools/0xpratikpatil-nmapmcp.md
- Homepage: https://github.com/0xPratikPatil/NmapMCP
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

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

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

## Why os_detection is rated High

OS detection involves sending crafted network packets to an external target to fingerprint its operating system. This is an active network reconnaissance operation with real-world side effects on external systems. It falls under Execute (triggering external operations) rather than Read, as it actively interacts with remote infrastructure.

From the tool's own definition: "'Perform OS detection on the specified target' — actively probes a remote host to fingerprint its operating system"

## Use case

AI agents invoke os_detection to trigger actions in NmapMCP. 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 NmapMCP:

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

## Other tools on NmapMCP (14)

- `arp_discovery` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/arp-discovery.md
- `disable_dns_resolution` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/disable-dns-resolution.md
- `dns_brute_force` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/dns-brute-force.md
- `fin_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/fin-scan.md
- `idle_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/idle-scan.md
- `no_portscan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/no-portscan.md
- `ping_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/ping-scan.md
- `portscan_only` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/portscan-only.md
- `scan_top_ports` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/scan-top-ports.md
- `syn_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/syn-scan.md
- `tcp_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/tcp-scan.md
- `udp_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/udp-scan.md
- `version_detection` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/version-detection.md
- `list_scan` — Read — https://policylayer.com/tools/0xpratikpatil-nmapmcp/list-scan.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`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=0xpratikpatil-nmapmcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/0xpratikpatil-nmapmcp