# arp_discovery

Perform ARP discovery on the specified target with optional custom arguments.

Agent View of the PolicyLayer registry record for `arp_discovery`. HTML page: https://policylayer.com/tools/0xpratikpatil-nmapmcp/arp-discovery

## Facts

- Tool: `arp_discovery`
- 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": "arp_discovery",
    "arguments": {}
  }
}
```

## Why arp_discovery is rated High

ARP discovery is an active network reconnaissance operation that sends packets to external targets. It falls under Execute because it triggers external network operations whose effects depend on the target argument.

From the tool's own definition: "'Perform ARP discovery on the specified target' — actively sends ARP packets to enumerate live hosts on a network segment"

## Use case

AI agents invoke arp_discovery 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": {
    "arp_discovery": {
      "limits": [
        {
          "counter": "arp_discovery_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on NmapMCP (14)

- `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
- `os_detection` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/os-detection.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