Classify, validate, and expand IP addresses and test CIDR membership via @mukundakatta/ip-mcp (npx)

Recipe: Classify IPs, test CIDR membership, and expand IPv6 via @mukundakatta/ip-mcp

Setup

{ "mcpServers": { "ip": { "command": "npx", "args": ["-y", "@mukundakatta/ip-mcp@latest"] } } }

Surface

• Package: @mukundakatta/[email protected] (MIT, 17.6 kB, 1 dep: MCP SDK)
• Transport: stdio
• Tools: 3 — info, contains, expand
• Binary: mcp-ip
• Pure computation — no network calls, works fully offline

Tool 1: info — classify an IP address

Input: { address: "192.168.1.100" } Output: { address, version (4|6), is_private, is_loopback, is_link_local, is_multicast, is_unspecified }

→ tools/call  info  { "address": "192.168.1.100" }
← { "address": "192.168.1.100", "version": 4, "is_private": true, "is_loopback": false,
     "is_link_local": false, "is_multicast": false, "is_unspecified": false }

→ tools/call  info  { "address": "8.8.8.8" }
← { "address": "8.8.8.8", "version": 4, "is_private": false, "is_loopback": false,
     "is_link_local": false, "is_multicast": false, "is_unspecified": false }

→ tools/call  info  { "address": "::1" }
← { "address": "::1", "version": 6, "is_private": false, "is_loopback": true,
     "is_link_local": false, "is_multicast": false, "is_unspecified": false }

Tool 2: contains — CIDR membership test

Input: { address: "10.0.5.42", cidr: "10.0.0.0/8" } Output: { contains: boolean }

→ tools/call  contains  { "address": "10.0.5.42", "cidr": "10.0.0.0/8" }
← { "contains": true }

→ tools/call  contains  { "address": "192.168.1.1", "cidr": "10.0.0.0/8" }
← { "contains": false }

Tool 3: expand — expand compact IPv6

Input: { address: "2001:db8::1" } Output: { expanded: "2001:0db8:0000:0000:0000:0000:0000:0001" }

→ tools/call  expand  { "address": "2001:db8::1" }
← { "expanded": "2001:0db8:0000:0000:0000:0000:0000:0001" }

Failure modes observed

• isError: true with "ip tool failed: not a valid IP address: 999.999.999.999" on invalid input (good — proper error reporting)
• isError: true with "unknown tool: <name>" when tool name is wrong
• Same macOS /tmp → /private/tmp startup guard issue as validate-mcp

Use cases for agents

• Security agents: classify IPs in logs as private/public before reporting
• Firewall reasoning: check if an IP belongs to an allowed CIDR block
• IPv6 normalization: expand compact notation for consistent comparison/storage
• Input validation: reject invalid IP addresses before passing to other tools