packet-chef-mcp

packet_detect_dns_tunneling

Detects DNS tunneling and data exfiltration in PCAP captures by analyzing subdomain entropy, label lengths, character encodings, and CDN patterns.

Instructions

Identifies DNS data exfiltration and tunneling channels (e.g. dnscat2, iodine, Cobalt Strike DNS beacons). Analyzes Shannon character entropy, subdomain label lengths, character set encodings (hex/base32/base64), and CDN heuristics.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

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

Input Schema

Name	Required	Description
`input`	No	Base64-encoded PCAP file bytes (max 10MB).
`filePath`	No	Absolute path to a PCAP file on disk (local stdio only).
`minSubdomains`	No	Minimum unique subdomains under a parent domain to trigger analysis (default: 15).

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.0.1Oct 1, 2026

TDQS

A3.6/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It usefully discloses the detection methodology (Shannon entropy, label lengths, hex/base32/base64 encodings, CDN heuristics), which is genuine behavioral context, but says nothing about I/O format, cost/performance, whether it is read-only, or how a detection is reported.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two dense sentences, front-loaded with the purpose and then the technique list. No filler or restatement of the name.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a stateless PCAP analyzer with a fully documented schema and no output schema, the description is nearly sufficient: it explains what it detects and how. It stops short of noting input requirements or result shape, which for a no-output-schema tool would have been a useful addition.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so input, filePath, and minSubdomains are all self-documented, and the description adds no parameter-level detail. Baseline 3 applies when the schema does all the work.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Identifies') and a narrow resource ('DNS data exfiltration and tunneling channels') with named threat examples (dnscat2, iodine, Cobalt Strike DNS beacons). This inherently separates it from packet_extract_dns (record extraction) and packet_entropy, but it never explicitly addresses overlap with the sibling packet_detect_beacons, which also covers DNS beacons.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The threat examples imply when the tool is relevant (hunting for covert DNS channels), but there is no explicit 'use this when / use X instead' guidance and no mention of the prerequisite PCAP input. With packet_detect_beacons as a close sibling, routing guidance would materially help.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server