protocol-reverse-engineering

protocol-reverse-engineering is a skill for Claude Code, Codex from beel-collab/presets.dev. It costs 21 tokens per session (276 once invoked), scanned A, original, MIT.

A guide to discovering how an unfamiliar network protocol works by capturing, analyzing, and documenting its messages and behavior.

In plain words
What is it for?
Use it to plan protocol investigations, choose inputs and checks, and verify your findings.
Why use it?
It gives you a structured way to understand undocumented communication, which helps with security research, compatibility work, and debugging.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to plan protocol investigations, choose inputs and checks, and verify your findings.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/beel-collab/presets.dev/protocol-reverse-engineering
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add beel-collab/presets.dev --skill protocol-reverse-engineering
Clone the repo
git clone --depth 1 https://github.com/beel-collab/presets.dev

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for protocol-reverse-engineering

README.md
[![agentmods](https://agentmods.dev/badge/skills/beel-collab/presets.dev/protocol-reverse-engineering/github.svg)](https://agentmods.dev/skills/beel-collab/presets.dev/protocol-reverse-engineering)
Your own site
<a href="https://agentmods.dev/skills/beel-collab/presets.dev/protocol-reverse-engineering"><img src="https://agentmods.dev/badge/skills/beel-collab/presets.dev/protocol-reverse-engineering/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for protocol-reverse-engineering

Your own site · 80×15
<a href="https://agentmods.dev/skills/beel-collab/presets.dev/protocol-reverse-engineering"><img src="https://agentmods.dev/badge/skills/beel-collab/presets.dev/protocol-reverse-engineering.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 276 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00021 $0.00276
Opus 5 $0.00010 $0.00138
Sonnet 5 $0.00004 $0.00055
Haiku 4.5 $0.00002 $0.00028

Measured 5d ago against content hash a8163d716554, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

protocol-reverse-engineering scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

claude/skills/security/protocol-reverse-engineering/SKILL.md · 39 lines

What it actually says

Protocol Reverse Engineering

Comprehensive techniques for capturing, analyzing, and documenting network protocols for security research, interoperability, and debugging.

Use this skill when

  • Working on protocol reverse engineering tasks or workflows
  • Needing guidance, best practices, or checklists for protocol reverse engineering

Do not use this skill when

  • The task is unrelated to protocol reverse engineering
  • You need a different domain or tool outside this scope

Instructions

  • Clarify goals, constraints, and required inputs.
  • Apply relevant best practices and validate outcomes.
  • Provide actionable steps and verification.
  • If detailed examples are required, open resources/implementation-playbook.md.

Resources

  • resources/implementation-playbook.md for detailed patterns and examples.

Limitations

  • Use this skill only when the task clearly matches the scope described above.
  • Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
  • Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 39 lines · 21 tokens per session scan A a8163d716554

Subscribe to this mod's changes

protocol-reverse-engineering is a skill published in the GitHub repository beel-collab/presets.dev (2 stars, last pushed 4mo ago), licensed MIT. It adds 21 tokens to every session and 276 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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