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ClaudSkills / Product / prd-spec

Do Reverse Spec

Category: Product  ·  Sub-category: prd-spec  ·  Last updated:
lang:ruby
ALWAYS use when extracting functional specifications from existing code that lacks documentation. Supports two perspectives: (1) product-feature specs that analyze multiple source files to describe a product capability from the user's viewpoint, and (2) module-level technical specs for binary formats, protocols, state machines, algorithms, or APIs. Works with natural language ('로직 제어 기능 명세 작성해줘') or slash command arguments. ALWAYS use when user mentions: 역공학 명세, reverse engineering spec, 코드 기반 명세, code-based specification, 기능 명세 추출, extract functional spec, 바이너리 구조 명세, binary structure spec, 프로토콜 명세, protocol specification, 상태 머신 명세, state machine spec, 알고리즘 명세, algorithm specification, 코드에서 문서 생성, generate docs from code, 설계 의도 추출, design intent extraction, 명세서 역공학, spec reverse engineering, 제품 기능 명세, product feature spec, 기능 사양서, functional specification, 동작 명세, behavior specification, 코드 분석 후 명세 작성, 기능 스펙 문서, 사양서 작성. Do NOT use for: API header documentation (use do-apidoc), code quality audit (use plan-quality-audit), data flow tracing without spec output (use plan-dataflow), or designing new function contracts from scratch (use plan-function-spec).
Security AStatic scan found no risk patternsHow grading works ›

About this skill (catalog notes)

Do Reverse Spec includes 5 code blocks for direct copy-paste. The SKILL.md runs to about 1,184 words, in the catalog's typical mid-range.

Original author
solitasroh
Indexed lastmod
Catalog position
Product · prd-spec
Indexed related skills
10

How Do Reverse Spec fits the catalog

Do Reverse Spec sits in the Product category under the prd-spec sub-topic in the ClaudSkills catalog. There are 10 related skills indexed alongside it; comparing a few before installing usually reveals which fits your workflow best.

These notes are auto-generated from features detected in the SKILL.md file and from this catalog's structure — they aren't part of the source repository.

From the source SKILL.md

<!-- BEGIN: cycle3-body-neutral -->

What this skill does

Do Reverse Spec is a community-contributed Claude Code skill in the prd-spec sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/do-reverse-spec/ and loads when your prompt matches the skill's trigger.

When to invoke it: use when extracting functional specifications from existing code that lacks documentation. Supports two perspectives: (1) product-feature specs that analyze multiple source files to describe a product capability from the user's viewpoint, and (2) module-level technical specs for binary formats, protocols, state machines, algorithms, or APIs.

Who uses this skill

The Do Reverse Spec Claude Code skill is built for product managers, product designers, and cross-functional teams planning, shipping, and measuring product features. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 146,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/do-reverse-spec
curl -L https://claudskills.com/skills/do-reverse-spec/SKILL.md \
  -o ~/.claude/skills/do-reverse-spec/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/do-reverse-spec/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/do-reverse-spec/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\do-reverse-spec\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Telegram

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Do Reverse Spec Claude Code skill?
Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/do-reverse-spec/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.
What does the Do Reverse Spec skill do?
ALWAYS use when extracting functional specifications from existing code that lacks documentation. Supports two perspectives: (1) product-feature specs that analyze multiple source files to describe a product capability from the user's viewpoint, and (2) module-level technical specs for binary formats, protocols, state machines, algorithms, or APIs. Works with natural language ('로직 제어 기능 명세 작성해줘') or slash command arguments. ALWAYS use when user mentions: 역공학 명세, reverse engineering spec, 코드 기반 명세, code-based specification, 기능 명세 추출, extract functional spec, 바이너리 구조 명세, binary structure spec, 프로토콜 명세, protocol specification, 상태 머신 명세, state machine spec, 알고리즘 명세, algorithm specification, 코드에서 문서 생성, generate docs from code, 설계 의도 추출, design intent extraction, 명세서 역공학, spec reverse engineering, 제품 기능 명세, product feature spec, 기능 사양서, functional specification, 동작 명세, behavior specification, 코드 분석 후 명세 작성, 기능 스펙 문서, 사양서 작성. Do NOT use for: API header documentation (use do-apidoc), code quality audit (use plan-quality-audit), data flow tracing without spec output (use plan-dataflow), or designing new function contracts from scratch (use plan-function-spec).
Is this skill free to install?
Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.
When should I use the Do Reverse Spec skill?
Use Do Reverse Spec when your Claude Code task falls under the Product category — specifically in the prd spec area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Do Reverse Spec" or describe the task and let Claude pick). Browse related skills at /category/product/.
What is a Claude Code skill and how does the Do Reverse Spec skill fit in?
A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Do Reverse Spec is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Product category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA
solitasroh. (2026). Do Reverse Spec [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/do-reverse-spec/
BibTeX
@misc{do-reverse-spec-2026,
  author    = {solitasroh},
  title     = {Do Reverse Spec [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/do-reverse-spec/}
}

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Security scan

Grade A · scanned 2026-07-06 — free static scan against the OWASP Agentic Skills Top 10.

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