Rubber Ducky

Q: What is a Claude Code skill and how does the Rubber Ducky 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. Rubber Ducky is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the General category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: General · Sub-category: general-misc · Last updated: 2026-06-10

type:review

Use when you've planned a non-trivial change and are about to implement it, finished a complex or multi-file piece of work, just wrote tests, or are stuck on repeated failures — and any time the user says "rubber duck this", "rubber ducky", "get a second opinion", "sanity-check my plan", "poke holes in this", "what am I missing", "critique my approach", "review this before I build it", or "/rubber-ducky". Spawns independent read-only critics on DIFFERENT Claude models than the one driving the session to catch blind spots, design flaws, and substantive bugs while course corrections are still cheap. Skip it only for small, obvious, well-understood changes. Do NOT use for reviewing a finished diff or PR — use /review for that; rubber-ducky pressure-tests your own in-progress thinking before and during implementation.

Security AStatic scan found no risk patternsHow grading works ›

From the source SKILL.md

A built-in critic. Before committing to a non-trivial change, you stop, articulate your current thinking, and have it scrutinized by independent reviewers running on different models than the one driving this session. Unlike a real rubber duck, this one talks back: it returns a structured critique you can act on.

What this skill does

Rubber Ducky is a community-contributed Claude Code skill in the general-misc sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/rubber-ducky/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when you've planned a non-trivial change and are about to implement it, finished a complex or multi-file piece of work, just wrote tests, or are stuck on repeated failures — and any time the user says "rubber duck this", "rubber ducky", "get a second opinion", "sanity-check my plan", "poke holes in this", "what am I missing", "critique my approach", "review this before I build it", or "/rubber-ducky". Spawns independent read-only critics on DIFFERENT Claude models than the one driving the session to catch blind spots, design flaws, and substantive bugs while course corrections are still cheap.

Who uses this skill

The Rubber Ducky Claude Code skill is built for Claude Code users and developers across all disciplines looking for general-purpose AI assistance. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 196,000+ 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/rubber-ducky
curl -L https://claudskills.com/skills/rubber-ducky/SKILL.md \
  -o ~/.claude/skills/rubber-ducky/SKILL.md

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

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

📱 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 Rubber Ducky Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/rubber-ducky/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.

What does the Rubber Ducky skill do?

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 Rubber Ducky skill?

Use Rubber Ducky when your Claude Code task falls under the General category — specifically in the general misc 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 Rubber Ducky" or describe the task and let Claude pick). Browse related skills at /category/general/.

What is a Claude Code skill and how does the Rubber Ducky 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. Rubber Ducky is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the General category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Source: https://github.com/harnessprotocol/harness-kit/blob/HEAD/plugins/rubber-ducky/skills/rubber-ducky/SKILL.md
License: Apache-2.0
Author: harnessprotocol
Website: https://harnesskit.ai

Cite this skill

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

APA

harnessprotocol. (2026). Rubber Ducky [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/rubber-ducky/

BibTeX

@misc{rubber-ducky-2026,
  author    = {harnessprotocol},
  title     = {Rubber Ducky [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/rubber-ducky/}
}

Embed this skill

Promote, attribute, or link this skill from your own README, blog post, or documentation. All three snippets are free to use — no sign-up, no API key. More distribution surfaces →

Badge

[![ClaudSkills](https://claudskills.com/badge/rubber-ducky.svg)](https://claudskills.com/skills/rubber-ducky/?utm_source=badge&utm_medium=readme&utm_campaign=skill_badge)

Security scan

Grade A · scanned 2026-09-28 — free static scan against the OWASP Agentic Skills Top 10.

No risk patterns were found in any of the ten OWASP-aligned categories. How grading works ›

✓ Prompt injection
✓ Data exfiltration
✓ Supply chain
✓ Reverse shell
✓ Credentials
✓ Execution
✓ Filesystem
✓ Persistence
✓ Obfuscation
✓ Network

Show this grade on your repo (click to copy):

[![Security: A](https://img.shields.io/badge/Security-A-2e7d32)](https://claudskills.com/skills/rubber-ducky/#security)

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Part of ClaudSkills — the open registry for Claude Skills & Claude Code Skills. · What's New · Install guide · About · llms.txt

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