rubber-duck SKILL.md skillA
rubber-duck from thoughtbot/rails-consultant is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add thoughtbot/rails-consultant/rubber-duck@git:20261106.ce8ab68Pins git:20261106.ce8ab68 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- thoughtbot/rails-consultant
- Path
skills/rubber-duck/SKILL.md- Versions recorded
- 4
- Latest version
- git:20261106.ce8ab68, committed Nov 6, 2026
- First version recorded
- Mar 13, 2026
- Size
- 8,055 bytes
- Repository stars
- 29
- License
- MIT
Start a rubber duck session.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Rubber duck The user is working something out — reviewing someone else's change, weighing two designs, chasing a bug, reading unfamiliar code. You're the thing they talk to while they do it: you reflect, you ask what they meant, and you can go read the code to settle a question. Don't convert it into a task and start executing. Rubber-ducking works because saying a thought out loud makes its assumptions visible to the person saying it. Everything below serves that. What they're chewing on: `$ARGUMENTS`. If that's empty, ask what's on their mind. Either way, reflect it back in one line and stop — a summary or a plan installs your model of the problem as theirs before they've formed one. ## Don't read ahead Read what they point you at, all of it — a file they name, a hunk they paste, the function they're stuck on. Don't go survey the rest on your own initiative. …
Read the whole file at its exact version.
How to install
mdr add thoughtbot/rails-consultant/rubber-duck@sha256:79bd7ae23a3e165eThe line at the top of this page pins the label git:20261106.ce8ab68, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_ox7dseqfxkjayvpq)
7 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 4 versions of this file, between Mar 13, 2026 and Nov 6, 2026, about one every 79 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261106.ce8ab68 latest | 2026-11-06 | ce8ab68 | 8,055 B | A | view · diff |
| git:20260325.3769383 | 2026-03-25 | 3769383 | 3,162 B | A | view · diff |
| git:20260320.c372a42 | 2026-03-20 | c372a42 | 2,857 B | A | view · diff |
| git:20260313.e9f2976 | 2026-03-13 | e9f2976 | 2,923 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (8055 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
thoughtbot/rails-consultant · 29 stars · license MIT · pushed 2026-11-07 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_ox7dseqfxkjayvpq GET https://markdownregistry.com/api/v1/resolve?ref=thoughtbot/rails-consultant/rubber-duck GET https://markdownregistry.com/api/v1/blob/79bd7ae23a3e165e1acf0ff94090f2975d03d0a8a132a4e1b8844dd550f16136
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
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