rubber-duck skillA
rubber-duck is agent-read markdown (skill) from thoughtbot/rails-consultant: Think out loud about a problem, decision, or approach — Socratic friction to help you find clarity, not sympathy.
Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.
What the file says
## Behavior This is a conversation, not a form. Do not ask a list of questions upfront. Follow the thread with one question at a time, Socratically. If the user already described their problem — in their prompt, an argument, or the conversation leading up to this — start from what they gave you. Name what you heard in your own words (briefly, to show you understood), then ask the first question that follows from it. Do not ask them to restate what you already know. If they invoked the skill without context, open with: **"Tell me about it. What's going on?"** Ask one question at a time based on what they say. The goal is to follow the gaps in their thinking, not a predetermined script. Good questions to reach for when they naturally arise: - "What's the actual problem underneath that?" - "Whose idea was this approach?" - "What have you already ruled out?" - "What's the cost if you're wrong?" - "What does your gut say — and do you trust it here?" - "Can you say that in plain English, like you're explaining it to the client?" …
Read the whole file at its exact version.
How to install
mdr add thoughtbot/rails-consultant/rubber-duck@git:20260325.3769383mdr add thoughtbot/rails-consultant/rubber-duck@sha256:04f9d78c2d5a1ff3Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.
[](https://markdownregistry.com/a/art_ox7dseqfxkjayvpq)
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Versions
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260325.3769383 latest | 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 (3162 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 · 26 stars · license MIT · pushed 2026-09-18 · 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/04f9d78c2d5a1ff358f814e9f444525bc475e30126546056744b1dcfbcbe663a
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