Rubberduck Me
Someone to read the pull request with you.
An animated rubber duck AI pair-reviewer that walks you through GitHub pull requests.
Early access. Available to GitHub organisations that have installed the Rubberduck app.
Open a pull request. The duck shows up.
It reads the diff first
Before saying anything, it reads the whole change — every file, the description, the commit messages — then tells you what the pull request is actually doing.
Then one stop at a time
It walks the change in the order a senior engineer would read it, scrolling to each spot and highlighting it while it explains what it is and where it fits.
Ask it things
Type a question at any point, or select a few lines and ask about those. Reload the page and it remembers where you were.
What it looks like
A summary that read the whole thing
Not a restatement of the title. It has the diff, the description and the commit messages, so it can tell you the point of the change before you start reading it.
Stop by stop, with the code in front of you
Each stop scrolls to its lines and boxes them, so you are always looking at the thing being explained rather than hunting for it.
Questions, in context
It answers with the diff and the rest of the tour already in mind, then puts you back where you left off.
Explorer mode
Linger somewhere off the tour and it quietly offers to explain what you are looking at. An invitation, not an interruption — and easy to switch off.
How it works
In your browser
- A Chrome extension (Manifest V3).
- The duck is drawn in a shadow DOM overlay, so it cannot collide with GitHub's own styles.
- It finds and highlights lines in the diff you already have open.
- It talks to one server over HTTPS. Nothing else.
On the server
- Fetches the diff from GitHub using your own authorisation.
- Plans the tour with Claude, and answers questions against it.
- Generates the voice, and caches the audio so replays are free.
- Stores tours, your reading progress and your questions in Postgres.
Model and voice API keys live only on the server — the extension never holds them. What data is involved.
Access and permissions
The duck can only ever open a pull request you could already open yourself.
Every request to GitHub is made with your own authorisation, not a shared account. There is no server-side token that can see more than you can.
What it asks for
A GitHub App with two read-only permissions: Metadata and Pull requests. That is the whole list.
What it cannot do
It has no write access of any kind — it cannot push, comment, approve, merge or change a setting. It cannot read repositories your organisation did not include.
Getting in
Access is currently limited to invited organisations. An owner of your GitHub organisation installs the app and chooses which repositories it may read; after that, anyone on the team signs in with GitHub and it works. If you would like your organisation added, get in touch.
Questions
Does my code leave my machine?
Yes. To explain a pull request, the server fetches its diff from GitHub and sends it to Anthropic's Claude API, along with the description and commit messages. Generated narration is also sent to a text-to-speech provider, and can quote your code. The diff is stored so a tour can be reused. This is worth knowing before you point it at anything sensitive — the privacy policy spells out exactly what goes where and how long it is kept.
Can it change anything in my repository?
No. The GitHub App requests read-only permissions and holds no write scope, so pushing, commenting, approving and merging are all impossible for it.
Does it work on private repositories?
Yes, on the ones your organisation chose to include when installing the app — and only for people who can already read them.
Is the review any good?
It is a reading companion, not a reviewer. It explains what a change does and where it fits; it does not judge whether the code is correct, safe or a good idea, and it can be wrong. Treat it as a faster way into unfamiliar code, not as a substitute for review.
Which browsers does it support?
Chrome, and Chromium-based browsers that support Manifest V3 extensions.
What does it cost?
Nothing during early access.