One model writes, another reviews — in a loop, until both approve.
DT Duet runs duetcode inside
VS Code: Claude implements your task, Gemini reviews the diff against your
tests and linters, and you watch both sides of the conversation live.
Features
Duet panel — per round, the writer's stream (tool actions, code,
explanation) stacks above the reviewer's block (check results, review,
verdict with blockers), each full-width.
Sessions sidebar — every past run from .duet/sessions, with outcome
icons; click to replay any session round by round, patches included.
Task composer — type a task, toggle auto (models loop unattended
until mutual approval) or plan (plan → review → approve → execute).
Screenshots — attach with the picker or paste directly with Cmd+V;
pasted images are cleaned up after the task.
Approvals as buttons — when a model needs your call (review now?
fix issues? guidance when the models deadlock), it's a click, not a
terminal prompt.
Secure keys — API keys live in your OS keychain via VS Code
SecretStorage and are injected only into the spawned dt process. Claude
CLI users need no Anthropic key at all.
Requirements
The dt binary — cargo install --git https://github.com/harsha509/duetcode
(set dt.binaryPath if it's not on VS Code's PATH, e.g. ~/.cargo/bin/dt).
A git repository — the extension offers to run dt init for you the first
time you start a task in a project that is not set up yet.
Gemini API key — add it via the ⚙ gear (stored in the keychain) or export
GEMINI_API_KEY.
Claude CLI authenticated (claude → /login), or an Anthropic API key.
Quick start
Open a git project (accept the dt init prompt if it appears).
Click the DT Duet icon in the activity bar.
Hit + (New Task), type what you want, press Enter.
Watch Claude write and Gemini review; answer prompts with the buttons.
Settings live behind the ⚙ gear (sidebar title or panel): API keys,
Claude CLI login, binary path, writer model.
Security
Keys: OS keychain only — never settings.json, never synced, never logged.
dt.binaryPath is machine-scoped, so a cloned repo's workspace settings
cannot redirect the extension to an untrusted binary.
The extension talks to dt serve over stdio only; no network ports.
Model providers (Anthropic, Google) receive your diffs and prompts, as
with any AI coding tool.
Development
cd editors/vscode
npm install
npm run compile # or press F5 for an Extension Development Host
The extension is a thin client over dt serve's JSON-lines protocol —
see src/serve.rs in the repo root. Releasing: see RELEASING.md.
