y is a self-modifying desktop coding-agent app.
It is built around a simple idea: software should become malleable while you use it. The main interface is a chat, but the app can reshape its own UI through a protected Modify surface. You can ask y to change how y itself works, keep the change if it renders safely, or roll it back if it does not.
y is not a new agent model. It is a local, chat-first workspace for the coding agents you already use: Claude Code, OpenAI Codex, and other CLI-native agents over time.
Most coding-agent apps are fixed products. You can use them, configure them, maybe install plugins, but the product itself still belongs to someone else.
y is different. It treats the app as malleable software:
- Chat first. The default surface is a focused conversation, not an editor clone.
- Self-modifying. The Modify rail can edit the live Userland UI while the protected Kernel stays locked.
- Local agents. Claude Code and Codex run as official local CLIs with the user's own login.
- Parallel work. Chats can use isolated workspaces so agents can work in parallel without stepping on the same files.
- Diff-gated changes. UI changes compile, render, show a diff, and can be kept or discarded.
- Rollback built in. The app keeps known-good snapshots so broken UI changes can recover.
y is split into two parts:
| Layer | What it does |
|---|---|
| Protected Kernel | Auth, local engine adapters, app state, safety rails, filesystem boundaries, terminal bridge, Modify rail, and rollback runway. |
| Mutable Userland | The chat UI and app surface that can be edited live by the user or by Modify. |
This split lets y feel self-modifying without giving the modification agent control over the protected core. The app can change its own interface, but the Kernel still owns the trust boundaries.
y runs coding agents locally instead of proxying them through a hosted account.
- Claude Code uses the official Claude Code CLI.
- Codex uses the official Codex CLI.
- Model and effort settings stay visible in the composer.
- Multiple chats can run against different engines.
- Isolated workspaces let parallel agents work without interfering with each other.
The user's local CLI auth remains the source of truth. y orchestrates the experience; it does not replace the agent providers.
The latest macOS build is published on GitHub Releases:
Current release target: macOS Apple Silicon.
cd app
pnpm install
pnpm devUseful checks:
pnpm typecheck
pnpm test:uiBuild a local macOS bundle:
The generated app artifacts are written to app/dist/ and are intentionally not committed.
y keeps the coding workflow local. Project files, terminal commands, and agent prompts are not sent to y's product analytics.
Product analytics are for app usage health: sign-in state, feature usage, feedback, and missing-brick requests. Missing-brick reports are structured and should describe the missing capability, not the user's private prompt or source code.
y is under active development. The current focus is launch-readiness for macOS: packaging, auth, analytics, local app-state durability, and the self-modifying Modify workflow.
MIT. See LICENSE.