Sigma Code

Sigma Code is an independently maintained desktop, web, and mobile client for coding agents. It is a downstream fork of T3 Code with a first-party Sigma provider connected over the open Agent Client Protocol (ACP).

Sigma Code is not affiliated with, sponsored by, or endorsed by T3 Tools, Inc. The original T3 Code copyright and MIT license are preserved in LICENSE; downstream and third-party attribution is documented in NOTICE and THIRD_PARTY_NOTICES.md.

Current status

Official Windows x64 installers are published in the Sigma Releases. Each installer contains this desktop UI and the exact verified Sigma Runtime from the same release, so a separate Node.js or Agent CLI installation is not required. Release builds use that Sigma repository as their automatic-update channel.

Windows installers remain unsigned previews until a trusted signing identity is available, so SmartScreen or Smart App Control may warn or block them. A hosted Connect service is not configured, and cloud features stay disabled by default.

The retained upstream marketing site is reference source only and is disabled from development, preview, build, and deployment in this downstream.

The application uses its own identities and state:

• executable: sigma-code
• URL scheme: sigmacode
• application ID: io.github.hututuqqq.sigmacode
• state directory: ~/.sigma/code

It never migrates, reads, or writes ~/.t3 or the official T3 Code application data.

The default path is Sigma Runtime + ChatGPT subscription (experimental). In the Windows desktop app, choose a Sigma subscription model and click Login with ChatGPT once. Sigma keeps running the task, tools, recovery, reviewer, strategist, and persistence; model requests use the ChatGPT/Codex subscription allowance and do not require OPENAI_API_KEY. Authentication, allowance, and network failures are shown directly and never trigger a silent fallback to another paid provider.

Sigma Runtime's model layer is backed by the pinned Pi directory. Settings shows one searchable model connection per underlying provider, with API-key and OAuth methods supplied by the trusted Runtime. The full 1,100+ model catalog remains searchable without rendering every model in the default picker. Models with unverified pricing require explicit confirmation for the current task and are shown as “Price unknown”, never as $0.

Sigma Code also retains the upstream providers. Install and authenticate any separate provider you intend to use:

• Sigma Runtime + Pi model connections: desktop artifacts include a verified Sigma Runtime; ChatGPT, API-key, and supported OAuth logins are managed from Sigma Code
• Codex CLI（独立 Agent）: install Codex CLI and run codex login
• Claude: install Claude Code and run claude auth login
• Cursor: install Cursor CLI and run cursor-agent login
• Grok Build: install Grok Build CLI and run grok login
• OpenCode: install OpenCode and run opencode auth login

Development

Install the repository toolchain and dependencies:

curl -fsSL https://vite.plus | bash
vp install

On Windows:

irm https://vite.plus/ps1 | iex
vp install

Start the web and server development stack:

vp run dev

Start the desktop development build:

vp run dev:desktop

The Sigma provider automatically starts the long-lived local ACP server with sigma acp.

Desktop artifacts must be built with a verified portable Runtime produced by the Sigma repository:

$env:SIGMACODE_DESKTOP_SIGMA_RUNTIME = "C:\path\to\sigma\.artifacts\agent-cli-win32-x64"
vp run dist:desktop:win:x64

The build rejects missing or incomplete Runtime bundles so a distributable installer cannot silently ship without the Sigma provider.

Documentation

• Getting started
• ChatGPT subscription login
• Architecture overview
• Provider guides
• Operations
• Syncing stable T3 releases

See CONTRIBUTING.md before submitting downstream changes.