T3 Code on Windows

Install T3 Code on Windows with winget or the .exe installer, authenticate Codex, and work around the PATH and app-server problems specific to Windows.

Last reviewed 2026-07-27 · verified against the pingdotgg/t3code repo

Windows is the platform with the most sharp edges, almost all of them in the layer below T3 Code — how Windows spawns processes and resolves PATH.

Install with winget#

winget install T3Tools.T3Code

Then launch T3 Code from the Start menu. To upgrade later:

winget upgrade T3Tools.T3Code

Install from the .exe#

Prefer a manual install, or need a specific version? Download the .exe from the releases page and run it. Windows SmartScreen may warn you about an unrecognised publisher; choose More info → Run anyway if you're satisfied the download came from the official repository.

Or skip the install entirely#

npx t3@latest

Works in PowerShell, Command Prompt, and Windows Terminal, provided Node.js is on your PATH.

Set up Codex first#

This is not optional. In PowerShell:

npm i -g @openai/codex
codex login
codex --version

If codex --version fails here, T3 Code has no chance. Fix it at this level first.

Windows-specific issues#

"failed to start codex app-server"#

Reported against the Codex CLI itself on Windows, sometimes surfacing as os error 3 (the system cannot find the path specified). It usually means the Codex binary path resolution failed — a stale npm global prefix, a broken shim, or a path with characters the spawn call mishandles. Walkthrough →

Port conflicts#

T3 Code wants port 3773. Separately, Codex remote connections use 127.0.0.1:9234, and there are reports of failures when that loopback port is already taken by another process. Check both:

netstat -ano | findstr :3773
netstat -ano | findstr :9234

Then stop the offending process, by PID:

taskkill /PID <pid> /F

More on port conflicts →

WSL#

If your repository lives inside WSL, run the whole stack inside WSL — provider CLI, T3 Code server, everything — and reach it from the Windows browser at localhost:3773. Mixing a Windows-side server with WSL-side code means the agent sees \\wsl$\ paths, and git worktree operations get unreliable fast.

Windows Defender and corporate endpoint tools#

Agent runs spawn a lot of short-lived processes and write files rapidly. On managed machines this can trip heuristics and produce mysterious slowdowns or blocked writes. If agent runs are inexplicably slow, check whether real-time scanning is inspecting your repo directory.

Verify the install#

1. Launch T3 Code; the browser opens at localhost:3773
2. Pick Supervised mode for the first run
3. Add a git repository
4. Ask for hello.js that prints a string
5. Confirm the diff panel populates and the git controls activate

FAQ#

How do I install T3 Code on Windows?#

Run winget install T3Tools.T3Code in PowerShell, or download the .exe from the GitHub releases page. You also need a provider CLI such as Codex installed with npm i -g @openai/codex and authenticated with codex login.

Why does T3 Code say codex is not found on Windows when it works in my terminal?#

Applications launched from the Start menu inherit the environment as it was when you logged in, not your current shell's PATH. Sign out and back in, or reboot, after installing Codex globally.

Does T3 Code work with WSL?#

Yes, but run the provider CLI and the T3 Code server both inside WSL and connect from the Windows browser. Splitting them across the boundary causes path and git worktree problems.

What ports does T3 Code use on Windows?#

Port 3773 for the T3 Code server. The Codex CLI additionally uses 127.0.0.1:9234 for remote connections, and conflicts on that port have been reported as app-server startup failures.