TL;DR

T3 Code (pingdotgg/t3code) is a free, open-source app for running the coding agents you already pay for (Claude Code, Codex, Cursor, Grok Build, OpenCode, Google Antigravity, Pi and a few more) from one interface. It ships as a desktop app, a web app, iOS and Android apps, and a t3 command-line server. The agents run on your machine; T3 Code is the screen, the thread list, the diff viewer and the remote control.

Facts as of October 30, 2026:

  • 32,240 GitHub stars, 8,554 forks. The repo was created on February 8, 2026.
  • 1,397 open issues (issues only, not pull requests).
  • License: MIT.
  • Latest stable release: v0.1.5, published October 29, 2026. Nightly builds ship several times a day (v0.1.6-nightly.20261030.3917 went out this morning).
  • Built by the team behind T3 Chat and the T3 stack — Theo Browne and Julius Marminge are among the top contributors.

Not run by us: our hands-on lab (a throwaway GitHub Actions container) could not start today because GitHub refused the job over a billing limit on the account. Everything below comes from the README, the user docs in the repository, the v0.1.5 release notes, the t3 npm package and install script, and public community threads. We did not install T3 Code or drive an agent with it.

Our verdict: T3 Code is the most complete open-source “control surface” for coding agents we have looked at, and its real advantage is remote work: one server on a desktop or VPS, driven from a phone, a browser or another laptop, without forwarding ports. The catches are that it is early (version 0.1.x, a self-described “expect bugs” project), new threads default to Full access, telemetry is on by default, and there is no local-model support by design.

Quick Reference

FieldValue
What it isGUI and remote control for coding agents you already have installed
Supported agentsClaude Code, Codex, Cursor, Grok Build, OpenCode, Antigravity, Pi, Muse Code, fx
ClientsDesktop (Electron), web (app.t3.codes), iOS, Android
Servert3 CLI, default port 3773
Installcurl -fsSL https://t3.codes/install.sh | sh or npx t3@latest
PriceFree; you pay your agent providers as before
Remote accessT3 Connect (free, up to 3 machines), LAN pairing, Tailscale, SSH
MCP serverYes — outside agents can read and start threads
Local modelsNot supported
LicenseMIT
Latest stablev0.1.5 (October 29, 2026)

What T3 Code Actually Is

The project calls itself an “agent harness control surface”, and its own FAQ is careful about the distinction. A harness is the thing that turns a model into an agent: it gives the model tools, runs them and returns the results. Claude Code sits on Anthropic’s Agent SDK; Codex sits on the Codex App Server. T3 Code is neither. It uses those harnesses and does not work without at least one of them installed and logged in.

The FAQ’s metaphor: the model is the chef, the harness is the kitchen, and T3 Code “is the restaurant that lets you bring whatever kitchen you want.”

In practice that means:

  1. You install and authenticate one or more agent CLIs on a machine (claude auth login, codex login, agent login for Cursor, and so on).
  2. You run the T3 Code server on that same machine.
  3. You open threads from the desktop app, the browser, or your phone. Each thread is one agent conversation working in a project folder, optionally in its own Git worktree.

Because every agent appears through the same thread view, switching from Claude to Codex for a task is a model-picker change rather than a different app. The team’s pitch is exactly that: “Every harness feels nearly identical in here, so you can stop worrying about harnesses and focus on building.”

T3 Code first appeared in March 2026 as a thin web UI around Codex. Early reviews described Claude support as a pending pull request. Seven months later it covers nine providers, has native mobile apps in both stores, and went through a burst of releases: v0.1.0 shipped on October 15 and v0.1.5 on October 29. It picked up 2,142 stars in the week to October 30 on GitHub Trending.

The v0.1.5 notes also add Claude and GPT models and thinking levels when driving Google Antigravity, and in October the repository started syncing to GitCafe — per a Hacker News post, about 18,000 PRs and 4,000 issues.

Key Features

Bring your own subscription

There is no T3 Code plan. The FAQ is blunt: “There’s no way to pay us to use T3 Code.” You use your existing Claude, ChatGPT, Cursor or Grok subscriptions through their official CLIs. The FAQ adds that T3 Code is within the terms of service for Claude Code, Codex and Antigravity, that the Grok Build and Cursor integrations were built with those vendors, and that other providers use official ACP (Agent Client Protocol) bindings.

If you prefer API keys, each provider can have extra instances with their own environment variables, so you can keep a subscription account and an OpenRouter-backed Claude side by side.

Threads, worktrees and diffs

A thread can run in the project directory or in a new worktree, so parallel agents do not trample each other’s changes. The diff pane shows only what a given turn changed: if the agent pulled or rebased, files that Git brought in are left out. A commit view lists the newest 100 commits in the branch comparison.

Threads no longer need a project. A “No project” thread works in a scratch folder under ~/.t3/scratch, and v0.1.5 added Turn into project for when a throwaway task becomes real work.

Source control integrations cover GitHub, GitLab, Forgejo, Gitea, Bitbucket, Azure DevOps and GitCafe for cloning, publishing and opening pull requests.

Remote access is the headline

This is where T3 Code separates from the Codex desktop app or Claude Desktop. The server runs wherever your code lives and you connect from anywhere:

# On a VPS or home desktop
curl -fsSL https://t3.codes/install.sh | sh
t3 connect          # sign in to T3 Connect, offers to install a background service

Then sign in to the same account on your phone or at app.t3.codes and pick the machine. T3 Connect rides a Cloudflare tunnel (cloudflared on your machine); the docs say the relay sets up the link but does not proxy your HTTP or WebSocket sessions, and that your code and prompts go straight from your machine to your provider.

Alternatives if you do not want an account:

# LAN or tailnet pairing: prints a pairing URL and QR code
t3 serve --host 192.168.1.20

# New pairing link for an already-running server
t3 pair

# Tailscale HTTPS
t3 serve --tailscale-serve

The desktop app can also add an SSH environment: give it user@host, and it starts or reuses a server there and handles the port forward. The remote host must be Linux or an Apple Silicon Mac.

A machine can have several routes (LAN, Tailscale, T3 Connect, SSH); T3 Code uses the first one that answers.

T3 Connect is free for up to 3 machines per account; phones and browsers do not count. Linking a paid T3 Chat plan raises that to 10 (Pro) or 100 (Premier). The FAQ notes they “may have to change course” if the bill becomes unacceptable.

An MCP server for outside agents

Every environment exposes an MCP endpoint at /mcp. Claude Code or Codex in your own terminal, ChatGPT, or a bot can connect, read projects and threads, and — if you grant it — start and message threads:

claude mcp add --transport http t3 https://<environment-address>/mcp
claude mcp login t3

Access defaults to Read only. Higher levels let the outside agent start threads, but a thread it starts cannot run with more permissions than the level you granted. Sign-in only completes over HTTPS or localhost, so a plain-HTTP LAN address is not enough.

Usage across providers

A Usage view combines token use, cache savings and estimated API-equivalent cost across providers. The docs stress these are estimates, not your subscription bill.

Getting Started

The CLI installer needs only sh, tar, a SHA-256 tool and curl or wget. It downloads a self-contained build for your platform from the GitHub release, checks it against the release’s SHA256SUMS, and puts a t3 link in ~/.local/bin:

curl -fsSL https://t3.codes/install.sh | sh
t3                       # start the server and open the web app
t3 serve                 # start without opening a browser
t3 service install       # keep it running in the background (macOS, Linux)
t3 update                # move to a newer release
t3 doctor                # reclaim database space and run repairs

To try it once: npx t3@latest (Node.js 20.11 or newer). The npm package is a small launcher that fetches the same release archive. Set T3CODE_CHANNEL=nightly for the nightly train or T3CODE_VERSION to pin a version.

Desktop builds are on GitHub Releases and in the usual package managers:

brew install --cask t3-code        # macOS
winget install T3Tools.T3Code      # Windows
yay -S t3code-bin                  # Arch

There is no t3 CLI binary for Intel Macs (the desktop app works there), and Windows background services are not supported. Then enable your agents in Settings → Providers; if one is missing, the FAQ says it is almost always a CLI not on the server’s PATH, fixed with the Binary path field.

Things to Check Before You Adopt It

New threads default to Full access

The permission-mode docs say the initial default for new threads is Full access: commands and edits run without approval prompts. The other modes are Supervised (asks for commands and file changes), Auto-accept edits, and Auto (the provider’s own automatic review). Providers enforce these differently; OpenCode and Antigravity have no automatic review, so Auto falls back to asking there.

If you are pointing agents at anything you care about, change the default in Settings → Threads → New threads → Permissions before the first prompt. This matters more with remote access: a phone that can start threads on your workstation is a phone that can run shell commands on it.

Telemetry is on unless you turn it off

The server sends product usage events to ingest.t3.codes, which forwards them to PostHog. They include provider, model, reasoning effort, permission mode, turn result, duration and token totals, plus hashed identifiers for your T3 Connect, OpenAI and Claude accounts. The docs state that prompts, responses, file contents and tokens are not included. Relay traces go to Axiom. Set T3CODE_TELEMETRY_ENABLED=false in the server’s environment to stop both. The mobile apps send crash reports separately, with their own toggle.

Claude subscription limits can drain faster

The FAQ admits that T3 Code drives Claude through Anthropic’s Agent SDK and that “all Agent SDK usage will drain your 5h limits faster than using Claude Code directly.” It says weekly limits are not affected and that the bug has been reported to Anthropic. Heavy Claude Max users should watch the 5-hour window during the first week.

No local models, on purpose

The FAQ answer is one line: “T3 Code is a serious developer tool. Locally runnable models are not capable of meaningful engineering work.” That stance drew pushback on r/LocalLLaMA when it surfaced in March. If your workflow is Ollama or llama.cpp, look at the Pi coding agent or OpenCode directly.

Early software, closed contributions

The README says “We are very very early in this project. Expect bugs,” and that the project is “(mostly) not accepting contributions yet.” With 1,397 open issues and nightly builds several times a day, expect churn. Worktrees can also eat disk; the FAQ mentions one user who cleared 500 GB and recommends turning on automatic cleanup under Settings → Storage.

Who Should Use It

Good fit:

  • Developers who use two or more agents (say Claude Code and Codex) and are tired of switching apps.
  • Anyone who wants agents running on a beefy desktop or VPS while they steer from a laptop or phone. The FAQ author says fewer than 5% of his prompts run on his laptop.
  • Teams that want to script agents from other agents through MCP.

Poor fit:

  • Local-model users.
  • People who want a single-agent, tightly integrated experience; a provider’s own app will track that provider’s new features first.
  • Locked-down environments where telemetry or a Cloudflare tunnel needs review (LAN pairing and Tailscale avoid the tunnel).

Alternatives

ToolHow it differs
Codex desktop app / Claude DesktopOfficial, single-provider, no open-source server to self-host
Conductor, Cursor GlassNamed in T3 Code’s own FAQ as inspirations that “none met our bar”
Paseo, GooseNamed alongside T3 Code as similar products in an October Hacker News thread
Grok BuildAn agent (harness) rather than a control surface; T3 Code can drive it
Plain terminal + tmux + TailscaleZero new software, but no thread list, diff pane, usage view or phone UI

The meaningful difference is that T3 Code is MIT-licensed end to end, including the server. If the hosted T3 Connect relay ever changes terms, the docs point to Tailscale or self-hosting as the fallback, and there are already community forks.

Community Reactions

In r/PiCodingAgent, a user comparing agent GUIs in October wrote that “t3 seems more polished and less bloated than the other” options, while noting they are not a fan of the founder. Criticism concentrates on the “not a serious tool” line about local models and on the project’s visibility being tied to a large YouTube audience; the Hacker News GitCafe thread drew both curiosity (“Is T3 used widely?”) and skepticism. We found no independent benchmarks.

FAQ

Is T3 Code free?

Yes. It is MIT-licensed and there is no paid tier for the app. You keep paying your agent providers (Anthropic, OpenAI, Cursor, xAI) as before. T3 Connect remote access is free for up to 3 machines; a paid T3 Chat plan raises the machine limit.

Can I use my Claude Code or ChatGPT subscription with T3 Code?

Yes. T3 Code uses the official CLIs and their logins, so claude auth login or codex login on the server machine is enough. The FAQ says this stays within the providers’ terms of service. Note the known issue that Claude usage through the Agent SDK drains 5-hour limits faster than Claude Code used directly.

Does my code go to T3 Code’s servers?

According to the docs, no. Code and prompts go from your machine to your provider. T3 Connect uses a Cloudflare tunnel whose relay sets up the link without proxying sessions. Product usage events (model, token totals, hashed account IDs) are sent unless you set T3CODE_TELEMETRY_ENABLED=false.

How is T3 Code different from Claude Code?

Claude Code is an agent: an interface plus a harness. T3 Code is a front-end and remote control that sits on top of Claude Code, Codex, Cursor and other agents. It does not replace any of them and does nothing without at least one installed.

Bottom Line

If you already run more than one coding agent, or you want agents working on a remote machine while you steer from your phone, T3 Code is the strongest free option available, and the MIT license means you are not locked to its hosted relay. Install it on the machine with your code, change the default permission mode away from Full access, decide on telemetry, and treat it like the 0.1.x software it is.

Sources