Multi-Agent Guide

T3 Code

Orchestrator · Last verified 2026-09-30

TL;DR

T3 Code is an MIT-licensed control surface from T3 Tools for coding agents installed on your machine, with Electron desktop, web, iOS and Android clients. Each thread can run in its own git worktree, and one prompt can fan out to several models. It suits developers who want a GUI over Claude Code, Codex or OpenCode.

Key facts

T3 Code key facts. Data as of 2026-09-30.
Type Orchestrator
Languages / SDKs TypeScript
License MIT
Pricing model Open source, free
Orchestration pattern Other
GitHub stars 23,963 (as of 2026-09-30)
GitHub forks 6,266
Last push 2026-09-30
Latest release v0.0.44
Repository pingdotgg/t3code
Website t3.codes
Documentation github.com
Last verified 2026-09-30

Key features

  • Controls agents already installed and logged in on your machine: Codex, Claude Code, Cursor, Grok Build, OpenCode and Google Antigravity, using your own subscriptions. (source)
  • Each thread is a separate task; choosing New worktree gives its code changes a separate branch and working directory, and background threads each get their own worktree. (source)
  • Shift-click several models in a new thread's picker to send one prompt to each; every selection starts its own thread and worktree. (source)
  • Four permission modes (Supervised, Auto-accept edits, Auto, Full access) decide when an agent needs approval, set per thread. (source)
  • Git actions on a thread commit, push and create pull requests; a Pull requests page reviews, checks out and merges on GitHub, GitLab and Azure DevOps. (source)
  • A phone, browser or second desktop can connect to T3 Code running on another machine through T3 Connect or a pairing URL. (source)
  • Rules can remove T3-managed worktrees after inactivity, after merge, or with their thread. (source)

Architecture and orchestration pattern

Pattern: Other

T3 Code has a server process (started with t3, t3 serve or by the desktop app) and several clients: an Electron desktop app, a web app and mobile apps. The server drives provider agents on the machine that holds the code, so a phone or browser is a remote control for a machine that stays running. Providers are installed and authenticated on that machine; T3 Code does not add its own model access.

Work is organized as projects containing threads. A thread is one conversation with one provider and model, running in the project directory or in a git worktree that T3 Code creates. Parallel work is manual: the user starts threads, or shift-selects several models to fan one prompt into several threads. No planner that assigns work between agents is documented.

The server also contains an MCP HTTP server in apps/server/src/mcp/ with toolkits for browser preview automation, pull requests and device screenshots. State (projects, threads, settings) lives under ~/.t3/userdata on the host.

Human in the loop

Permission modes give per-thread control: Supervised asks before commands and file changes, Auto-accept edits approves edits only, Auto uses the provider's automatic review where one exists, and Full access removes prompts. The docs say the initial default is Full access. Approvals and rejections happen in the conversation, and pull requests are reviewed and merged from the Pull requests page. Agents can still ask questions in any mode.

Harnesses it can drive

Protocols

MCP, A2A and AG-UI support for T3 Code. See the full matrix.
ProtocolSupportNote
MCP Yes evidence
checked 2026-09-30		 The server source implements an MCP HTTP server (McpServer from effect/unstable/ai) with preview automation, pull request and device toolkits. Server side; found in code, not in a user-facing docs page.
A2A Unknown
checked 2026-09-30		 Searched the README, docs/user pages, file names and GitHub code search for 'a2a'; nothing found.
AG-UI Unknown
checked 2026-09-30		 Searched the README, docs/user pages and file names for 'ag-ui'; nothing found.

Best for

  • Running Claude Code, Codex or OpenCode threads in separate git worktrees from a desktop, web or phone client. (shortlist)
  • Sending the same prompt to several models at once and comparing the resulting worktrees. (shortlist)
  • Driving agents on a home or cloud machine from a phone through T3 Connect or a pairing URL. (shortlist)
  • Committing, opening and merging pull requests from the same window as the agent thread. (shortlist)

Not for

  • Users who need a stable, mature product: the README says the project is very early and to expect bugs.
  • Contributors hoping to land large features: the README says big features are mostly not accepted yet.
  • Automated agent-to-agent delegation; the docs describe manual threads, not a coordinating agent.

Quickstart

curl -fsSL https://t3.codes/install.sh | sh

Install not yet verified by this site. What this means 

# Prerequisite: install and log in to at least one provider, e.g.
#   codex login   |   claude auth login   |   opencode auth login
curl -fsSL https://t3.codes/install.sh | sh
t3                      # start the server and open the local web app
t3 service install      # keep it running in the background
t3 update               # move to a newer release

# Desktop app and terminal helper
brew install --cask t3-code
t3 app ../my-project    # open a new thread for a directory in the running desktop app

# Reach it from a phone or another machine
t3 connect              # sign in to T3 Connect
t3 serve                # start the server if you declined the background service

Common pitfalls

  • Install and authenticate at least one provider on the machine first; T3 Code only controls agents that already work there.
  • The initial permission default is Full access; change it under Settings > General > New threads > Permissions.
  • t3 app needs the desktop app running on the same machine; it does not work against a standalone server or over SSH.
  • Signing in to T3 Connect alone does not make a machine reachable; the server must be running (t3 serve or the background service).
  • The .deb desktop build asks for your password to install each update.
  • Product usage events go to PostHog unless T3CODE_TELEMETRY_ENABLED=false is set in the server environment.

Official quickstart

Pros

  • Works with the subscriptions and CLIs already set up on the machine, so no separate model access is needed. (source)
  • Worktree-per-thread isolation, including one worktree per model when fanning a prompt out. (source)
  • Clients on desktop, web, iOS and Android, with remote access to a host machine. (source)
  • Per-thread permission modes and built-in pull request review and merge. (source)
  • MIT licensed; the README says the goal is that you can fork it if the direction changes. (source)

Cons

  • The README says the project is very early and to expect bugs; releases are still 0.0.x. (source)
  • The default permission mode is Full access, so agents can run commands and edit files without approval until you change it. (source)
  • Product usage events (provider, model, permission mode, turn result, token totals) go to PostHog unless telemetry is disabled with an environment variable. (source)
  • Contributions are mostly not accepted yet, and the docs have no dedicated site. (source)
  • Parallel work is manual and per-thread; no coordinator agent or task graph is documented. (source)

Alternatives

FAQ

Does T3 Code support MCP?

Yes, on the server side: the source contains an MCP HTTP server with browser preview, pull request and device toolkits. The user docs I read do not describe it, so the evidence is the code file.

Is T3 Code free?

Yes. It is MIT licensed and the README says nothing is being sold. You pay your own providers, since it controls agents that run on your machine with your subscriptions.

Which agents does it run?

Codex, Claude Code, Cursor, Grok Build, OpenCode and Google Antigravity. Hermes and OpenClaw are not listed.

Does each thread get its own worktree?

Only if you choose New worktree; background threads started from the composer then each create their own worktree. Otherwise a thread works in the project directory.

What platforms does it run on?

The desktop app installs through winget, Homebrew, a .deb package or the AUR, so Windows, macOS and Linux; iOS and Android apps connect to a server on another machine.

Sources

Unknown fields: protocols.a2a and protocols.agui: nothing found in README, docs/user pages, file names or code search. MCP evidence is a source file, not a docs page. Pricing of T3 Connect (hosted relay account) and the hosted web app at app.t3.codes is not stated in the docs read; the record uses oss-free because the README says nothing is being sold.

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