tau code

Run a τ agent inside VS Code or VSCodium.

τ is a Python agent harness. This extension is a client for it: it starts tau --mode rpc as a child process and talks to it over τ's documented JSON-RPC protocol. The agent's tools run against the folder you have open.

Status: scaffold. Chat works end to end, with Tab completion for /commands and @files. The conversation tree browser and the editor integrations are designed for but not built. The list at the bottom of this page says what is missing, so you find out here rather than after installing.

Requirements

τ has to be installed and its tau console script reachable:

pipx install ffwf-tau        # or: pip install ffwf-tau

τ needs a model. It reads ~/.tau/config.json; run tau once and it writes a template you can edit.

If tau is not on your PATH, set tau-code.binary to the full path.

Use it

1. Open the folder you want the agent to work in. The extension refuses to start without one, because there is no honest working directory for the agent's tools otherwise.
2. Click the τ icon in the activity bar, or press Ctrl+Alt+T (Cmd+Alt+T on macOS).
3. Pick a session to continue, or press Start here to use the new one.
4. Type. Ctrl+Alt+T again opens the same session as a full editor tab.

The panel opens on the session list whenever the session it started is empty. tau writes a session to its store when the agent starts rather than when you first send something, so opening the panel four times leaves four empty sessions; landing on the list means the obvious next click is a conversation you were already having.

Three commands are in the palette under tau: Open Agent, Restart Agent, Show Agent Log.

Tab completion

/ lists τ's commands, @ lists files. Tab opens the list and writes the first candidate straight into the editor; Tab again cycles, Shift+Tab goes back. There is no separate accept key, so the editor always holds exactly what will be sent.

The file list comes from τ, not from the editor. That matters over Remote SSH or in a devcontainer: τ answers from the directory its own tools resolve against, which is where your code actually is.

@file completion needs τ at protocol 1.4 or later. Everything else works against 1.3, and the composer says which one you have rather than failing.

How answers render

The model's replies are rendered as Markdown — headings, lists, tables, links, and fenced code in the editor's own font. Your own messages are not: what you typed is shown as the characters you typed, so a * in a filename stays a * and the attachment block tau built from an @file stays visible.

Code is not syntax-highlighted. VS Code publishes theme variables for editor chrome but not for token colours, so any palette shipped here would be our colours sitting inside your theme.

Settings

tau-code.sessionDir is worth reading about. Empty uses τ's default for RPC hosts: a private <tmp>/.tau-<uid>/sessions, so this extension does not fill the session list you see in τ's own TUI — and those sessions do not survive a reboot on a system that clears its temp directory. Set it to ~/.tau/sessions to share one store. Resume then works both ways: the picker here lists sessions the TUI wrote, and tau --continue resumes ones written here.

Remote development

The extension declares extensionKind: ["workspace"]. Over SSH, in WSL, or in a devcontainer the agent runs where the code is while the panel renders locally. That split is the one thing a standalone web client cannot reproduce.

What is deliberately missing

• The conversation tree browser. τ's differentiator, and the reason this project exists. It needs tree verbs on the wire; τ has none today.
• /tree and /extensions. τ resolves both and expects the client to perform them. This one does not, so it says so. They appear greyed in the completion popup.
• Renaming a session. The picker lists, switches, forks and starts.
• Removing an attachment by clicking it. The @word in the text is the only handle: delete it.
• Jump-to-edit and diff views. τ's tools compute the data and the agent loop discards it before a message is built.
• Live tool arguments. During a call you see the tool's name and that it is running. The arguments arrive at turn end.

If the panel says it could not register a service worker

That error is VS Code's, not this extension's, and it is known upstream since 2021. Chromium fails to register the service worker VS Code puts behind every webview, and every webview in the window then fails to load — Markdown preview and the Jupyter panes as well as this one. It happens most often with a second editor already running, which is why installing in VS Code and VSCodium side by side finds it.

Run Developer: Reload Window. There is no port to change and nothing to configure: the panel is a vscode-webview:// document talking over postMessage, and this extension opens no socket of any kind.

About

tau code is built by FFwF Robotics — Fight Fire with Fire Robotics — whose stated business is loyal automatons for the inevitable machine uprising. Three projects, usable separately or as one stack: Tectum, an event substrate orchestrated with schema documents; Tau, the agent harness this extension is a client for; and JMFTS, a retrieval appliance that fuses Matryoshka embeddings, ColBERT late interaction and BM25 into one hybrid search on Postgres. The documentation for all three is at ffwfrobotics.github.io.

FFwF is John McCardle: a masters in Cyberintelligence from the University of South Florida, author of McRogueFace, a portable Python/C++ game engine, founder of the Bespoke Robot Society, and president of Kennedy Space Center's amateur radio club.

Source

https://github.com/jmccardle/tau-code. The container and the standalone web client are built from the same packages and live there too.

MIT licensed.