byre is open source on GitHub -- pjlsergeant/byre
byre

Quickstart

cd ~/my-project
byre develop

The first byre develop in a project asks a few quick questions and remembers your answers:

  • Template – the stack the box is built for (go, node, python, or one of your own). It decides the base tooling and cache volumes.
  • Agent – which coding agent launches in the box (Claude Code, Codex, Gemini, Grok, OpenCode).
  • Shared login – for agents that support it, whether this box uses your machine-wide credentials instead of a per-project login (see How do I…?).

Your favourites become the pre-selected defaults, so the second project’s picker is a couple of Enters. Log the agent in once; the login persists, per project, across rebuilds. To skip the questions entirely:

byre develop --template go --agent claude

byre generates a Dockerfile from your config, builds it (only on a cache-miss – relaunches are fast), and drops you into the agent in the foreground. Exit the agent and the session ends; run byre develop again and /resume to pick up where you left off.

Ask the box what it can touch, any time:

$ byre status
Project id:   my-project-pjl-069d95
Agent:        byre/claude
Template:     byre/go      bundled v1.3.1
Engine:       docker
Project:      ~/my-project -> /workspace  (rw)
Image:        byre-my-project-pjl-069d95-u501-g20  (sha256:1f0b7c9d4e2a…
              (--full to show); base golang:1.26-bookworm)
Network:      open
Ports:        none
Host mounts:  none
Skills:       byre/claude  bundled v1.3.1
State vols:   .claude
Cache vols:   none
Box env:      10 keys the box received  (values never recorded; --full to show)
Container:    running (0d95f3a2c1b4)
              ↳ the grant rows above describe THIS box (launch record
              4c1e8a7b2d90). Other rows describe the current config.

Every row that exists is on that page – long values are cut down and each cut says so. byre status --full shows them whole; byre status --data prints the same content as JSON.

From here: configuration to widen or narrow the box, worktrees for parallel sessions, and what’s boxed, what isn’t for the contract you just signed.