Subspace

Review Markdown without leaving your terminal.

Subspace gives Claude Code and Codex a focused reader where you can attach comments and suggested changes to exact text. When you finish, your decision and feedback return to the agent that asked for the review.

Try it in your terminal

Install the native app with Homebrew:

brew install spacedock-dev/tap/subspace-beta

Open any Markdown file:

subspace-tui path/to/file.md

Select text to leave a comment or suggest a replacement. When you are ready, approve the document, request revisions, or leave the review open for later.

Use it with Claude Code or Codex

The agent integration supports Zellij 0.44.x, tmux 3.2 or newer, Herdr 0.6.5, CMUX 0.64.20 build 100, Ghostty 1.2 or newer on macOS, and the system Apple Terminal. It also requires jq and the Homebrew-installed subspace-tui binary above.

Choose one agent host and install the Subspace plugin.

For Claude Code:

claude plugin marketplace add spacedock-dev/marketplace
claude plugin install subspace@spacedock

For Codex:

codex plugin marketplace add spacedock-dev/marketplace
codex plugin add subspace@spacedock

Start a new agent session so the plugin loads, then ask it to review a file:

# Claude Code
/subspace:r docs/design.md

# Codex
$subspace:r docs/design.md

Pass a terminal explicitly, such as $subspace:r docs/design.md tmux, or omit it to detect the current supported terminal.

Subspace opens the file in the terminal. Your comments, suggestions, and final decision return to the same agent session when you submit the review.

Troubleshooting

The current plugin requires subspace-tui version 0.10.0-beta.2.

If the binary is missing:

brew install spacedock-dev/tap/subspace-beta

If an older version is installed:

brew upgrade spacedock-dev/tap/subspace-beta

If Homebrew is not installed, follow the instructions at brew.sh, then retry the appropriate command above.

License

Apache-2.0 covers the public plugin and skill integration files in this repository. The released subspace-tui binary is proprietary, and its source code is not included.