kaboom.claude 😈

Real Freedoom, playable right next to Claude Code — in one command. npx kaboom.claude opens a split: Claude on the left, the game on the right. The game starts the moment Claude begins working and waits when you switch back to read the reply — so you frag demons in the dead time and never miss Claude's answer. No install, no WAD hunting, no compiler: the real doomgeneric engine runs as WebAssembly and the free, BSD-licensed game data ships in the package.

Play

From a normal terminal (needs tmux; Linux/macOS/WSL):

npx kaboom.claude

That's it — Claude and the game open side by side, each pane labelled (◀ CLAUDE / GAME ▶) with the focused pane outlined in bright green so it's always clear which one has your keys.

• Auto-starts on Claude's turn. The moment you send a prompt and Claude starts working, the game comes into focus and plays — hands-free. (It focuses the pane; it does not zoom you to fullscreen — that stays your call.)
• Hands you back when Claude replies. By default, the moment Claude finishes the game pauses and focus returns to Claude so you never miss the answer — play the wait, then you're right back where you need to be.
• Don't want the interruption? Click Don't interrupt in the bottom bar. Now when Claude replies the game keeps playing and just shows a 🔔 note; go read the reply whenever you like (Alt-← or click the left pane). Click it again to go back to auto-return.
• Switch panes: click a pane, the ◀ Claude / Game ▶ buttons in the bottom bar, or Alt-←/→. The green outline moves with you.
• Resize the split: drag the divider with your mouse, or nudge it with Alt-Shift-←/→ (hold to slide it) — give the game more room, or hand it back to Claude, however you like.
• Minimize: the ›› button shrinks the game to a thin sliver at the edge and drops you into Claude. Click the sliver (it shows ‹‹) to bring the game back to its previous size — the strip itself is the restore button, right there at the divider.
• Zoom: the ⤢ Zoom button (or Alt-z) blows the game up to fullscreen for real playing; press again to return.
• Close the game: the ✕ Close game button (or Q) closes the game only — Claude keeps running. The button then becomes ✕ Close Claude, which ends the whole split.

Controls

| Action | Keys | |---|---| | Move / turn | W A S D or arrow keys | | Fire | Space or F | | Use (doors, switches) | E | | Run | hold Shift while moving | | Weapons | 1–7 | | Automap | Tab | | Menu | Esc | | Quit the game | Q |

Runs on its own tmux socket, so your normal tmux config is untouched. Remove the pause hooks any time with npx kaboom.claude unhook.

No tmux? Play full-screen

npx kaboom.claude play

Runs just the game, full-screen, on its own — no Claude split, no tmux.

How it renders (and why it's readable)

kaboom picks the best renderer your terminal supports, automatically:

• Sixel (crisp, the good one). When the terminal advertises Sixel, kaboom draws the framebuffer as real pixels — so menus, options and scores are pixel-sharp, exactly like the "very clear" terminal-Doom projects. Doom only uses ≤256 colours per frame, so each frame is encoded losslessly (no quantization) and drawn inside synchronized-output brackets to avoid tearing. The picture renders at Doom's native ~640×480, and in the split the game pane auto-fits to it so Claude gets all the leftover width (no black margins). This is auto-detected via the terminal's device-attributes reply; through tmux it needs a tmux built with --enable-sixel (tmux ≥3.4) and a Sixel-capable host terminal (Windows Terminal ≥1.22, WezTerm, xterm, foot, mlterm, …).
• Block fallback (everywhere else). Without Sixel, kaboom falls back to sextant blocks — a 2×3 grid of sub-pixels per character cell (Unicode U+1FB00…), with each cell's foreground/background split by colour clustering (not brightness), so red-on-red menu text still separates instead of turning to mush. Frame-diffing redraws only changed cells. Readable, if not pixel-perfect.

Either way it's 24-bit truecolor, fit to your terminal; press Alt-z (⤢ Zoom) for the sharpest picture.

Knobs: KABOOM_SIXEL=0 forces the block renderer even where Sixel is available (and =1 forces Sixel on); KABOOM_BLOCKS=quad uses 2×2 quadrant blocks (for fonts without sextant glyphs).

Keyboard note: on terminals with the Kitty keyboard protocol (Kitty, Ghostty, WezTerm) controls use real key press/release for crisp strafe/run; elsewhere they fall back to autorepeat.

How it works

• The engine is doomgeneric compiled to WebAssembly — it runs under plain Node, no native modules, no system packages. (The WASM build is vendored from pi-doom.)
• Play/pause is driven by Claude's activity. npx kaboom.claude installs small Claude Code hooks (UserPromptSubmit → busy, Stop → idle, plus subagent/tool/notification hooks) that write per-session files the game watches. The game plays while Claude is busy and freezes when you return to read. All hooks are guarded on a KABOOM_ID env var, so they do nothing in any Claude session that isn't a kaboom split.
• A live Claude info panel sits in the empty top-right space above the game: Claude's state (working / replied / needs-you), model, a context-fill bar, tokens, running subagents, current tool, cost and turn count — plus the 🔔 bell. The telemetry comes from a statusLine command kaboom installs non-destructively: it wraps and passes through your existing status line, and npx kaboom.claude unhook restores it exactly.
• Switching is beginner-proof. Everything (mouse, Alt-keys, the status-bar buttons, the green focus outline) runs on a dedicated tmux socket, so none of your own tmux config is touched.
• The game data is Freedoom Phase 1 (freedoom1.wad) — a free, BSD-3-Clause IWAD with no id Software assets. Bundled, so there's nothing to fetch.

Requirements

• Node.js ≥ 16 (WebAssembly support).
• tmux for the split (Linux / macOS / WSL). Full-screen play mode doesn't need it. For the crisp Sixel picture in the split, tmux must be built with --enable-sixel (tmux ≥3.4) — otherwise it falls back to blocks.
• A truecolor terminal. For pixel-sharp text, a Sixel-capable one (Windows Terminal ≥1.22, WezTerm, xterm, foot, mlterm…); otherwise any terminal with a sextant-capable font works via the block fallback.

Credits & license

• Freedoom — the free, BSD-licensed game data (freedoom1.wad). © 2001–2024 the Freedoom contributors (see engine/FREEDOOM-CREDITS.txt).
• doomgeneric — the portable Doom engine port (from id Software's GPL engine release).
• pi-doom — the Node/WASM build this vendors.

Code: GPL-2.0-or-later (full text in COPYING). Game data (Freedoom): BSD-3-Clause. See LICENSE for full attributions, the GPL corresponding-source offer, and modification notes. The bundled engine/doom.js + engine/doom.wasm are an unmodified WebAssembly build of doomgeneric (via pi-doom); complete corresponding source is at those upstream repos.

This project ships no id Software assets. DOOM is a trademark of id Software; Claude and Claude Code are trademarks of Anthropic. This is an independent, unofficial tool, not affiliated with or endorsed by id Software, the Freedoom project, or Anthropic.