About this mod

🎃 Halloween for Claude Code

A Halloween theme for the Claude Code terminal.

• A haunted frame around the prompt. Bats, leaves and a moon perch on a violet edge above the prompt. Below it runs a moss vine where jack-o'-lanterns grow in random clumps and flicker their glow onto the vine. A ghost drifts along the top every so often, trailing ectoplasm. Every session gets its own random layout.
• Bats across the conversation. A small flock flies whole journeys over your chat: in from one side and out the other, rising or falling along a gentle arc, some cruising and some darting.
• Spooky words. The spinner says things like Brewing…, Summoning… or Stirring the cauldron…, and finished turns read Haunted for 12s.
• Spooky sounds, if you dare. Each keystroke squeaks like a bat or, now and then, cracks like lightning. Enter answers with a villain's mwah-ha-ha, a witch's cackle, a demon's laugh, a wailing ghost, a pipe organ or a thunderclap. Every Enter sound plays once before any repeats, and the same one never plays twice in a row. Sounds are off until you turn them on.

Install

In Claude Code:

/plugin marketplace add phuclh/claude-halloween
/plugin install halloween@phuclh-plugins

Or from a shell:

claude plugin marketplace add phuclh/claude-halloween
claude plugin install halloween@phuclh-plugins

Then start a new session.

Use

• /halloween turns the theme off and on. Your choice is remembered across sessions.
• /halloween sounds turns the sounds on and off, and is remembered too. Sounds play on macOS only: Claude Code plays them with afplay, and plays nothing on Linux or Windows.
• After 90 seconds with no typing and no work from Claude, the animation pauses and stops using CPU. It wakes as soon as you type or Claude starts working.

Requirements

• Fullscreen mode for the frame and the bats: set "tui": "fullscreen" in ~/.claude/settings.json, or switch with /tui. On other screens you get the spooky words and a small garland on the hint line.
• A recent Claude Code. The theme uses Claude Code's early-access function-hook API, which may change between releases. Built and tested on Claude Code 2.1.287.

Performance

While animating, the theme redraws the screen 8 times a second, which costs about 8–11% of one CPU core on a 110×40 terminal. Once paused, it costs nothing.

With sounds on, each keystroke starts a short afplay, at most one every 70 ms. That adds about 0.02 s of CPU per keystroke, and only while you type.

Develop

claude --plugin-dir ./plugins/halloween       # run it from this folder
claude plugin validate ./plugins/halloween    # check the manifest and hooks
claude plugin test ./plugins/halloween        # run the tests

The demo above is drawn by the plugin's own frame and flight code. To render it again after a change:

npx -p typescript tsc -p scripts
node .demo-build/scripts/render-demo.js > assets/demo.svg

The sounds are synthesized from oscillators, noise and filters by scripts/render-sounds.ts; the laughs come from a small formant synthesizer. Nothing is recorded or sampled. To render them again into plugins/halloween/sounds/:

npx -p typescript tsc -p scripts
node .demo-build/scripts/render-sounds.js