spank-claude

Your MacBook has an accelerometer. Claude Code has plugins. You have feelings. Now they can finally meet.

Slap your MacBook (or the desk it sits on) and Claude Code feels it: a face pops up above the prompt, the laptop yelps back in Japanese, and a little counter keeps score of how your day is going. Optionally, Claude itself gets the message — and a hard enough slap stops it mid-turn.

<p> <img src="plugin/assets/faces/sakura/level_1.png" width="96" alt="Sakura, level 1"> <img src="plugin/assets/faces/sakura/level_2.png" width="96" alt="Sakura, level 2"> <img src="plugin/assets/faces/sakura/level_3.png" width="96" alt="Sakura, level 3"> <img src="plugin/assets/faces/sakura/level_4.png" width="96" alt="Sakura, level 4"> <img src="plugin/assets/faces/sakura/level_5.png" width="96" alt="Sakura, level 5"> <br> <img src="plugin/assets/faces/natsu/level_1.png" width="96" alt="Natsu, level 1"> <img src="plugin/assets/faces/natsu/level_2.png" width="96" alt="Natsu, level 2"> <img src="plugin/assets/faces/natsu/level_3.png" width="96" alt="Natsu, level 3"> <img src="plugin/assets/faces/natsu/level_4.png" width="96" alt="Natsu, level 4"> <img src="plugin/assets/faces/natsu/level_5.png" width="96" alt="Natsu, level 5"> <br> <img src="plugin/assets/faces/aki/level_1.png" width="96" alt="Aki, level 1"> <img src="plugin/assets/faces/aki/level_2.png" width="96" alt="Aki, level 2"> <img src="plugin/assets/faces/aki/level_3.png" width="96" alt="Aki, level 3"> <img src="plugin/assets/faces/aki/level_4.png" width="96" alt="Aki, level 4"> <img src="plugin/assets/faces/aki/level_5.png" width="96" alt="Aki, level 5"> </p>

The pain scale

| Level | Hit (at 0.05 g) | Sakura says | Natsu says | Aki says | What probably happened | | ----- | --------------- | ----------- | ----------- | ----------- | ---------------------------------- | | 1 | 0.050–0.106 g | んっ！ | えっ！ | ひゃっ！ | A tap. Passive-aggressive at most. | | 2 | 0.106–0.224 g | あっ！ | うっ！ | あれっ！ | The tests failed again. | | 3 | 0.224–0.473 g | いたっ！ | いてっ！ | いたぁ！ | Claude "simplified" your code. | | 4 | 0.473–1 g | きゃっ！ | やっ！ | いやっ！ | Claude deleted the tests to make them pass. | | 5 | 1 g and up | あぁっ…！ | うわぁっ！ | きゃあっ！ | Production. |

The g ranges are for the default sensitivity, 0.05 g. The scale moves with yours (/slaps calibrate, or "Slap sensitivity" in /config): level 1 starts at your sensitivity, level 5 at 1 g, and the levels between are spread evenly. At 0.15 g, for example, they start at about 0.15, 0.24, 0.39, 0.62 and 1 g.

Two exceptions. Below 0.05 g the scale stays as it is at 0.05 g: softer taps count, as level 1, but a moderate slap doesn't turn into a level 4. Above 0.25 g, level 5 starts at 4 times your sensitivity instead of 1 g, so the levels don't bunch up.

Combos

Keep slapping, less than a second apart, and every tap counts, however soft: each is one level above the one before, or its own level if it hit harder, and the level never drops until you pause. Five soft taps make her scream. A harder slap cuts her off with its own yelp; one at the same level does too, but stays quiet if her last yelp is under 0.4 s old, so drumming doesn't stutter. The face says how many came in a row, and a combo puts up one toast as it starts and one as it ends, saying how far it got. The score (/slaps, the status line) still keeps what the sensor read.

Taps can come as fast as about 7 a second. A hard slap leaves the laptop ringing, so the next tap counts once that has died down, usually within a fraction of a second.

What you need

• An Apple Silicon MacBook with the motion sensor: M1 Pro / Max or newer. The plain 2020 M1 13" reportedly has no readable sensor. A Mac mini will feel nothing, no matter how hard you hit it. Please don't test this.
• macOS 27. It reads the sensor without sudo there; older releases may want root (untested).
• Xcode Command Line Tools (xcode-select --install). The plugin builds its little sensor reader from Swift source on first run, so nothing precompiled ships in the repo.
• Claude Code with plugin function hooks (built and tested on 2.1.288; that API is early access and may move).

Install

Two commands, no cloning:

claude plugin marketplace add slima4/spank-claude
claude plugin install spank@spank-claude

(or the same from inside Claude Code: /plugin marketplace add slima4/spank-claude, then /plugin install spank@spank-claude.)

Start Claude Code. The first session builds the sensor reader (the status line says spank: building the sensor reader, about 20 seconds), then shows spank: armed (0.05g). Go on. Slap it.

Updates: claude plugin update spank@spank-claude, then restart Claude Code. Each new version builds its sensor reader again on its first start. Uninstall: claude plugin uninstall spank@spank-claude.

Commands

| Command | Does | | -------------------- | ----------------------------------------------------------- | | /slaps | Your score: this session, all time, and the last hit. | | /slaps who | Lists the face series; the current one is marked. | | /slaps who natsu | Natsu gets slapped now (any series name works). | | /slaps calibrate | Type 6 s (no Enter), knock 3 times; it picks the sensitivity. | | /slaps mute | Silences her. The faces still judge you. | | /slaps unmute | She's back. | | /slaps claude on | Slaps reach Claude; a level 4+ slap or combo stops its turn. | | /slaps claude off | Claude stays blissfully unaware (the default). | | /slaps image | Checks whether your terminal can show real pictures. |

Claude mode

With /slaps claude on, every slap becomes a quiet note in the conversation: "The user just physically slapped their laptop 2 times (accelerometer; strongest hit level 3 of 5, 0.31g). Take it as nonverbal frustration…" Claude reads it on its next step, acknowledges it, and reconsiders what it was doing. Slaps that keep coming are told as one note once you pause, or 4 seconds after the first, whichever comes sooner. Slaps while it's idle are saved up and delivered as one note with your next message, so it gets the whole story at once.

A level 4+ slap while Claude is working stops the turn on the spot (the level is a setting). So does a combo that builds up to it and lasts at least half a second (so one slap that bounces doesn't), unless one of its slaps was a level 1 graze (so the steady shaking of a bumpy train doesn't). Fair warning: a shell command Claude already started keeps running in the background; the slap stops Claude, not the command.

Several sessions

Only the Claude Code session you used last reacts to a slap (the one you last typed a prompt or a /slaps command in). One laptop, one victim.

Face series

Each face series is one character: five faces, one per level, and a voice. Switch with /slaps who <series> (/slaps who lists them), or under "Face series" in /config.

| Series | Voice | Face | | -------- | -------- | ------------------------------------------------------------- | | sakura | sakura | <img src="plugin/assets/faces/sakura/level_1.png" width="48" alt="Sakura"> | | natsu | natsu | <img src="plugin/assets/faces/natsu/level_1.png" width="48" alt="Natsu"> | | aki | aki | <img src="plugin/assets/faces/aki/level_1.png" width="48" alt="Aki"> |

Faces and terminals

Faces are drawn as colored half-block characters, so they show up in any truecolor terminal (Warp, iTerm2, Ghostty, …), pixel-art style, in the biggest size that fits above your prompt.

Real, full-resolution pictures need a terminal with kitty graphics Unicode placeholders, which today means Ghostty or kitty. Run /slaps image to see what yours can do. Warp and Terminal.app currently can't (not our fault, we checked).

Settings

Open /config in Claude Code (or /plugin configure spank@spank-claude):

| Setting | Default | What it does | | ----------------------- | ------- | --------------------------------------------------------- | | Slap sensitivity (g) | 0.05 | Smallest shake that counts, and where level 1 starts. Typing counts? Raise it. | | Level that stops Claude | 4 | With /slaps claude on, this level or harder stops a turn. | | Face series | sakura | sakura, natsu or aki: whose face pops up and voice yelps. | | Face size | large | large (24 rows), medium (16), small (12), or off. | | Voice volume | 1 | 0 is silent, up to 4 for open-plan offices. |

Changes apply right away. Not sure what sensitivity to pick? Run /slaps calibrate: type anything for 6 seconds (don't press Enter, or Claude gets it), then knock on the desk 3 times, and it sets the sensitivity between the two for you. The 6 seconds start at your first key and the knocking at your first knock, so take your time reading; it waits up to 30 seconds for each. The status line then shows it, e.g. spank: armed (0.077g).

How it works

 MacBook IMU (AppleSPUHIDDevice, ~1 kHz)
      │  IOKit HID reports, x/y/z in 1/65536 g
      ▼
 slapd (Swift) ── removes gravity, finds the peak
      │  {"type":"slap","ts":…,"peak":0.42} on stdout
      ▼
 spank plugin (Claude Code hooks) ── grades it 1–5 for your sensitivity
      ├─ status line + toast
      ├─ face above the prompt (Raster cells, 3 s)
      ├─ voice clip per level
      └─ optional: note to Claude / stop its turn

Development

Run straight from a clone (uninstall the marketplace copy first, or you get two of her):

git clone https://github.com/slima4/spank-claude && cd spank-claude
claude --plugin-dir "$PWD/plugin"

make slapd                         # build the sensor reader by hand
make raw                           # watch the live shake
make faces                         # rebuild face cells from assets/faces/<series>/*.png
claude plugin validate .           # the marketplace and the plugin
claude plugin test plugin          # the tests

Installed copies are kept per version, so bump version in plugin/.claude-plugin/plugin.json when you ship a change.

To add a face series, say hana:

1. Put its faces in assets/faces/hana/level_<1-5>.png (square, on white).
2. Add "hana" to the face_series options in plugin/.claude-plugin/plugin.json.
3. Run make faces. It draws the cells into plugin/hooks/faces.ts, writes the 256px pictures to plugin/assets/faces/hana/, and warns if step 2 is missing.
4. In plugin/hooks/series.ts, add hana to SERIES. It can borrow an existing voice (voice: 'sakura'), or get its own: clips in plugin/assets/voices/hana/level_<1-5>.mp3 and their captions in VOICES.

License

MIT. Slap responsibly.

Safety notes

• It's a laptop, not a punching bag. AppleCare does not cover "it was for a plugin."
• Level 5 is reachable with a firm palm. You don't need to prove anything.
• The sensor reading comes from the community's reverse-engineering work in olvvier/apple-silicon-accelerometer and taigrr/apple-silicon-accelerometer.