mc-agent-oof

mc-agent-oof

Plays Minecraft sounds when Claude's commands fail.

what it does

Every Bash tool call goes through a PostToolUse hook. Exit code + stderr decide which sound plays:

tier	when	sound
hurt	lint fail, test fail, generic non-zero exit	the iconic player "oof"
explode	build / compile error, missing module, syntax error	TNT
anvil	segfault, panic, core dump, OOM	anvil drop
levelup	a previously-failing command finally goes green	the "ding"
nothing	success without a prior failure	—

Real Minecraft sounds. Pulled on first run from Mojang's CDN (resources.download.minecraft.net) and cached at ~/.cache/mc-agent-oof/sounds/. Nothing audio is checked in.

install (claude code)

git clone https://github.com/trevorstenson/mc-agent-oof
cd mc-agent-oof
claude

In Claude:

/plugin marketplace add ./
/plugin install mc-agent-oof@mc-agent-oof

Restart Claude. Run /hooks and confirm you see PostToolUse → Bash → mc-agent-oof/posttooluse-bash.sh. Done.

use without claude

bin/mc-agent-oof npm test
bin/mc-agent-oof cargo build --release
bin/mc-agent-oof sh -c './configure && make'

Same classifier, runs locally on whatever command you pass. stdin/stdout/stderr pass straight through. Symlink it onto your PATH if you want it everywhere:

ln -s "$(pwd)/bin/mc-agent-oof" ~/.local/bin/mc-agent-oof

test the sounds

python3 plugins/mc-agent-oof/scripts/fetch_sounds.py
python3 plugins/mc-agent-oof/scripts/test_sounds.py hurt explode anvil levelup

requirements

• Python 3.10+
• An audio player. macOS has afplay. Linux: install paplay, ffplay, or mpv. (aplay doesn't decode .ogg.)
• Internet on first run (~140 KB of sounds, downloaded once).

If anything's missing, classification still runs. You just won't hear it.

custom sounds

MC_AGENT_OOF_SOUNDS=/path/to/dir overrides the cache. File names matching the tier prefix work:

hurt1.ogg, hurt2.ogg, hurt3.ogg     → hurt
explode1.ogg, explode2.ogg, ...      → explode
anvil_land.ogg                       → anvil
levelup.ogg                          → levelup

how it classifies

First match wins, top to bottom:

stderr or exit	tier
Segmentation fault, panicked at, OutOfMemoryError, SIGSEGV, Aborted	anvil
exit 134 / 138 / 139	anvil
error:, error TS\d+, error[E\d+], FAILED, fatal:, cannot find module	explode
any other non-zero exit	hurt
exit 0 with prior failure (same cwd + tool)	levelup
exit 0, no prior failure	silence

Heuristic. If a test asserts on the literal string "Segmentation fault" you'll get an anvil. Whatever, it's a sound effect, not a verdict.

levelup is gated on the command's first word being build-ish: make, cargo, npm, pnpm, yarn, bun, go, gradle, mvn, pytest, jest, vitest, tsc, eslint, python3, etc. State is keyed by cwd + first word, so npm test and npm install share state.

limitations

• Claude Code only. Codex and Cursor don't expose a PostToolUse-equivalent hook.
• macOS / Linux. Windows: PRs welcome.
• Wrapper uses bash process substitution, not POSIX sh.

license

MIT for the code. The sound files belong to Mojang/Microsoft and download from their CDN at runtime — not redistributed here.