lowfat is a lightweight CLI tool that reduces AI token costs by filtering unnecessary CLI output before it reaches your agent.

Core focus

• Lightweight — Small single binary, small core; but extensible.
• Local-first — No telemetry; you own your data.
• Composable — UNIX-style pipes, mix built-ins and your own filters; not magic.
• User-owned — lowfat history shows what you run most; allow you to customize for your usecase.

Token savings on real commands

Command	Raw	Filtered	Saved
git status	115t	5t	96%
git diff	2,376t	115t	95%
git log	379t	118t	69%
docker ps	271t	41t	85%
ls -la	192t	30t	84%

Install

cargo install lowfat
# or
brew install zdk/tools/lowfat

Pre-built binaries on GitHub Releases.

Setup

Pick one of:

Claude Code hook — add to .claude/settings.json:

{
  "hooks": {
    "PreToolUse": [
      { "matcher": "Bash", "hooks": [{ "type": "command", "command": "lowfat hook" }] }
    ]
  }
}

Shell integration — auto-activates inside agent environments (CLAUDECODE=1, CODEX_ENV):

echo 'eval "$(lowfat shell-init zsh)"' >> ~/.zshrc   # or ~/.bashrc

Direct usage — prefix any command:

lowfat git status
lowfat docker ps
lowfat ls -la

pi agent — in ~/.pi/agent/settings.json:

{ "shellCommandPrefix": "eval \"$(lowfat shell-init zsh)\"; " }

Usage highlights

# See what's configured and how loud each filter is being
lowfat info                       # status badge + active filters
lowfat info git                   # pipeline for `git`
lowfat info --config              # full resolved config

# See what lowfat has saved you
lowfat stats                      # lifetime token savings
lowfat stats --audit              # recent plugin executions
lowfat history                    # rank commands by potential savings

# Dial the aggressiveness
lowfat level ultra                # max compression
LOWFAT_LEVEL=lite lowfat git log  # one-off override

# Write a plugin
lowfat plugin new terraform       # scaffold ~/.lowfat/plugins/terraform/
lowfat plugin doctor              # check plugins (and pre-install any Python deps)

# Test a plugin against a sample without installing it
cat samples/git-diff-full.txt | lowfat filter --explain ./filter.lf --sub=diff --level=ultra

Learn more

• docs/CONFIG.md — .lowfat file, env vars, pipeline DSL, built-in processors, the history ranking
• docs/PLUGINS.md — .lf rule DSL, shell escape hatches, PEP 723 + uv, AI agent prompt

Alternatives

• rtk
• context-mode
• lean-ctx
• tokf
• tamp
• ecotokens
• token-enhancer

License

Apache-2.0

AI notice

Multiple AI tools were used for this project