Open source · MIT · Claude Code CLI

Claude Code Lean

Less context. Same coding power.

One command. Four profiles from most stripped to fully custom. Keep OAuth — no API key required.

One-command install
curl -fsSL https://raw.githubusercontent.com/0p9b/claude-code-lean/main/install.sh | bash

Menu → confirm → install · Backs up your existing settings · Recommend: Balanced

See profiles Config breakdown

Four profiles (+ Both)

Ultra → Regular → Balanced → Custom. Option 4 installs Ultra + Regular launchers together.

1

Ultra Lean

~4.5–5k · most stripped

Minimal custom system prompt. Six core tools only.

Run: claude-lean

2

Regular Lean

~6.5k tokens

Same six tools + Claude Code’s default lean system prompt.

Run: claude

Recommended 3

Balanced

~7–9k · practical

Default prompt + Glob/Grep/TodoWrite + thinking. Still blocks MCP, Agent, skills.

Run: claude

4

Both

Ultra + Regular

Convenience: install both launchers with lean 6-tool settings.

Run either command

5

Custom

Wizard-driven

Pick launcher, effort, and tool packs interactively.

See packs →

Skip the menu (non-interactive)

curl -fsSL https://raw.githubusercontent.com/0p9b/claude-code-lean/main/install.sh | CLAUDE_LEAN_MODE=balanced bash

Customize later

The installer prints exact paths. Edit these anytime — or re-run the installer (it backs up first).

~/.claude/settings.json Tools deny list, effort, thinking, memory, disables
~/.claude/output-styles/lean.md Short output style (“Be brief.”)
~/.local/bin/claude-lean Ultra launcher (replaces product system prompt)
~/.claude/system-prompt-lean.txt Ultra system prompt text
~/.claude/claude-lean.conf Custom tool list for claude-lean (Custom mode)

Full reference: config breakdown

What you get

Opinionated defaults for a smaller, faster Claude Code session.

Lean base (6 tools)

Bash · Read · Write · Edit · WebSearch · WebFetch

Balanced adds

Glob · Grep · TodoWrite · thinking on

Still off

MCP, Agent, skills, Task*, LSP, memory, hooks, CLAUDE.md

Safe install

Atomic writes · backs up settings.json · validates JSON

After install

1

Restart any open Claude Code sessions

2

Run claude or claude-lean

3

Type /context to verify token usage

Requires Claude Code CLI and curl. Custom mode also needs python3. If claude-lean isn’t found: export PATH="$HOME/.local/bin:$PATH"