tweakcc

Overview of tweakcc

What it is

tweakcc is a CLI tool that modifies Claude Code's system prompts, UI, and behavior. It patches Claude Code's minified cli.js file on native/binary and npm-installed versions across Windows, macOS, and Linux. Created by the team behind Piebald, tweakcc is open source under the MIT license and supports both direct use via npx or pnpm dlx and programmatic use via its npm API (added in version 4.0.0). It works with multiple Node version managers (nvm, fnm, n, volta, nvs, nodenv) and package managers (npm, yarn, pnpm, bun, Homebrew/Linuxbrew, Nix). The current verified Claude Code version is 2.1.162, but system prompt patches work for any version >=2.0.14.

Key features

• Customize Claude Code's system prompts, create custom toolsets usable with a /toolset command, and highlight input patterns with custom colors and styling.
• Create custom themes using a graphical HSL/RGB color picker; customize thinking verbs, spinner animations, user message styling, and input box appearance.
• Add AGENTS.md support, session memory, a /remember skill, Opus Plan 1M mode, auto-accept plan mode, and a /title or /rename command for naming sessions.
• Speed up startup by ~50% with non‑blocking MCP connections; change context limit via CLAUDE_CODE_CONTEXT_LIMIT; add the opusplan[1m] model alias.
• Create custom patches with sandboxed scripts (tweakcc adhoc-patch) without forking the project; apply customizations from a remote URL.
• Includes built‑in patches for table format switching, token count rounding, statusline throttling, scroll escape sequence filtering, tmux graphics passthrough, and more.

Use cases

• Developers wanting to tailor Claude Code's system prompts and UI to their preferred appearance and behavior.
• Teams who want to distribute shared toolsets or remote configuration files to standardize Claude Code setups.
• Users who need to patch Claude Code's native binary (including on Apple Silicon) and reapply customizations after updates.
• Anyone experimenting with session memory, subagent model selection, or MCP startup optimization.

Getting started

To run without installation:bash$ npx tweakcc# Or use pnpm:$ pnpm dlx tweakccFor programmatic use, add it to your project: npm i tweakcc. After applying customizations, you can reapply them with tweakcc --apply (or –-yes to skip confirmation).

License and pricing

This project is open source under the MIT license. The repository is hosted at https://github.com/Piebald-AI/tweakcc.

Based on the project's public README and repository metadata.