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tweakcc

tweakcc is a CLI tool that upgrades your Claude Code experience. Customize its system prompts, add custom themes, create toolsets, and personalize the UI. From the team behind Piebald.

[!IMPORTANT] NEW in 4.0.0: tweakcc now has an API; use npm i tweakcc to add to your project and see API!

NEW in 4.0.0: You can now create custom patches via sandboxed scripts! Works with native installations. No need to fork tweakcc just to make a quick patch! See tweakcc adhoc-patch.

NEW in 4.0.0: You can also apply customizations from a remote URL to a config file. See Remote Config.

Also see tweakcc --restore, tweakcc unpack, and tweakcc repack.

[!NOTE] NEW: tweakcc 4.0.0 also introduces several new patches:

• AGENTS.md support (demo video)
• :lock: unlock session memory (blog post) (thank you @odysseus0!)
• /remember skill
• input pattern highlighters
• Opus plan 1M
• MCP startup optimization
• token count rounding
• statusline throttling/pacing
• auto-accept plan mode (thank you @irdbl!)
• dangerously bypassing permissions in sudo (thank you @brrock!)
• native installer warning suppression (thank you @brrock!).

With tweakcc, you can

• Customize all of Claude Code's system prompts (NEW: also see all of Claude Code's system prompts)
• Create custom toolsets that can be used in Claude Code with the new /toolset command
• Highlight custom patterns while you type in the CC input box with custom colors and styling, like how ultrathink used to be rainbow-highlighted.
• Manually name sessions in Claude Code with /title my chat name or /rename (see our blog post for implementation details)
• Create custom themes with a graphical HSL/RGB color picker
• Add custom thinking verbs that will show while Claude's working
• Create custom thinking spinner animations with different speeds and phases
• Style the user messages in the chat history beyond the default plain gray text
• Remove the ASCII border from the input box
• Expand thinking blocks by default, so that you don't need to use the transcript (Ctrl+O) to see them
• Configure which Claude model each subagent (Plan, Explore, and general-purpose) uses
• Switch between table formats - Claude Code default, Unicode (┌─┬─┐), ASCII/markdown (|---|), Unicode without top/bottom borders.

tweakcc also

• Fixes a bug where the spinner animation is frozen if you have the CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC environment variable set (#46)
• Allows you to change the context limit (default: 200k tokens) used with models from custom Anthropic-compatible APIs with a new environment variable, CLAUDE_CODE_CONTEXT_LIMIT
• Adds the opusplan[1m] model alias, combining Opus for planning with Sonnet's 1M context for execution—reducing "context anxiety" (#108)
• Adds a message to Claude Code's startup banner indicating that you're running the patched version of CC (configurable)
• Speeds up Claude Code startup by ~50% with non-blocking MCP connections and configurable parallel connection batch size (#406)

tweakcc supports Claude Code installed on Windows, macOS, and Linux, both native/binary installations and those installed via npm, yarn, pnpm, bun, Homebrew/Linuxbrew, nvm, fnm, n, volta, nvs, nodenv, and Nix (including NixOS and nix-darwin), as well as custom locations.

tweakcc supports Claude Code's native installation, which is a large platform-specific native executable containing the same minified/compiled JavaScript code from npm, just packaged up in a Bun binary. We support patching the native binary on macOS, Windows, and Linux, including ad-hoc signing on Apple Silicon, via node-lief, our Node.js bindings for LIEF (Library to Instrument Executables).

While tweakcc has a large library of built-in patches, you can create custom patches by using tweakcc's API. If you don't want to create an npm package, you can use tweakcc adhoc-patch, which applies a custom Node.js script to your default Claude Code installation. Because adhoc-patch supports running scripts from an HTTP URL, you can even host a script on a GitHub Gist or pastebin for easy distribution.

Run without installation:

$ npx tweakcc

# Or use pnpm:
$ pnpm dlx tweakcc

Table of contents

• How it works
• Remote config
• CLI Commands (unpack, repack, adhoc-patch)
• API
• System prompts
• Toolsets
• Features
  • System prompts
  • Themes
  • Thinking verbs customization
  • Thinking indicator customizations
  • Context limit
  • LSP support
  • Hide "ctrl-g to edit prompt in <editor>"
  • Hide the startup banner
  • Hide the startup "Clawd" logo
  • Increase the max size in tokens for files read via Read
  • Remove the border from the message input box
  • Add all models to /model
  • tweakcc patches applied indicator
  • Show more items in select menus
  • Subagent models
  • Suppression of 1→ prefixes from Read output
  • Suppress /rate-limit-options from being injected
  • Swarm mode
  • Session memory
  • /remember skill
  • Toolsets
  • User message display customization
  • Token indicator display
  • Add support for dangerously bypassing permissions in sudo
  • Input pattern highlighters
  • Opus Plan 1M mode
  • MCP startup optimization
  • Table format
  • Token count rounding
  • Statusline update customization
  • AGENTS.md support (with video)
  • Auto-accept plan mode
  • Suppress native installer warning
  • Scroll escape sequence filter
  • Missing documentation for above features coming soon
• Configuration directory
• Building from source
• Troubleshooting
• FAQ
• Contributing
• Related projects
• License

How it works

tweakcc works by patching Claude Code's minified cli.js file, reading customizations from ~/.tweakcc/config.json. Fo