Piebald-AI/tweakcc

Customize Claude Code's system prompts, create custom toolsets, input pattern highlighters, themes/thinking verbs/spinners, customize input box & user message styling, support AGENTS.md, unlock private/unreleased features, and much more. Supports both native/npm installs on all platforms.

What it solves

tweakcc is a CLI tool designed to customize and enhance the experience of using Claude Code. It allows users to modify the system prompts, UI themes, and functional behavior of the Claude Code CLI without needing to fork the original project.

How it works

The tool works by patching the minified cli.js file of Claude Code. For npm-based installations, it modifies the file directly. For native binary installations, it uses node-lief to extract the JavaScript from the binary, applies the patches, and then repacks the binary. Customizations are stored in a local config.json file, allowing users to reapply their settings after updating Claude Code.

Who it’s for

Developers and power users of Claude Code who want to personalize their interface, optimize the tool's performance (such as startup speed), or modify the underlying system prompts and toolsets used by the AI agent.

Highlights

  • UI Customization: Create custom themes with a color picker, change thinking verbs and spinner animations, and style user messages.
  • System Prompt & Toolset Control: Customize all system prompts and create custom toolsets accessible via a new /toolset command.
  • Performance Optimizations: Speeds up startup by approximately 50% via non-blocking MCP connections.
  • Functional Enhancements: Adds session memory, /remember skill, and the ability to manually name sessions.
  • Advanced Patching: Supports ad-hoc patching via strings, regex, or sandboxed JavaScript scripts (which can be loaded from local files or remote URLs).
  • Model Configuration: Configure which Claude model each subagent (Plan, Explore, and general-purpose) uses.

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