tweakcc
A CLI tool that upgrades your Claude Code experience with custom system prompts, themes, toolsets, UI tweaks, and performance optimizations.
What is tweakcc?
tweakcc is a CLI tool that patches and customizes Anthropic's Claude Code AI coding assistant. It allows developers to modify system prompts, create custom toolsets, apply themes, and unlock advanced features like AGENTS.md support and performance optimizations. The tool solves the problem of limited customization in the standard Claude Code installation by providing safe, reversible modifications.
Developers using Claude Code who want deeper customization, performance improvements, and access to advanced features not available in the vanilla installation. Particularly valuable for power users who work with multiple toolsets, need specific system prompts, or want to optimize their AI coding workflow.
tweakcc provides unparalleled customization of Claude Code through a safe patching system that works across all installation methods. Unlike manual modifications, it offers an intuitive interface, version-aware prompt management, and the ability to create and share custom configurations while maintaining the ability to revert changes easily.
Overview
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.
Use Cases
Best For
- Customizing Claude Code's system prompts for specific development workflows
- Creating focused toolsets to reduce prompt token usage and improve performance
- Applying custom themes and UI tweaks to personalize the coding assistant interface
- Speeding up Claude Code startup time when using multiple MCP servers
- Unlocking advanced features like AGENTS.md support and session memory
- Managing different Claude Code configurations across projects or teams
Not Ideal For
- Environments with strict security policies against binary modification
- Teams that require immediate, hassle-free updates to the latest Claude Code versions
- Developers who prefer a fully vendor-supported, out-of-the-box AI assistant experience
- Projects where stability and minimal setup are higher priorities than deep customization
Pros & Cons
Pros
Enables editing all Claude Code system prompts via markdown files, allowing precise control over AI behavior for specific workflows, as detailed in the system prompts section.
Speeds up Claude Code startup by ~50% with non-blocking MCP connections and configurable batch sizes, directly addressing slow startup with multiple servers.
Unlocks hidden features like AGENTS.md support and session memory, patching high-demand gaps not available in vanilla Claude Code, as shown in the features list.
Works on Windows, macOS, and Linux with both native and npm installs, using node-lief for binary patching to ensure broad compatibility.
Cons
Patches are verified for Claude Code 2.1.62, but may break with newer versions, requiring manual updates and causing instability, as admitted in the README.
Troubleshooting section reveals backup corruption loops that can force reinstallation, adding maintenance overhead and potential data loss.
Features like bypassing permissions in sudo disable security checks, introducing risks if misused, with warnings in the README about dangerous implications.
Frequently Asked Questions
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