Add OpenRouter integration and custom CLI name feature

[t1m3c]

Overview

This PR adds two major features to enhance the Gemini CLI experience:

🔗 OpenRouter Integration

Adds support for using OpenRouter's unified API as an alternative to Google's Gemini API, providing access to multiple AI models through a single interface.

🎨 Custom CLI Name Feature

Allows users to personalize their CLI experience by using custom names instead of "Gemini" in the interface.

Features Added

OpenRouter Integration

• Alternative API Provider: Use OpenRouter instead of Google's Gemini API
• Unified Model Access: Access to multiple AI models (Claude, GPT, Llama, etc.) through OpenRouter
• Seamless Integration: Automatic detection and configuration
• Full Feature Support: Streaming, function calling, and all existing CLI features work with OpenRouter

Usage:

export OPENROUTER_API_KEY="your-key-here"
export OPENROUTER_BASE_URL="https://openrouter.ai/api/v1"  # optional
gemini  # automatically detects and uses OpenRouter

Custom CLI Name Feature

• Personalized Interface: Use any custom name instead of "Gemini"
• Dynamic ASCII Art: Header displays your custom name in ASCII art
• Custom Prompt: Prompt symbol uses your custom name (e.g., "alice>" instead of ">")
• Flexible Names: Works with any name length and format

Usage:

gemini --cli-name "alice"
gemini --cli-name "my-assistant"

Technical Implementation

OpenRouter Integration

• New OpenRouterContentGenerator class implementing the same interface as Gemini's API
• Automatic provider detection based on environment variables
• Request/response translation between Gemini and OpenRouter formats
• Support for streaming responses and function calling
• Comprehensive error handling and logging

Custom CLI Name Feature

• Added customCliName setting to configuration system
• New --cli-name CLI argument
• Utility functions for name management and ASCII art generation
• Updated all UI components to use custom names dynamically
• Maintains backward compatibility (defaults to "Gemini")

Files Changed

Core Changes

• packages/core/src/core/openRouterContentGenerator.ts - New OpenRouter API integration
• packages/core/src/core/contentGenerator.ts - Provider detection logic
• packages/cli/src/config/settings.ts - Added customCliName setting
• packages/cli/src/config/config.ts - Added CLI argument handling

UI Updates

• packages/cli/src/ui/components/Header.tsx - Custom ASCII art support
• packages/cli/src/ui/components/messages/UserMessage.tsx - Custom prompt symbol
• packages/cli/src/ui/components/InputPrompt.tsx - Custom prompt in input
• packages/cli/src/ui/components/HistoryItemDisplay.tsx - Pass settings to components
• packages/cli/src/ui/App.tsx - Coordinate settings across components
• packages/cli/src/ui/utils/cliName.ts - New utility functions

Documentation

• docs/openrouter.md - Comprehensive OpenRouter setup guide
• docs/custom-cli-name.md - Custom CLI name feature documentation
• README.md - Updated with both features
• OPENROUTER_INTEGRATION_SUMMARY.md - Technical implementation details

Testing

• ✅ All existing tests pass
• ✅ TypeScript compilation successful
• ✅ Linting passes without errors
• ✅ Manual testing of both features completed
• ✅ OpenRouter integration tested with multiple models
• ✅ Custom CLI name tested with various name formats

Backward Compatibility

Both features are fully backward compatible:

• OpenRouter: Only activates when OpenRouter environment variables are set
• Custom CLI Name: Defaults to "Gemini" when no custom name is provided
• All existing functionality remains unchanged

Benefits

For Users

• Choice of AI Provider: Use OpenRouter for access to multiple models
• Cost Optimization: Potentially lower costs through OpenRouter's pricing
• Personalization: Customize the CLI experience with personal names
• Enhanced UX: More engaging and personalized interface

For Developers

• Modular Architecture: Clean separation between API providers
• Extensible Design: Easy to add more providers in the future
• Consistent Interface: Same CLI experience regardless of provider
• Comprehensive Documentation: Well-documented features and setup

Future Enhancements

• Support for additional API providers
• Model-specific optimizations for OpenRouter
• Advanced customization options for CLI appearance
• Integration with more OpenRouter features

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This PR significantly enhances the Gemini CLI by providing both functional improvements (OpenRouter integration) and user experience enhancements (custom CLI names), making the tool more flexible and personalized for users.

@t1m3c can click here to continue refining the PR