Issue: Refactor Claude Code Provider to Use Direct API Calls Like Gemini CLI

[hellosunghyun]

Current Problem with Claude Code Implementation

The current Claude Code implementation has several reliability and maintainability issues:

1. Process Management Complexity

The current approach spawns external CLI processes with complex stdin/stdout management, which introduces multiple failure points including process timeouts, buffer overflows, and platform-specific issues.

2. Error-Prone Process Communication

Writing JSON to stdin and parsing stdout streams is fragile and can fail due to race conditions, partial data, or process termination issues.

Proposed Solution: Follow Gemini CLI Pattern

The Gemini CLI implementation demonstrates a much cleaner approach:

1. Direct HTTP API Calls

Instead of spawning processes, Gemini CLI makes direct authenticated HTTP requests to Google's API endpoints, which is more reliable and easier to debug.

2. Robust OAuth Authentication

The OAuth credential management with automatic token refresh is more robust than relying on CLI authentication state.

3. Cleaner Response Processing

Direct API responses are easier to parse and handle than CLI stdout streams.

Benefits of the Proposed Change

1. Improved Reliability: Eliminates process management overhead and potential CLI crashes
2. Better Error Handling: Direct API errors are easier to catch and handle gracefully
3. Reduced Dependencies: No need to ensure Claude CLI is installed and properly configured
4. Consistent Architecture: Aligns with the cleaner Gemini CLI implementation pattern
5. Easier Testing: Direct API calls are much easier to mock and test than subprocess interactions

Implementation Considerations

While this change would require investigating if Anthropic provides similar OAuth-based API access like Google does for Gemini, the architectural benefits make it worth exploring. The current CLI-based approach introduces unnecessary complexity and potential failure points that could be eliminated with a direct API implementation.

The Gemini CLI implementation shows this pattern works well and provides a good template for how Claude Code could be refactored for better reliability and maintainability.

If necessary, I will contribute.