Standardize LLM configuration and improve environment setup

[kahnu044]

Summary

This PR improves the LLM configuration and developer experience by introducing a more flexible and provider-agnostic environment setup.

Changes

1. LLM Configuration

• Added LLM_MODEL environment variable

  • Allows overriding the default model from config.yaml without modifying source code

2. API Key Standardization

• Renamed CHATGPT_API_KEY → OPENAI_API_KEY

• Aligned API key naming with provider-specific conventions:

  • OPENAI_API_KEY
  • ANTHROPIC_API_KEY
  • OPENROUTER_API_KEY

• Ensures compatibility with LiteLLM multi-provider routing

3. Project Setup Improvements

• Updated .gitignore:

  • Ignore virtual environments (.venv)
  • Ignore generated results/output files

4. Documentation Updates

• Added virtual environment setup instructions
• Documented usage of LLM_MODEL for overriding default models
• Clarified provider-based API key naming conventions with LiteLLM

Impact

• Improves flexibility for switching models and providers
• Removes the need to modify source code for configuration changes
• Aligns project with industry-standard LLM environment practices
• Enhances onboarding experience for new developers

Notes

• Existing setups using CHATGPT_API_KEY will need to migrate to OPENAI_API_KEY
• No breaking changes to core functionality

[claude]

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[kahnu044]

@claude review

[saccharin98]

⏺ Hi @kahnu044, thanks for the contribution!

We're closing this PR as the codebase has diverged since it was opened. The LiteLLM integration (#168) is
already in place — users familiar with LiteLLM can configure providers and models directly via config.yaml or
the model parameter, following standard LiteLLM conventions.

Thanks again for the effort!