Gemini is often the cheaper available quota for low-stakes semantic graph extraction, while OpenAI is a useful fallback. Extend the direct extraction backend registry, CLI validation, docs, and tests so headless extraction can use GEMINI_API_KEY, GOOGLE_API_KEY, or OPENAI_API_KEY without changing the existing Claude and Kimi paths.
Constraint: Gemini supports OpenAI-compatible chat completions at the Google generative-language endpoint
Rejected: Native google-genai integration | higher dependency and response-shape churn for the same chat-completions path
Confidence: medium
Scope-risk: moderate
Directive: Keep backend detection explicit and test every accepted API-key environment variable before adding new providers
Tested: uv run --directory vendor/graphify pytest tests/test_llm_backends.py tests/test_chunking.py -q
Not-tested: Live Gemini/OpenAI API calls; no GEMINI_API_KEY or OPENAI_API_KEY present in this environment
Daniel Graham
a9cb692961