December 2025 highlights: Delivered reasoning support for the vertex_ai/gemini-3-flash-preview model in BerriAI/litellm. Introduced a supports_reasoning flag in the model configuration, enabling the model to process and respond with logical reasoning. This change is paired with updates to model pricing and context window behavior to reflect the new capability (#18175). No major bugs reported this month; focus was on feature delivery, stability, and preparing for broader use-cases. Business impact includes richer user interactions, expanded capabilities for complex queries, and potential reductions in support overhead as responses become more capable. Technologies/skills demonstrated include feature flag implementation, Vertex AI Gemini-3 integration, pricing/context window coordination, and commit-driven development (commit 1c401ecf716c3ecb1b98890c9704a8faddf6806f).