Gemini 2.5 Pro is a top-tier multimodal large language model from Google DeepMind designed for complex reasoning, robust code generation, and long-context understanding. It natively supports multimodal inputs, large context windows (commonly reported as 1M tokens, with some builds/reporting indicating higher windows), built-in function calling, and grounding integrations. The model is available through multiple integration surfaces (Gemini CLI, Gemini API key, and Vertex AI) and supports developer workflows with tools like file ops, shell command execution, web fetching, Google Search grounding, and MCP extensibility. It's used for coding assistance, long-form document comprehension, audio transcription and diarization, and production deployments via Vertex AI with usage-based billing.