Gemini 2.5 Flash

At its core, Flash is Google's speed-and-scale tier: a Transformer decoder with dynamic thinking-level control that lets you dial reasoning depth against latency budget. The 1M-token input window handles multi-file codebases and long documents without chunking gymnastics — which means you avoid the retrieval errors that haunt smaller-context models. Tool-use benchmarks put it at 83.6% on MCP Atlas and 76.2% on Terminal-Bench 2.1, the vendor states, making it credible for agents that run tasks on their own across real environments. The ceiling appears at output: 65,536 tokens out, which stops cold any workflow that needs to generate an entire large codebase in a single pass. Teams hitting that wall split generation into multi-turn loops, which adds state management complexity they did not plan for.