Anthropic: claude-opus-4:free

Claude Opus 4 (20250514) is the premier flagship model of Anthropic's fourth generation, widely regarded as the most powerful coding and research model of early 2025. It represents the pinnacle of intelligence and reasoning depth within the Claude 4 family. Featuring a revolutionary "Extended Thinking" mode, it can sustain autonomous task execution for several hours. Scoring a record 72.5% on SWE-bench, it excels at complex architecture refactoring across thousands of files while maintaining flawless logical consistency. Opus 4 is engineered for scenarios requiring maximum precision, long-range planning, and sophisticated tool-agent workflows.