What Claude models does Claude Code use?

By default, the latest production-tier Anthropic model — currently Claude Opus 4.7 for heavy coding tasks and Claude Sonnet 4.6 for fast routine work (May 2026). You can pin specific models with --model or set defaults in your .claude/config.json. Extended thinking mode kicks in automatically for complex tasks (architectural decisions, debugging). You can also route Claude Code via AWS Bedrock or GCP Vertex AI if your org requires cloud-vendor billing — the CLI picks up ANTHROPIC_BEDROCK_BASE_URL / ANTHROPIC_VERTEX_PROJECT_ID env vars.