{"version":"2.0.0","anchor":"claude-sonnet-4-5-model","canonical_anchor":"claude-sonnet-4-5-model","heading":"Claude Sonnet 4.5 Model","tier":null,"area":null,"scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.0.0\/e\/claude-sonnet-4-5-model","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.0.0","markdown":"### Claude Sonnet 4.5 Model\n\n**What:** New default model `claude-sonnet-4-5-20250929` with improved performance for daily coding tasks\n\n**How to use:**\n\n`# Sonnet 4.5 is now the default - no changes needed claude # Or explicitly specify it claude --model sonnet45` **Details:**\n\n- Available across all platforms (first-party API, Bedrock, Vertex AI)\n- Automatic migration from previous default models\n- Described as \"Smartest model for daily use\"\n- Supports 1M token context window variant: `claude-sonnet-4-5[1m]`\n- **Evidence**: `U10` at line 367516, `GM1()` at line 368315, model detection logic at line 340617 in v2.0.0"}