{"version":"2.1.280","anchor":"opus-55-model-added","canonical_anchor":"opus-55-model-added","heading":"Opus 5.5 model added","tier":"use","area":"Models","url":"https:\/\/changelogs.core-directive.com\/v\/2.1.280\/e\/opus-55-model-added","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.280","markdown":"### Opus 5.5 model added\n\nNew Opus 5.5 model added with a 1M-token context window and its own pricing tier\n\n**What**\n\nA new model, `claude-opus-5-5` (display name \"Opus 5.5\"), has been added to Claude Code's model registry, with provider IDs across Bedrock, Vertex, and Foundry, a 1-million-token context window, and its own pricing tier. It's now recognized as a valid model ID throughout the client: in the model-name normalization table, the list of models allowed the 1M-token\/auto-compact context window, and the model-family checks used for capabilities like fast mode and thinking.\n\nThe system prompt now lists \"Opus 5.5: claude-opus-5-5\" as the most capable model, in place of the previous \"Opus 5\" entry, and no longer ties fast mode's availability to \"Opus 5\/4.8.\"\n\n**Why**\n\nThis makes Opus 5.5 usable across Claude Code's model selection, context-window handling, and pricing, and it becomes the model the system prompt now points to as the most capable option.\n\n- Area: Models\n- Names: `claude-opus-5-5`\n- Tier: Use it now\n- Useful: 5\/5\n- Signal: 3\/5"}