{"name":"claude-sonnet-5-5","slug":"claude-sonnet-5-5","family":"model","title":"Models","noun":"model","description":"Sonnet 5.5 (`claude-sonnet-5-5`) is now in the model list and is what `sonnet` picks when using Anthropic directly","description_source":"entry","described_by":{"version":"2.1.284","anchor":"sonnet-55-claude-sonnet-5-5-added-and-made-the-default-s"},"presence":{"first_seen":null,"removed_in":null,"in_current_build":false,"newest_mined":"2.1.284","builds":0,"mined_builds":127,"first_cited":{"version":"2.1.284","released_at":"2026-09-28 17:11:59","spans":6}},"aliases":[],"entries":[{"version":"2.1.284","anchor":"sonnet-55-claude-sonnet-5-5-added-and-made-the-default-s","heading":"Sonnet 5.5 added and made the default for the sonnet model name","line":"Sonnet 5.5 (`claude-sonnet-5-5`) is now in the model list and is what `sonnet` picks when using Anthropic directly","released_at":"2026-09-28 17:11:59","reason":"found in this entry's text, named in this entry"},{"version":"2.1.284","anchor":"sonnet-alias-now-resolves-to-sonnet-55-claude-sonnet-5-5","heading":"The sonnet model name now points to Sonnet 5.5 on the Anthropic API","line":"Choosing sonnet now selects Sonnet 5.5 instead of Sonnet 5 on the Anthropic API, while Bedrock, Vertex and other providers keep older models","released_at":"2026-09-28 17:11:59","reason":"found in this entry's text, named in this entry"},{"version":"2.1.284","anchor":"model-constants-move-to-opus-55-and-sonnet-55","heading":"Claude Code's built-in model list now points to Opus 5.5 and Sonnet 5.5","line":"Claude Code's built-in current models are now claude-opus-5-5 and claude-sonnet-5-5, with claude-opus-5 and claude-sonnet-5 as the previous ones","released_at":"2026-09-28 17:11:59","reason":"found in this entry's text"},{"version":"2.1.284","anchor":"refusal-fallback-now-has-its-own-route-for-claude-sonnet-5-5","heading":"Refused requests on Sonnet 5.5 now fall back to Sonnet 5","line":"When a Sonnet 5.5 request is refused as cyber or frontier_llm, Claude Code now falls back to claude-sonnet-5 instead of an Opus model","released_at":"2026-09-28 17:11:59","reason":"found in this entry's text, named in this entry"}],"entries_total":4,"docs":[{"source":"api","path":"about-claude\/model-deprecations","title":"model-deprecations","documented":false},{"source":"api","path":"agents-and-tools\/tool-use\/advisor-tool","title":"advisor-tool","documented":false},{"source":"api","path":"agents-and-tools\/tool-use\/browser-use-tool","title":"browser-use-tool","documented":false},{"source":"api","path":"agents-and-tools\/tool-use\/code-execution-tool","title":"code-execution-tool","documented":false},{"source":"api","path":"agents-and-tools\/tool-use\/computer-use-tool","title":"computer-use-tool","documented":false},{"source":"api","path":"agents-and-tools\/tool-use\/programmatic-tool-calling","title":"Process results programmatically","documented":false},{"source":"api","path":"agents-and-tools\/tool-use\/tool-search-tool","title":"tool-search-tool","documented":false},{"source":"api","path":"build-with-claude\/claude-in-amazon-bedrock","title":"claude-in-amazon-bedrock","documented":false},{"source":"api","path":"build-with-claude\/claude-in-microsoft-foundry","title":"claude-in-microsoft-foundry","documented":false},{"source":"api","path":"build-with-claude\/claude-on-vertex-ai","title":"claude-on-vertex-ai","documented":false}],"docs_total":12,"gates":[],"related":[{"name":"claude-sonnet-5","slug":"claude-sonnet-5","description":"Sonnet 5's default context window is now a full million tokens, up from 967,000."}],"url":"https:\/\/changelogs.core-directive.com\/reference\/model\/claude-sonnet-5-5","family_url":"https:\/\/changelogs.core-directive.com\/reference\/model.json"}