{"name":"claude-sonnet-5","slug":"claude-sonnet-5","family":"model","title":"Models","noun":"model","description":"Sonnet 5's default context window is now a full million tokens, up from 967,000.","description_source":"entry","described_by":{"version":"2.1.247","anchor":"sonnet-5-default-context-window-raised-to-1-000-000-tokens"},"presence":{"first_seen":null,"removed_in":null,"in_current_build":false,"newest_mined":"2.1.308","builds":0,"mined_builds":149,"first_cited":{"version":"2.1.197","released_at":"2026-06-30 13:31:18","spans":5}},"aliases":[],"entries":[{"version":"2.1.290","anchor":"medium-and-high-effort-now-map-to-a-different-measured-profi","heading":"\/code-review medium now runs the high-effort recipe on most models","line":"On every model without its own `\/code-review` row, Opus 5.5 included, `medium` now runs the eight-angle high recipe instead of a single pass. `high`, `xhigh` and Opus 5 are unchanged.","released_at":"2026-10-05 18:12:44","reason":"found in this entry's text"},{"version":"2.1.287","anchor":"claude-5-sonnet-model-entry-drops-native-1m-3p-flags","heading":"Sonnet model entries no longer mark Bedrock, Vertex and Foundry as natively 1M","line":"Two Sonnet model entries no longer flag Bedrock, Vertex and Foundry as supporting the 1M-token context window natively","released_at":"2026-10-01 16:59:25","reason":"found in this entry's text"},{"version":"2.1.285","anchor":"claude-sonnet-5-gets-high-effort-thinking-entry-in-model-lis","heading":"Effort picker shows high as Recommended, and claude-sonnet-5 is listed with high effort","line":"The high effort option is now labelled Recommended instead of Default, and the model list includes `claude-sonnet-5` set to high effort","released_at":"2026-09-29 17:32:09","reason":"found in this entry's text, named in this entry"},{"version":"2.1.285","anchor":"model-catalog-claude-sonnet-5-default-thinking-opus-55-de","heading":"Model picker updates: Sonnet 5 thinking default, new Opus 5.5 wording, Recommended badge","line":"claude-sonnet-5 now defaults to high effort with automatic thinking, Opus 5.5 has new wording, and the High effort badge says Recommended","released_at":"2026-09-29 17:32:09","reason":"found in this entry's text"},{"version":"2.1.285","anchor":"effort-picker-badge-changed-from-default-to-recommended-one","heading":"Effort choices are labelled Recommended, and one model defaults to medium effort","line":"The effort picker labels medium and high as Recommended instead of Default, and one model's default effort drops from high to medium","released_at":"2026-09-29 17:32:09","reason":"found in this entry's text"},{"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"},{"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"},{"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"},{"version":"2.1.282","anchor":"bundled-model-catalog-opus-5-moved-to-the-overflow-sectio","heading":"Opus 5 moved to the overflow section of the built-in model list","line":"In the built-in model list, Opus 5 moves to the overflow section and loses its quick-select flag and description","released_at":"2026-09-24 15:56:22","reason":"found in this entry's text"}],"entries_total":19,"docs":[{"source":"api","path":"about-claude\/model-deprecations","title":"model-deprecations","documented":false},{"source":"api","path":"about-claude\/models\/migration-guide","title":"Or, for the model with the same capabilities and no access approval requirement:","documented":false},{"source":"api","path":"about-claude\/models\/model-ids-and-versions","title":"model-ids-and-versions","documented":false},{"source":"api","path":"about-claude\/models\/optimizing-for-cost-and-intelligence","title":"optimizing-for-cost-and-intelligence","documented":false},{"source":"api","path":"agents-and-tools\/agent-skills\/claude-api-skill","title":"claude-api-skill","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}],"docs_total":12,"gates":[],"related":[{"name":"claude-sonnet-4-0","slug":"claude-sonnet-4-0","description":"Switching to any Sonnet model name ending in [1m] now checks for 1M-context access, except four older Sonnet models"},{"name":"claude-sonnet-4-5","slug":"claude-sonnet-4-5","description":"Writing a file you have not read is now decided locally by model and permissions, not a server flag."},{"name":"claude-sonnet-4-5-20250929","slug":"claude-sonnet-4-5-20250929","description":"The dated first-party API id of Sonnet 4.5 (`claude-sonnet-4-5` in Claude Code's model table), also used for the `anthropic_aws`, `anthropic_google_cloud` and `gateway` providers. On the first-party provider, when certain account checks pass, a startup migration rewrites a user-settings `model` of `claude-sonnet-4-5-20250929` or `sonnet-4-5-20250929` (with or without `[1m]`) to `sonnet` or `sonnet[1m]`."},{"name":"claude-sonnet-4-6","slug":"claude-sonnet-4-6","description":"Context limits for claude-sonnet-5 are 500,000 on two surfaces and a million elsewhere."},{"name":"claude-sonnet-5-5","slug":"claude-sonnet-5-5","description":"Sonnet 5.5 (`claude-sonnet-5-5`) is now in the model list and is what `sonnet` picks when using Anthropic directly"}],"url":"https:\/\/changelogs.core-directive.com\/reference\/model\/claude-sonnet-5","family_url":"https:\/\/changelogs.core-directive.com\/reference\/model.json"}