{"name":"claude-sonnet-4-5-20250929","slug":"claude-sonnet-4-5-20250929","family":"model","title":"Models","noun":"model","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]`.","description_source":"code","described_by":{"bundle":"2.1.286","author":"claude-opus-5-5"},"presence":{"first_seen":null,"removed_in":null,"in_current_build":false,"newest_mined":"2.1.308","builds":0,"mined_builds":149,"first_cited":null},"aliases":[],"entries":[{"version":"2.1.67","anchor":"automatic-sonnet-4-5-sonnet-4-6-migration","heading":"Automatic Sonnet 4.5 \u2192 Sonnet 4.6 Migration","line":null,"released_at":"2026-03-04 05:31:10","reason":"found in this entry's text"},{"version":"2.0.0","anchor":"claude-sonnet-4-5-model","heading":"Claude Sonnet 4.5 Model","line":null,"released_at":"2025-09-29 14:41:14","reason":"found in this entry's text"}],"entries_total":2,"docs":[{"source":"api","path":"about-claude\/model-deprecations","title":"model-deprecations","documented":false},{"source":"api","path":"about-claude\/models\/model-ids-and-versions","title":"model-ids-and-versions","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\/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":"api\/beta","title":"Beta","documented":false},{"source":"api","path":"api\/beta\/agents","title":"Agents","documented":false},{"source":"api","path":"api\/beta\/agents\/archive","title":"Archive Agent","documented":false},{"source":"api","path":"api\/beta\/agents\/create","title":"Create Agent","documented":false},{"source":"api","path":"api\/beta\/agents\/list","title":"List Agents","documented":false}],"docs_total":12,"gates":[],"related":[{"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."}],"url":"https:\/\/changelogs.core-directive.com\/reference\/model\/claude-sonnet-4-5-20250929","family_url":"https:\/\/changelogs.core-directive.com\/reference\/model.json"}