{"name":"tengu_opus_to_opus1m_migration","slug":"tengu-opus-to-opus1m-migration","family":"flag","title":"Feature flags","noun":"feature flag","description":"An analytics event, not a feature flag. Claude Code logs it, with no fields, when a startup migration rewrites a user settings `model` of `opus` to `opus[1m]` and the write succeeds. The migration does nothing when the user setting is not `opus` or when an eligibility check fails (for example on a non-first-party API provider).","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":"2.1.309","builds":0,"mined_builds":150,"first_cited":{"version":"2.1.75","released_at":"2026-03-13 15:51:07","spans":1}},"aliases":[],"entries":[{"version":"2.1.75","anchor":"opus-1m-context-window-default","heading":"Opus 1M Context Window Default","line":null,"released_at":"2026-03-13 15:51:07","reason":"gate cited by this entry, found in this entry's text"}],"entries_total":1,"docs":[],"docs_total":0,"gates":[],"related":[{"name":"tengu_opus_default_pro_plan","slug":"tengu-opus-default-pro-plan","description":null}],"url":"https:\/\/changelogs.core-directive.com\/reference\/flag\/tengu-opus-to-opus1m-migration","family_url":"https:\/\/changelogs.core-directive.com\/reference\/flag.json"}