{"version":"2.1.75","anchor":"opus-1m-context-window-default","canonical_anchor":"opus-1m-context-window-default","heading":"Opus 1M Context Window Default","tier":null,"area":null,"scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.75\/e\/opus-1m-context-window-default","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.75","markdown":"### Opus 1M Context Window Default\n\n**What**\n\nFirst-party Opus users now default to a 1M token context window (5x larger), with automatic migration from the standard Opus setting.\n\n**Details**\n\n- Controlled by the `tengu_cobalt_compass` feature flag (gradual rollout)\n- Users who had \"opus\" selected are automatically migrated to \"opus[1m]\"\n- A merge notice is shown up to 6 times: \"Opus now defaults to 1M context \u00b7 5x more room, same pricing\"\n- When Opus 1M is active, Opus no longer triggers \"Billed as extra usage\" \u2014 same pricing as before\n- The model picker now offers an explicit \"Opus (1M context)\" entry labeled `[NEW]`\n\n**Evidence**\n\nOpus 1M migration and display (search for `\"tengu_cobalt_compass\"`, `\"Opus now defaults to 1M context\"`, `\"tengu_opus_to_opus1m_migration\"`)\n\n- Flag `tengu_cobalt_compass`: On for this account, and not off by default (read for one account on one subscription tier against v2.1.75; this account: on, anonymous baseline: on, compiled default: no gate table built for this version) These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release."}