{"version":"2.1.265","anchor":"opus-1m-context-restriction-extended-to-opusplan1m","canonical_anchor":"opus-1m-context-restriction-extended-to-opusplan1m","heading":"Opus 1M-context restriction extended to opusplan[1m]","tier":"notice","area":"Models","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.265\/e\/opus-1m-context-restriction-extended-to-opusplan1m","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.265","markdown":"### Opus 1M-context restriction extended to opusplan[1m]\n\nThe 1M-context restriction that blocks certain Sonnet model switches now also blocks opusplan[1m]\n\n**What**\n\nClaude Code has a check that prevents switching to a 1-million-token context window for certain models, previously applied to `sonnet[1m]`, `sonnet-4-6[1m]`, and `sonnet-5[1m]`. That same restriction now also applies to the model string `opusplan[1m]`.\n\n**Why**\n\nThis closes a gap where `opusplan[1m]` could be selected without the same 1M-context restriction that already applied to the equivalent Sonnet variants.\n\n- Area: Models\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 1\/5"}