{"version":"2.1.283","anchor":"sonnet-1m-context-availability-check-now-covers-any-sonnet","canonical_anchor":"sonnet-1m-context-availability-check-now-covers-any-sonnet","heading":"The Sonnet 1M-context check now covers full Sonnet model names","tier":"notice","area":"Models","url":"https:\/\/changelogs.core-directive.com\/v\/2.1.283\/e\/sonnet-1m-context-availability-check-now-covers-any-sonnet","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.283","markdown":"### The Sonnet 1M-context check now covers full Sonnet model names\n\nSwitching to any Sonnet model name ending in [1m] now checks for 1M-context access, except four older Sonnet models\n\n**Unclear.** Where the new \"denied_by_managed_settings\" and \"not_allowed\" labels are shown is not known.\n\n**What**\n\nWhen you switch models, Claude Code checks whether your account can use Sonnet with a 1 million token context window. The context window is how much text the model can hold at once. If your account cannot, you see \"Sonnet with 1M context is not available for your account\". This check used to catch only a few short names. It now applies to any model name containing both \"sonnet\" and \"[1m]\", and still to `opusplan[1m]`. These models are exempt:\n\n- `claude-sonnet-4-5`\n\n- `claude-sonnet-4-0`\n\n- `claude-3-7-sonnet`\n\n- `claude-3-5-sonnet`\n\nThere is also a new way to label a refused model switch as either \"denied_by_managed_settings\" or \"not_allowed\".\n\n**Why**\n\nFull Sonnet model names with [1m] used to get past this check. Accounts without 1M access now get the clear refusal up front instead.\n\n- Area: Models\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 1\/5"}