Claude Code Makes Opus 5 the Default Model for Enterprise Seats
Claude CodeClaude Code 2.1.251 changed the default model for seat-based Enterprise subscriptions to Opus 5, bringing it in line with Max, Team Premium, and other premium plans that already defaulted to Opus 5. Enterprise seat-based subscribers previously defaulted to Sonnet 5 even though Opus 5 had been available as an option since it shipped in July. The change means Enterprise developers get Anthropic's most capable model out of the box without needing to switch it manually.
Key Takeaways
- Seat-based Enterprise subscriptions now default to Opus 5, matching Max and Team Premium, instead of defaulting to Sonnet 5 as before.
- Enterprise pay-as-you-go already defaulted to Opus 5, so this change closes the gap between Enterprise's seat-based and usage-based billing models.
- The change is a default only, not a forced switch: developers who explicitly pinned Sonnet 5 keep their existing choice.
- Opus 5 has been available in Claude Code since July 2026 (v2.1.219+), with pricing unchanged from Opus 4.8.
- It lands in the same release as new
/usageand/costvisibility features, including a per-session prompt-cache line, making the cost of a more expensive default model easier to track. - The move reflects Anthropic positioning Opus 5 as the expected baseline for its highest-tier paying customers rather than an opt-in premium choice.
Claude Opus 5 shipped in July 2026 with a 1M-token context window and pricing unchanged from Opus 4.8, and it was quickly made the default model on Max and Team Premium plans. Seat-based Enterprise subscriptions, however, kept defaulting to Sonnet 5, leaving Enterprise developers to switch models manually with /model if they wanted Opus 5's extra capability.
What Changed
With Claude Code 2.1.251, released August 28, 2026, Anthropic changed the default model for seat-based Enterprise subscriptions to Opus 5, matching the default already used on other premium plans. Enterprise pay-as-you-go organizations, which bill by usage rather than by seat, already defaulted to Opus 5, so this closes the last gap between Enterprise's two billing models.
Why It Matters
For Enterprise teams, the practical effect is that a new session started under a seat-based Enterprise plan now opens with Opus 5 rather than Sonnet 5, without any configuration change on the administrator's or developer's part. Anyone who had pinned Sonnet 5 explicitly, through /model or a modelPicker setting, keeps that choice; the change only affects what a fresh session picks by default. Combined with the same release's Opus 5 spend-visibility additions to /usage and /cost, it signals Anthropic treating Opus 5 as the baseline expectation for its highest-paying customer tier rather than an opt-in upgrade.