Pro plan users may be assigned to experiments that change default model selection:
- Haiku default: Some Pro users may see Haiku 4.5 as default instead of Sonnet 4.5 (cost optimization)
- Sonnet 1M default: Users with 1M context access may default to Sonnet 4.5 [1M] instead of [200K]
These are A/B tests controlled by feature flags and not visible to all users.
Evidence
New functions r_1() at line 144169 and QH0() at line 144180 in pretty-v2.0.24.js
Strings lifted out of the shipped bundle, so the claim above can be checked against them.