Silent Model Downgrade
- Entity ID:
ent-20260419-f3d01d013c11 - Type:
concept - Scope:
shared - Status:
active - Aliases: FallbackTriggeredError, Opus-to-Sonnet downgrade, consecutive529 downgrade
Description
Confirmed source-level behavior: after MAX_529_RETRIES consecutive 529 errors the client throws FallbackTriggeredError and silently switches the user from options.model (e.g., Opus) to options.fallbackModel (e.g., Sonnet). No user notification. Combined with the 9.3% server-overloaded failure rate in Kolkov's data, affects paying Opus users systematically.
Key claims
- Opus users silently downgraded to Sonnet after 3 consecutive 529s
Relations
- Silent Model Downgrade --[contained_in]--> Claude Code