Why Your API Usage Records Show a Different Model Than You Selected

Key Info

An API provider addresses user reports that requests made with one model (e.g., Claude Opus 5.5 in Claude Code) sometimes appear in usage records under another model (e.g., Sonnet 5), and explains that this does not necessarily mean the provider silently switched models.

Highlights

• Subagent tasks within Claude Code can invoke different models as part of the same workflow.
• Fallback mechanisms may route requests to a backup model when the primary model is unavailable or a request fails, depending on client configuration.
• Auto-selection, model aliases and subtask model settings can also cause the actual model to differ from the one expected.
• Platforms may apply documented version mappings or upgrade routing to legacy model IDs.
• To verify, check the model ID in the API request, compare model info, timestamps and billing in usage records, and submit Request ID plus screenshots to support if the discrepancy persists.