Fallback Model
ai-gateway-fallback-model-v2
Fallback Model adds two kinds of backup to an app's model selection, per capability:
fallback—the model to try after a provider error that can be retried, or after a timeout.quotaFallback—the model to use when a usage limit is hit, instead of rejecting the request. Budgets and Costs is what applies this.
fallbackTimeoutSeconds controls how long the gateway waits before giving up on
the main model and trying the fallback. It defaults to 60 seconds and accepts 1
to 300. A fallback that names the same model as the main one is skipped.
This policy only enriches a model selection that already exists—it never creates one. An app whose chain has Fallback Model but no Model Filtering does nothing at all: the policy logs a warning and passes the request through unchanged. Place Fallback Model immediately after Model Filtering.
That ordering is also why a fallback can never widen what an app may reach—the filter has already accepted or rejected the request by the time this policy runs.
For the portal workflow and worked examples see Fallback Models; for every option see the generated reference.