HarnessModelRoutingContext
Parameters and properties
Section titled “Parameters and properties”systemRequiredstringSession instructions already resolved once for the run.messagesRequiredreadonly ModelMessage[]Current post-compaction messages; custom state builders must explicitly exclude any opaque reasoning they do not need.toolsRequiredreadonly ModelToolSpec[]Available model-facing tool declarations for this step.stepRequirednumberOne-based harness step about to request a conversational model.modelRequiredAgentModelActive effective model before the new selection, also used by preceding compaction.signalRequiredAbortSignalRun cancellation signal; state callbacks and providers should honor it.