new BaseSpan(type: "agent" | "llm" | "retriever" | "tool" | "workflow" | "trace" | "session", data: BaseSpanOptions): BaseSpan;

createdAt: Date;

optional datasetInput: string;

optional datasetMetadata: Record<string, string> = {};

optional datasetOutput: string;

optional externalId: string;

input: StepAllowedInputType;

metrics: Metrics;

name: string = "";

optional output: StepAllowedOutputType;

optional redactedInput: StepAllowedInputType;

optional redactedOutput: StepAllowedOutputType;

optional statusCode: number;

optional stepNumber: number;

optional tags: string[];

type: "agent" | "llm" | "retriever" | "tool" | "workflow" | "trace" | "session";

userMetadata: Record<string, string> = {};

toJSON(): Record<string, any>;

validateInputOutputSerializable<T>(val: T): T;