Class Tracer

constructor

• new Tracer(opts: TracerOptions): Tracer

  Creates a new tracer with the specified options.

  Parameters

  • opts: TracerOptions

    The options for configuring the tracer.

  Returns Tracer

ReadonlysessionId

message

• message(
      e: Omit<MessageEvent, "sessionId" | "type" | "ts" | "level" | "ctx"> & {
          ctx?: TraceContext;
      },
  ): Promise<unknown>

  Emits a message event, which can be from the system, user, assistant, or a tool.

  Parameters

  • e: Omit<MessageEvent, "sessionId" | "type" | "ts" | "level" | "ctx"> & {
        ctx?: TraceContext;
    }

    The message event to emit.

  Returns Promise<unknown>

  A promise that resolves when the event has been sent to the sink.

toolCall

• toolCall(
      e: Omit<ToolCallEvent, "sessionId" | "type" | "ts" | "level" | "ctx"> & {
          ctx?: TraceContext;
      },
  ): Promise<unknown>

  Emits a tool_call event, which represents a call to a tool.

  Parameters

  • e: Omit<ToolCallEvent, "sessionId" | "type" | "ts" | "level" | "ctx"> & {
        ctx?: TraceContext;
    }

    The tool call event to emit.

  Returns Promise<unknown>

  A promise that resolves when the event has been sent to the sink.

toolResult

• toolResult(
      e: Omit<ToolResultEvent, "sessionId" | "type" | "ts" | "level" | "ctx"> & {
          ctx?: TraceContext;
      },
  ): Promise<unknown>

  Emits a tool_result event, which represents the result of a tool call.

  Parameters

  • e: Omit<ToolResultEvent, "sessionId" | "type" | "ts" | "level" | "ctx"> & {
        ctx?: TraceContext;
    }

    The tool result event to emit.

  Returns Promise<unknown>

  A promise that resolves when the event has been sent to the sink.

usage

• usage(
      e: Omit<ModelUsageEvent, "sessionId" | "type" | "ts" | "level" | "ctx"> & {
          ctx?: TraceContext;
      },
  ): Promise<unknown>

  Emits a usage event, which contains information about token usage and cost.

  Parameters

  • e: Omit<ModelUsageEvent, "sessionId" | "type" | "ts" | "level" | "ctx"> & {
        ctx?: TraceContext;
    }

    The usage event to emit.

  Returns Promise<unknown>

  A promise that resolves when the event has been sent to the sink.

spanStart

• spanStart(opts: SpanStartOptions): SpanToken

  Starts a new span and returns a SpanToken that should be passed to spanEnd to complete the span. Any emitted event can reuse token.ctx to relate messages to this span.

  Parameters

  • opts: SpanStartOptions

    The options for starting the span.

  Returns SpanToken

  A SpanToken representing the in-flight span.

spanEnd

• spanEnd(
      token: SpanToken,
      end?: { status?: "error" | "ok"; attrs?: Record<string, unknown> },
  ): Promise<void>

  Finishes a span and emits a span event with the computed duration. The status of the span defaults to 'ok', but can be set to 'error' if the operation failed.

  Parameters

  • token: SpanToken

    The SpanToken returned from spanStart.

  • Optionalend: { status?: "error" | "ok"; attrs?: Record<string, unknown> }

    An optional object containing the status and attributes to add to the span.

  Returns Promise<void>

  A promise that resolves when the span event has been sent to the sink.

flush

• flush(): Promise<void>

  If the underlying sink is buffered, this method flushes any queued events to durable storage. This is a no-op for sinks that write immediately.

  Returns Promise<void>

  A promise that resolves when the flush is complete.

close

• close(): Promise<void>

  If the underlying sink is buffered, this method closes any open timers and flushes any remaining events. This is a no-op for sinks that write immediately.

  Returns Promise<void>

  A promise that resolves when the close operation is complete.