Call schema reference

Reference for the Call object structure and properties

This page provides a reference for the Call object schema in W&B Weave. For information on querying calls, see Query and export calls.

Call properties

The table below outlines the key properties of a Call in Weave. For the complete implementation, see:

• class: CallSchema in the Python SDK.
• Interface: CallSchema in the TypeScript SDK.

Property	Type	Description
id	string (uuid)	Unique identifier for the call
project_id	string (optional)	Associated project identifier
op_name	string	Name of the operation (can be a reference)
display_name	string (optional)	User-friendly name for the call
trace_id	string (uuid)	Identifier for the trace this call belongs to
parent_id	string (uuid)	Identifier of the parent call
started_at	datetime	Timestamp when the call started
attributes	Dict[str, Any]	User-defined metadata about the call (read-only during execution)
inputs	Dict[str, Any]	Input parameters for the call
ended_at	datetime (optional)	Timestamp when the call ended
exception	string (optional)	Error message if the call failed
output	Any (optional)	Result of the call
summary	Optional[SummaryMap]	Post-execution summary information. You can modify this during execution to record custom metrics.
wb_user_id	Optional[str]	Associated W&B user ID
wb_run_id	Optional[str]	Associated W&B run ID
deleted_at	datetime (optional)	Timestamp of call deletion, if applicable

Property details

CallSchema properties play an important role in tracking and managing function calls:

• The id, trace_id, and parent_id properties help organize and relate calls within the system.
• Timing information (started_at, ended_at) support performance analysis.
• The attributes and inputs properties provide context for the call. Attributes are frozen once the call starts, so set them before invocation with weave.attributes. output and summary capture the results. -You can store metrics or other post-call values in the summary property. Modify call.summary during execution. Any values you add is merged with Weave’s computed summary data when the Call finishes.
  • Weave’s computed summary data:
    • costs: The total cost of the call based on LLM model usage data and token pricing data. For more information on cost calculation, see Track costs.
    • latency_ms: The duration, in milliseconds, elapsed between started_at and ended_at. null if status is RUNNING.
    • status: The execution status: SUCCESS, ERROR, RUNNING, DESCENDANT_ERROR (meaning the call itself succeeded but a descendant call errored).
• Integration with W&B is facilitated through wb_user_id and wb_run_id.

This comprehensive set of properties enables detailed tracking and analysis of function calls throughout your project.