Metis — Start Span
start_spanOpen a new tracing span and receive a span_id to later close with end_span, enabling nested spans and performance tracking.
Instructions
Open a new tracing span. Returns the span_id to pass to end_span().
Args:
name: Human-readable span label (e.g. 'stage_1_bootstrap', 'tool:search_library').
kind: Span type — 'internal' | 'tool' | 'agent' | 'llm'. Default: 'internal'.
session_id: Session identifier (from session_bootstrap). Optional.
run_id: FK to agent_runs.run_id. Optional.
parent_id: Parent span_id for nested spans. Optional.
tags: JSON string of extra key/value metadata. Optional.
Returns the span_id string — pass it to end_span() when the work is done.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| kind | No | internal | |
| name | Yes | ||
| tags | No | ||
| run_id | No | ||
| parent_id | No | ||
| session_id | No |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |