12.09.2025: Span Notes API

Span Notes API#

New dedicated endpoints for span notes enable open coding and seamless annotation integrations. Add notes to spans programmatically using the Phoenix client in both Python and TypeScript.

Python Client:

from phoenix.client import Clientclient = Client()client.spans.add_span_note(    span_id="your-span-id",    note="This span shows unexpected latency")

TypeScript Client:

import { addSpanNote } from "@arizeai/phoenix-client/spans";await addSpanNote({  spanNote: {    spanId: "your-span-id",    note: "This span shows unexpected latency"  }});

Use Cases:

Add contextual notes during debugging sessions
Annotate spans with human feedback
Build custom annotation pipelines and integrations
Document issues or observations for team collaboration

API Reference:#

Python Client

spans.add_span_note()

TypeScript Client

addSpanNote()