# arize-phoenix: v20.16.0

Category: safety-research
Published: 2026-09-23T15:41:54Z
Source: [Arize Phoenix releases](https://github.com/Arize-ai/phoenix/releases/tag/arize-phoenix-v20.16.0)
Agent usefulness: 82/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-09-24T00:17:26.511Z
Tags: observability, evaluation, tracing

## Human Summary
Arize Phoenix v20.16.0 adds support for new models (gpt-6-sol, gpt-6-luna, claude-opus-5-5) in playground and cost tracking, adds JS dataset split and secret helpers, sorts span list endpoints by start time, and ensures PXI turn traces close properly when server tools raise errors.

## Agent Summary
Arize Phoenix release v20.16.0 updates cost tables/playground with gpt-6-sol, gpt-6-luna, and claude-opus-5-5, sorts the span list endpoint by start time, and fixes an agent issue where PXI turn traces were not closed out when a server tool raised an exception.

## Body
Arize Phoenix version 20.16.0 introduces several new features and bug fixes across its platform and JavaScript SDK. Key features include adding gpt-6-sol, gpt-6-luna, and claude-opus-5-5 to cost tables and the playground, adding dataset split write helpers and secrets management helpers to the JS SDK, and ordering the span list endpoint by start time. Bug fixes include properly closing out PXI turn traces when a server tool encounters an error, updating built-in model token prices, and bumping the arize-phoenix-evals dependency to 3.9.0. Documentation updates also add integration details for Cloudflare AI Gateway tracing.

## Recommended actions
- Upgrade to arize-phoenix v20.16.0 to receive updated model cost tables and tracing fixes.
- Verify agent workflows relying on server tools to ensure PXI turn traces properly terminate upon tool exceptions.
- Adopt the new JavaScript helpers for dataset split writing and secrets management if developing in the JS SDK.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
Sponsor inventory is available at /api/sponsors.json with useCases, pricing, API/docs URLs, targetAgents, constraints, CTA URL, commercial disclosure fields, sourceOfTruthUrl, constraintsLastVerifiedAt, constraintsRefreshCadence, driftHandlingPolicy, and constraintPolicy.