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PyPI · #4785 most downloaded on PyPI
AI Observability and Evaluation
Last release 4 days ago
01 Oct 2026
Ships on a steady schedule
a new release about every 8 days
Nearly every release is documented
notes for 60 of the last 60 stable releases
19 versions withdrawn
withdrawn after publishing
4 years old
700 releases · first in 2023
One column per quarter.
datagen: send each recorded application to its own project
tracing: show eval results in the trace tree
agents: mark bash tool spans as errors on non-zero exit codes
add gpt-6-sol, gpt-6-luna, and claude-opus-5-5 to the cost tables and the playground
agents: mount configured skills in MCP and PXI
datasets: editable dataset examples table
annotations: add GraphQL mutations for span, trace, and session notes
add Claude Code plugin and marketplace
client: add ATIF tracing to Harbor plugin
add MiniMax provider integration
server: move the MCP server to FastMCP 4 and the stateless protocol
server: replace deprecated json_encoders with an IsoDatetime serializer
add skill tools to mcp and use them in pxi
server: GET /v1/model_providers no longer returns custom providers or a next_cursor , and built-in entries expose provider rather than kind + provider
next_cursor, and built-in entries expose provider rather than kind + provider_key. Custom providers move to GET /v1/custom_model_providers. The endpoint is unreleased, so no published client is affected.20.3.0 (2026-08-16) Features traces: expression filter DSL
cost: update built-in model token prices
agents: emit a machine-readable approval decision on gated PXI tools
auth: support JWT client assertion for OAuth2 login
add semantic coloring to project metric tooltips
api: add REST endpoints for setting tags on experiments
add copy actions to session turns
app: make the Mastra snippet's OTLP path append idempotent
ui: collapse all but the last message in LLM spans
cli: make px setup's trace verdict the run's result (#14904) (253cfcf), closes #14876
server: OpenAI-compatible v1/chat/completions proxy with server-side credentials
add project evaluation metrics charts
add experiment evaluation metrics charts
agent: add Claude Opus 5 to the curated model list
client: add span_ids filter to get_spans in python and typescript clients
add evaluation metrics aggregation APIs
components: align span kind icon and timeline bar colors with token treatment
auth: negotiate HTTP/2 for OAuth2/OIDC provider requests
cli: improve server startup banner
cli: px setup mcp — register the Phoenix remote MCP server with a coding agent
api: REST CRUD for user and system API keys
sessions: use interval-overlap semantics for session time-range filters
agents: force tracing with debug env
ui: add session annotation editing in session details
ui: add dataset/prompt authorship columns, rename to updatedBy
clarify forced tool choice menus
agents: approval-gated annotation config tools + span-coding for PXI
evals: move PXI evals to pytest plugin
ui: improve PXI onboarding gate UX
agents: end-to-end PXI turn tracing from browser to backend
ui: user-selected metric charts above project tables
app: consistent disclosure arrows
app: add shift-click range selection to tables
add auth.md support for agent authentication discovery
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