# MLflow v3.15.0

- Product: MLflow (https://whatsnew.fyi/product/mlflow)
- Vendor: LF AI & Data
- Date: 2026-07-31
- Version: v3.15.0
- Original notes: https://github.com/mlflow/mlflow/releases/tag/v3.15.0
- Permalink: https://whatsnew.fyi/product/mlflow/releases/v3.15.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **added** — MCP Registry with semantic-versioned configs, promotable aliases, tags, auto-discovered tools, and ready-made connection instructions for Claude Code and .mcp.json
- **added** — MLflow Assistant now supports multiple LLM providers including Claude Code, Codex, and OpenAI-compatible/Gateway endpoints
- **added** — Sharable named views of the Runs table capturing columns, order, widths, filters, and sort
- **added** — Proxy-less artifact upload/download via presigned URLs for direct cloud storage transfers
- **added** — Multi-modal attachments in LLM judges with get_span_image tool to fetch and display images from trace spans
- **added** — Pydantic AI 2.x autologging support
- **added** — Per-endpoint budget policies in the AI Gateway
- **added** — SAP AI Core Orchestration v2 provider with extra_headers support
- **added** — Action recommendation for low-value issue detection result
- **added** — Search traces functionality in TypeScript SDK
- **added** — Per-tool cards with Monaco JSON editor and Format action in the Playground
- **added** — Redesigned Playground Tools settings with Add-tools entry flow
- **added** — Cursor model catalog with Auto and Composer 2.5 pricing
- **added** — Numeric assessment trace filters support
- **added** — mlflow agent setup command for single-prompt Assistant setup with secure API key storage
- **changed** — Assistant now displays live per-session token usage and estimated cost in the composer
- **changed** — UC model artifact download migrated to native temp-creds
- **changed** — UC model-registry client gated on native /api/2.1 endpoints
- **changed** — Tracing UI stopped eagerly prefetching full neighboring traces
- **fixed** — OpenTel parent context propagation in tracing
- **fixed** — Artifact direct download capability checks in UI
- **fixed** — Traces saved-view refresh on load across multiple windows
- **fixed** — UnauthorizedError constructor message
- **fixed** — Fall back to nested spans for Chat Sessions turn content
- **fixed** — Experiment GC cascades for traces and logged models
- **fixed** — Workspace-enabled tracking store crash-loop when default experiment is renamed
- **fixed** — Kubernetes auth token extraction for kubernetes-client 36+
- **fixed** — Assistant config refresh when leaving settings to prevent stale provider indicator
- **fixed** — Issue detection structured output schema
- **fixed** — mlflow.statsmodels flavor with MLFLOW_ALLOW_PICKLE_DESERIALIZATION guard
- **fixed** — Static prefixes preservation in notebook trace renderer URL
- **fixed** — Blank fields in run detail sidebar
- **fixed** — Reasoning content parts normalization for ChatAgentMessage in parse_message
- **fixed** — Evaluation Runs Actions dropdown remaining clickable when no runs are selected
- **fixed** — Truncated assistant streams surfaced as errors instead of silent done
- **fixed** — Experiment grants honored on artifacts-only servers when workspaces disabled
- **fixed** — Get-history-bulk-interval memory bounded by sampling metric history by row
- **fixed** — Artifact authorization enforcement on presigned download route in basic-auth
- **fixed** — Explicit expectations preservation in mlflow.genai.evaluate
- **fixed** — Portkey routing configuration support in the AI Gateway
- **fixed** — Input modal submission errors shown inline instead of transient toast in GenericInputModal

MLflow 3.15.0 includes several major features and improvements

###### Major New Features

- **🧩 [MCP Registry](https://mlflow.org/docs/latest/genai/mcp-registry/)**: A centralized catalog for registering, versioning, and sharing Model Context Protocol servers — with semantic-versioned configs, promotable aliases, tags, auto-discovered tools, and ready-made connection instructions for Claude Code and `.mcp.json`. Manage it from the UI, REST API, or Python!
- **🤖 MLflow Assistant enhancements**: The in-app AI assistant now supports multiple LLM providers (Claude Code, Codex, and OpenAI-compatible/Gateway endpoints) chosen from a single settings page, displays live per-session token usage and estimated cost in the composer, and is easier to set up — `mlflow agent setup` can enable it in one prompt, with API keys stored securely in the Gateway's LLM Connections.
- **🗂️ Sharable table views**: Save named views of the Runs table — capturing columns, order, widths, filters, and sort — and share them by URL.
- **⚡ Proxy-less artifact upload/download via presigned URLs**: Large artifact transfers can now bypass the tracking server and talk directly to cloud storage (e.g. S3) through presigned URLs, cutting server load and timeouts on big files. We fall back to proxied transfer automatically for backward compatibility.
- **🖼️ Multi-modal attachments in LLM judges**: `{{ trace }}` judges created with `make_judge()` can now _see_ images captured in trace spans via a new `get_span_image` tool, which fetches attachments as base64 data URLs and passes them to multimodal models (Anthropic, Gemini, and OpenAI-compatible via litellm) — enabling evaluation of vision tasks, screenshots, and other visual content.

###### Other Assorted Features & Improvements:

- [Tracing / Tracking] Add Pydantic AI 2.x autologging support (#24721, @B-Step62)
- [Tracing / UI] [3/3] Add action recommendation for low-value issue detection result (#24580, @B-Step62)
- [Gateway] Support per-endpoint budget policies in the AI Gateway (#24370, @joelrobin18)
- [Evaluation / Gateway] Add `sap-ai-core:/` provider for SAP AI Core Orchestration v2 with `extra_headers` support (#24356, @shivamxtech)
- [Model Registry] [Model Registry] Migrate UC model artifact download to native temp-creds (#24576, @AknA13)
- [Gateway / Tracing / UI] [2/3] Simplify issue detection start modal (#24579, @B-Step62)
- [Tracing / UI] [1/3] Run issue detection in the background (#24578, @B-Step62)
- [Tracing] [BUG] Fix otel parent context propagation (#24444, @iyashk)
- [Model Registry] [Model Registry] Gate UC model-registry client on native `/api/2.1` endpoints (#24517, @AknA13)
- [Docs / Tracking] Enable artifacts-only mode with workspaces (#24452, @kramaranya)
- [Tracing / UI] Stop eagerly prefetching full neighboring traces in tracing UI (#24411, @DaoDaoNoCode)
- [Docs / Gateway] Authenticate OpenAI-protocol coding agents through the RBAC gateway (#24294, @joshuawong-db)
- [Tracing] feat: add search traces to typescript sdk (#23660, @WUMIKE233)
- [Prompts / UI] Add per-tool cards with a Monaco JSON editor and Format action to the Playground (#24129, @tanghaoji)
- [Prompts / UI] Redesign Playground `Tools` settings with an Add-tools entry flow (#24102, @tanghaoji)
- [] feat: add Cursor model catalog with Auto and Composer 2.5 pricing (#24078, @TomeHirata)
- [Tracing / Tracking] Support numeric assessment trace filters (#23948, @tanghaoji)

Bug fixes:

- [Tracing] Compute `mlflow.llm.cost` for Claude Code plugin traces on Databricks (#24416, @harupy)
- [UI] Fix artifact direct download capability checks in UI (#24748, @B-Step62)
- [Tracing / UI] Refresh traces saved-view on load across multiple windows (#24746, @joshuawong-db)
- [UI] Fix UnauthorizedError constructor message (#24729, @mihir2921)
- [UI] Fall back to nested spans for Chat Sessions turn content (#24703, @MannXo)
- [Tracing / Tracking] Fix experiment GC cascades for traces and logged models

_[Truncated at 4000 characters — full notes: https://github.com/mlflow/mlflow/releases/tag/v3.15.0]_