Arize Phoenix MCP Server for Claude
Inspect LLM traces and spans, manage prompts, explore datasets, and review evaluation experiments from Claude — with the official Arize Phoenix MCP server, built into the open-source Phoenix AI observability platform.
Open the source and read safety notes before installing.
Safety notes
- The `write` and upsert tools can create or modify prompts and add dataset examples — review Claude's proposed changes before confirming.
- For self-hosted deployments, ensure your Phoenix instance is accessible from the machine running the MCP server.
Privacy notes
- LLM traces (including prompts and completions), evaluation annotations, session data, datasets, and experiment results from your Phoenix workspace are surfaced in Claude's context.
- Your `PHOENIX_API_KEY` is passed as an environment variable — store it in a secrets manager rather than plaintext shell config.
Prerequisites
- An Arize Phoenix account (cloud at app.phoenix.arize.com) or self-hosted Phoenix instance.
- A Phoenix API key from your account settings.
- Node.js 18+ for `npx`.
- An MCP client such as Claude Code or Claude Desktop.
Schema details
- Install type
- cli
- Troubleshooting
- No
- Scope
- Source repo
- Estimated setup
- 5 minutes
- Difficulty
- beginner
- Website
- https://arize.com/phoenix/
Full copyable content
{
"mcpServers": {
"phoenix": {
"command": "npx",
"args": ["-y", "@arizeai/phoenix-mcp@latest"],
"env": {
"PHOENIX_HOST": "https://app.phoenix.arize.com",
"PHOENIX_API_KEY": "your-api-key"
}
}
}
}About this resource
Overview
The Arize Phoenix MCP Server is the official Model Context Protocol server for Arize Phoenix, the open-source AI observability platform. It connects Claude directly to your Phoenix workspace — traces, spans, prompts, datasets, sessions, and evaluation experiments — through a comprehensive set of tools for LLM debugging and evaluation.
Phoenix supports both cloud (app.phoenix.arize.com) and self-hosted deployments, so trace data can stay entirely within your own infrastructure.
Key capabilities
- Traces & spans — retrieve LLM execution traces, individual spans, and annotations.
- Projects — list projects, get project-level statistics.
- Sessions — explore conversation sessions and multi-turn flows.
- Prompt management — list prompts, retrieve versions, and upsert new prompt definitions.
- Datasets — discover datasets and add new examples.
- Experiments — access experiment runs and LLM-analyzed evaluation results.
- Annotation configs — list available evaluation configurations and their schemas.
How it compares
| Server | Traces & spans | Prompt library | Datasets | Experiments | Auth |
|---|---|---|---|---|---|
| Arize Phoenix MCP | Yes | Yes | Yes | Yes | API key |
| Opik MCP | Yes | Yes | Yes | Yes | API key |
| LangSmith MCP | Yes | Yes | Yes | Yes | API key |
| Weights & Biases MCP | Yes | Limited | Yes | Yes | API key |
Arize Phoenix is fully open-source (Apache-2.0) with a first-class self-hosted deployment path, making it well-suited for teams with strict data residency requirements.
Installation
Claude Code
claude mcp add phoenix \
-e PHOENIX_HOST=https://app.phoenix.arize.com \
-e PHOENIX_API_KEY=your-api-key \
-- npx -y @arizeai/phoenix-mcp@latest
Get your API key from Phoenix account settings → API Keys.
Claude Desktop
{
"mcpServers": {
"phoenix": {
"command": "npx",
"args": ["-y", "@arizeai/phoenix-mcp@latest"],
"env": {
"PHOENIX_HOST": "https://app.phoenix.arize.com",
"PHOENIX_API_KEY": "your-api-key"
}
}
}
}
Self-hosted Phoenix
Set PHOENIX_HOST=http://localhost:6006 (or your instance URL) instead of the cloud endpoint.
Optional configuration
Set PHOENIX_PROJECT=my-project to default tool calls to a specific project.
Requirements
- An Arize Phoenix account (cloud or self-hosted).
- A Phoenix API key.
- Node.js 18+ (for
npx). - An MCP client (Claude Code or Claude Desktop).
Security
- API key scoped to your Phoenix workspace.
- Self-hosted deployment keeps all trace and evaluation data within your infrastructure.
Source Verification Notes
Verified on 2026-06-18:
- GitHub repo
Arize-ai/phoenixcontains the MCP package atjs/packages/phoenix-mcp/. The README documents thenpx @arizeai/phoenix-mcp@latestinstall,PHOENIX_HOST/PHOENIX_API_KEYenv vars, and the full tool surface (prompts, projects, traces, sessions, datasets, experiments). - Phoenix documentation at
arize.com/docs/phoenixcovers the observability platform, tracing concepts, and evaluation workflows.
Source citations
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How it compares
Arize Phoenix MCP Server for Claude side by side with 3 alternatives on trust, install, platform support, and disclosed safety notes — all from reviewed registry metadata.
| Field | Arize Phoenix MCP Server for Claude Inspect LLM traces and spans, manage prompts, explore datasets, and review evaluation experiments from Claude — with the official Arize Phoenix MCP server, built into the open-source Phoenix AI observability platform. Open dossier | Opik MCP Server for Claude Debug, evaluate, and monitor LLM applications from Claude — read traces and spans, score outputs, save prompts, run evaluation experiments, and query project metrics — with the official Opik MCP server by Comet. Open dossier | LangSmith MCP Server for Claude Connect Claude to LangSmith — retrieve conversation threads and traces, fetch and push prompts, browse evaluation datasets and experiments, and access billing usage — with the official LangSmith Model Context Protocol server from LangChain. Open dossier | OpenTelemetry MCP Server for Claude Analyze distributed traces and LLM observability data from Claude — search traces and spans, find errors, list services, analyze LLM token usage, identify slow LLM operations, and discover AI model usage patterns — with the OpenTelemetry MCP server supporting Jaeger, Grafana Tempo, and Traceloop backends. Open dossier |
|---|---|---|---|---|
| Trust | ||||
| Install risk | Review first | Review first | Review first | Review first |
| Notes | Safety ✓ Privacy ✓ | Safety ✓ Privacy ✓ | Safety ✓ Privacy ✓ | Safety ✓ Privacy ✓ |
| Category | mcp | mcp | mcp | mcp |
| Source | source-backed | source-backed | source-backed | source-backed |
| Author | Arize AI | Comet | LangChain | Traceloop |
| Added | 2026-06-18 | 2026-06-18 | 2026-06-18 | 2026-06-18 |
| Platforms | Claude CodeCodexCursorClaude Desktop | Claude CodeClaude Desktop | Claude CodeClaude Desktop | Claude CodeClaude Desktop |
| Source repo | — | — | — | — |
| Safety notes | ✓The `write` and upsert tools can create or modify prompts and add dataset examples — review Claude's proposed changes before confirming. For self-hosted deployments, ensure your Phoenix instance is accessible from the machine running the MCP server. | ✓The `write` tool can create traces, spans, scores, and prompts in your Opik workspace — review any write operations before confirming. The `run_experiment` tool executes evaluation experiments end-to-end, which may incur LLM API costs depending on your experiment configuration. | ✓The server runs locally via `uvx` and connects to the LangSmith cloud API using your API key. The server provides read access to your traces, prompts, datasets, and experiments; it can also push prompts (write). Trace data may contain sensitive LLM inputs and outputs from your production systems — treat retrieved traces as confidential. | ✓All tools are read-only — the server queries trace data but does not modify your application or tracing backend. Trace data may contain sensitive information (request parameters, user IDs, SQL queries) — ensure Claude has appropriate access to this data. |
| Privacy notes | ✓LLM traces (including prompts and completions), evaluation annotations, session data, datasets, and experiment results from your Phoenix workspace are surfaced in Claude's context. Your `PHOENIX_API_KEY` is passed as an environment variable — store it in a secrets manager rather than plaintext shell config. | ✓LLM traces (including prompts and completions), evaluation scores, experiment results, and prompt library contents from your Opik workspace are surfaced in Claude's context. Your `OPIK_API_KEY` is passed as an environment variable — store it in a secrets manager rather than plaintext shell config. | ✓Conversation threads, prompt content, run inputs/outputs, and dataset examples are surfaced in Claude's context. LANGSMITH_API_KEY is a secret — store it in your environment or MCP client config, never in repositories. | ✓Distributed trace content including service names, operation names, error messages, HTTP parameters, and LLM prompt/response metadata may be surfaced in Claude's context. For Traceloop backend, `BACKEND_API_KEY` is required and grants access to your Traceloop organization's trace data. |
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