MCP

The ZeroEval MCP server lets AI agents inspect traces, manage judges and prompts, submit feedback, run optimizations, and deploy to production, all without leaving the agent context. It speaks the Model Context Protocol, so any MCP-compatible client (Cursor, Claude Code, Windsurf, etc.) can connect directly.

Setup

The fastest way to get started is to point your MCP client at the hosted server. No installation required.

Cursor

Add this to your Cursor MCP settings (.cursor/mcp.json):

{
  "mcpServers": {
    "zeroeval": {
      "url": "https://mcp.zeroeval.com/mcp",
      "headers": {
        "Authorization": "Bearer <your-project-api-key>"
      }
    }
  }
}

Claude Code

claude mcp add zeroeval --transport http https://mcp.zeroeval.com/mcp \
  --header "Authorization: Bearer <your-project-api-key>"

Other MCP clients

Any client that supports HTTP transport works. Set the server URL to https://mcp.zeroeval.com/mcp and pass your project API key in the Authorization: Bearer <key> header.

Get your project API key from the ZeroEval dashboard under Settings → API Keys.

Resources

The server exposes two MCP resources for introspection:

URI	Description
`config://server-context`	Redacted server config: auth mode, base URL, project scope, and feature flags
`docs://capabilities`	Canonical tool and resource inventory with annotations and output contract summary

Tools

Read tools

Read tools are safe to call at any time. They do not modify state.

Tool	Description
`list-traces`	List recent traces
`get-trace`	Get a trace with its spans
`list-judges`	List all judges
`get-judge`	Get judge details and linkage state
`list-judge-evaluations`	List evaluations from a judge
`get-judge-criteria`	Get scoring criteria for a judge
`list-prompts`	List all prompts
`get-prompt`	Get a prompt at a specific version or tag
`list-prompt-versions`	List all versions of a prompt
`list-optimization-runs`	List optimization runs for a task
`get-optimization-run`	Get run details with candidate prompt and metrics
`get-project-summary`	High-level project monitoring summary

Write tools

All write tools require confirm: true in the request and are annotated with destructiveHint: true so MCP clients can prompt for user approval before calling.

Tool	Description
`create-judge`	Create a new judge
`link-judge-to-prompt`	Link a judge to a prompt
`unlink-judge-from-prompt`	Remove a judge’s prompt link
`create-judge-feedback`	Submit feedback on a judge evaluation
`create-prompt-feedback`	Submit feedback on a prompt completion
`start-prompt-optimization`	Start a prompt optimization run
`start-judge-optimization`	Start a judge optimization run
`cancel-optimization-run`	Cancel a running optimization

Deploy

Production deploys always require two steps:

Preview: Call preview-optimization-deploy with the run ID. This verifies the run succeeded, summarizes the candidate vs current production, and returns a time-limited confirmation receipt.
Deploy: Call deploy-optimization-run with confirm: true and the receipt from preview. The server re-reads current state and rejects the deploy if anything drifted since the preview.

Tool	Description
`preview-optimization-deploy`	Preview what deploying a run would do (read-only)
`deploy-optimization-run`	Deploy a succeeded run to production (requires receipt + confirm)

Proposal tools

Proposal tools are read-only helpers that gather evidence or prepare the exact next mutating call without executing it.

Tool	Description
`investigate-prompt-issues`	Gather evidence about prompt state and recommend next steps
`investigate-judge-issues`	Gather evidence about judge state and recommend next steps
`prepare-prompt-optimization`	Propose the exact `start-prompt-optimization` call to make
`prepare-judge-optimization`	Propose the exact `start-judge-optimization` call to make

Tracing quickstart

Get your first trace in under 5 minutes

Prompt setup

Add ze.prompt() to your codebase

Judges

How calibrated judges evaluate your production traffic

CLI

Manage traces, prompts, and judges from your terminal

Tracing

Prompts

Feedback

Helpers

Setup

Cursor

Claude Code

Other MCP clients

Resources

Tools

Read tools

Write tools

Deploy

Proposal tools

Tracing quickstart

Prompt setup

Judges

CLI

​Setup

​Cursor

​Claude Code

​Other MCP clients

​Resources

​Tools

​Read tools

​Write tools

​Deploy

​Proposal tools

Tracing quickstart

Prompt setup

Judges

CLI

Setup

Cursor

Claude Code

Other MCP clients

Resources

Tools

Read tools

Write tools

Deploy

Proposal tools