GrowthBook MCP Server for Claude

Overview

The GrowthBook MCP Server is the official Model Context Protocol server from GrowthBook, the open-source A/B testing and feature flag platform. It connects Claude directly to your GrowthBook workspace — listing and creating experiments, managing feature flags, reviewing experiment results, and more. Permissions follow your API key's access level. Licensed under MIT.

Supports both GrowthBook Cloud (api.growthbook.io) and self-hosted instances via the GB_API_URL and GB_APP_ORIGIN environment variables.

Key capabilities

• Experiments — list experiments, get details and results, create new A/B tests.
• Feature flags — list feature flags, create new flags, update targeting rules.
• Self-hosted support — point to any GrowthBook instance via GB_API_URL.
• Custom headers — add tenant IDs, auth tokens, or proxy headers via GB_HTTP_HEADER_<NAME> environment variables.

How it compares

GrowthBook is the only open-source option with native A/B experiment management alongside feature flags — giving full control over the experiment lifecycle from Claude.

Installation

Claude Code

claude mcp add growthbook \
  -e GB_API_KEY=your-api-key \
  -e GB_EMAIL=you@example.com \
  -- npx @growthbook/growthbook-mcp

Claude Desktop

{
  "mcpServers": {
    "growthbook": {
      "command": "npx",
      "args": ["@growthbook/growthbook-mcp"],
      "env": {
        "GB_API_KEY": "your-api-key",
        "GB_EMAIL": "you@example.com"
      }
    }
  }
}

Self-hosted GrowthBook

{
  "env": {
    "GB_API_KEY": "your-api-key",
    "GB_EMAIL": "you@example.com",
    "GB_API_URL": "https://your-growthbook.example.com/api",
    "GB_APP_ORIGIN": "https://your-growthbook.example.com"
  }
}

Requirements

• A GrowthBook account with an API key and your account email.
• Node.js with npx.
• An MCP client (Claude Code or Claude Desktop).

Security

• Capabilities are scoped by your API key's permissions — use a least-privilege key.
• Feature flags and experiments may affect production; review before creating or modifying.

Source Verification Notes

Verified on 2026-06-18:

• Official GitHub repository growthbook/growthbook-mcp (MIT) documents the @growthbook/growthbook-mcp npm package, GB_API_KEY/GB_EMAIL/GB_API_URL/ GB_APP_ORIGIN configuration, GB_HTTP_HEADER_* custom headers, and the official docs link.
• GrowthBook documentation at docs.growthbook.io/integrations/mcp (HTTP 200) covers setup and available capabilities.
• Claude Code MCP documentation at code.claude.com/docs/en/mcp describes the stdio connector pattern used above.