Unleash MCP Server for Claude

Overview

The Unleash MCP Server is the official Model Context Protocol server from Unleash, the open-source feature flag management platform. It guides Claude through the full feature flag lifecycle — evaluating whether a change needs a flag, detecting duplicates, creating flags, setting rollout strategies, toggling environments, and generating cleanup instructions when a flag is ready to retire. Licensed under MIT.

Supports both the local npx @unleash/mcp stdio mode and remote HTTP to your Unleash instance's built-in MCP endpoint (experimental).

Key capabilities

• Change evaluation — evaluate_change scores risk and recommends whether a feature flag is appropriate for a given code change.
• Duplicate detection — detect_flag scans existing flags before creating to prevent duplicates and encourage reuse.
• Flag creation — create_flag creates a flag with proper validation and typing following Unleash best practices.
• Code wrapping — wrap_change generates language-specific code to wrap a change in the newly created flag.
• Rollout management — set_flag_rollout configures gradual rollout strategies.
• Environment control — toggle_flag_environment enables or disables a flag per environment.
• Cleanup — cleanup_flag generates step-by-step instructions for safely removing a flag.

Tools

How it compares

Unleash's cleanup_flag tool generates actionable cleanup instructions — unique among feature flag MCP servers — guiding the full flag retirement workflow from evaluation to removal.

Installation

Claude Code (local)

claude mcp add unleash \
  --env UNLEASH_BASE_URL=https://your-instance.unleash.cloud \
  --env UNLEASH_PAT=your-personal-access-token \
  -- npx -y @unleash/mcp@latest --log-level error

Claude Desktop

{
  "mcpServers": {
    "unleash": {
      "command": "npx",
      "args": ["-y", "@unleash/mcp@latest", "--log-level", "error"],
      "env": {
        "UNLEASH_BASE_URL": "https://your-instance.unleash.cloud",
        "UNLEASH_PAT": "your-personal-access-token"
      }
    }
  }
}

Remote HTTP (experimental)

claude mcp add unleash https://your-instance.unleash.cloud/api/admin/mcp --transport http

Requirements

• An Unleash instance (cloud or self-hosted) with a personal access token.
• Node.js 22+.
• An MCP client (Claude Code or Claude Desktop).

Security

• Use a least-privilege PAT scoped to the projects you need.
• toggle_flag_environment can affect production traffic — confirm before executing.

Source Verification Notes

Verified on 2026-06-18:

• Official GitHub repository Unleash/unleash-mcp (MIT) documents the @unleash/mcp npm package, UNLEASH_BASE_URL/UNLEASH_PAT configuration, Node.js 22+ requirement, all 11 tools, the Claude Code install command, the four-step core workflow (evaluate → detect → create → wrap), and the experimental remote HTTP mode.
• Unleash documentation at docs.getunleash.io/integrations/mcp (HTTP 200) covers setup and tool reference.
• Claude Code MCP documentation at code.claude.com/docs/en/mcp describes the connector pattern used above.