Flagr MCP Server

A Model Context Protocol (MCP) server for managing Flagr feature flags via Cursor IDE.

Features

• List and inspect flags - View all flags, filter by key/tags/enabled status
• Create flags - Create new feature flags with descriptions and tags
• Manage segments - Add segments with rollout percentages
• Add constraints - Target specific users by role, userId, environment, etc.
• Set distributions - Configure A/B test percentages

Installation

Via npx (Recommended)

Add to your ~/.cursor/mcp.json:

{
  "mcpServers": {
    "flagr": {
      "command": "npx",
      "args": ["-y", "flagr-mcp"],
      "env": {
        "FLAGR_URL": "https://your-flagr-instance.com"
      }
    }
  }
}

Replace https://your-flagr-instance.com with your Flagr API URL.

Available Tools

| Tool | Description | |------|-------------| | list_flags | List all flags with optional filters (enabled, key, tags) | | get_flag | Get detailed info about a specific flag | | create_flag | Create a new feature flag | | update_flag | Update flag properties (enable/disable, description) | | delete_flag | Delete a feature flag | | create_segment | Add a segment to a flag | | update_segment | Update segment properties | | delete_segment | Remove a segment | | create_constraint | Add a constraint to a segment | | delete_constraint | Remove a constraint | | create_variant | Add a variant to a flag | | delete_variant | Remove a variant | | set_distribution | Set variant distribution percentages |

Example Usage in Cursor

Once configured, you can ask Cursor things like:

• "List all feature flags"
• "Create a flag called NewFeature with description 'My new feature'"
• "Add a segment to NewFeature for admin users with 100% rollout"
• "Enable flag NewFeature"

Constraint Operators

| Operator | Description | Example | |----------|-------------|---------| | EQ | Equals | role EQ "admin" | | NEQ | Not equals | environment NEQ "production" | | IN | In list | userId IN "123,456,789" | | NOTIN | Not in list | userId NOTIN "123" | | CONTAINS | Contains substring | email CONTAINS "@example" | | EREG | Regex match | userId EREG "^user_.*" | | GT, GTE, LT, LTE | Numeric comparisons | priority GTE "2" |

Environment Variables

| Variable | Required | Description | |----------|----------|-------------| | FLAGR_URL | Yes | Flagr API base URL (e.g., https://flagr.example.com) |

License

MIT