@flaggr/mcp-server

Model Context Protocol (MCP) server for Flaggr — manage feature flags from AI assistants like Claude, Cursor, and VS Code Copilot.

Installation

npm install -g @flaggr/mcp-server

Authentication

The Flaggr MCP server supports three flexible authentication methods:

1. Auto-Discovery via Flaggr CLI (~/.flaggr/config.json): If you have already logged in via flaggr login, the MCP server automatically reads your stored credentials with zero manual configuration.
2. Interactive Browser Login via MCP Tool (login): AI assistants can call the login tool directly. It will open your browser to the Flaggr authorization page, prompt you to select an organization/project, and securely save the minted credentials locally.
3. Direct Token via Environment or MCP Tool: Pass FLAGGR_API_TOKEN in your environment or call login({ token: "fgr_..." }).

Claude Desktop Configuration

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "flaggr": {
      "command": "npx",
      "args": ["@flaggr/mcp-server"],
      "env": {
        "FLAGGR_API_URL": "https://flaggr.dev"
      }
    }
  }
}

(If you have logged in via flaggr login, FLAGGR_API_TOKEN can be omitted!)

Tools

| Tool | Description | |------|-------------| | get_auth_status | Check authentication status, current project, and connection | | login | Authenticate via browser OAuth flow or supply an API token | | logout | Clear in-memory and stored credentials | | list_projects | List all projects | | get_project | Get project details | | list_services | List services in a project | | list_flags | List flags for a service | | get_flag | Get flag configuration | | create_flag | Create a new flag | | update_flag | Update flag settings | | toggle_flag | Enable/disable a flag | | delete_flag | Delete a flag | | evaluate_flag | Evaluate a flag with context and targeting | | get_flag_toggle_impact | Post-toggle safety, drift metrics, error rate delta, P99 latency shift, and automated health assessment | | get_flag_metrics | Detailed evaluation volume, error rates, percentiles, breakdowns, and toggle impact | | get_project_health | Aggregated project health score, per-service breakdown, top issues | | get_evaluation_heatmap | Project-wide flag x service evaluation usage heatmap | | get_audit_log | Audit logs with deep path-scoped diffs and actor attribution | | get_flag_history | Flag revision history and version diffs | | measure_round_trip | True real-time SSE stream propagation and RTT latency measurement | | watch_flag_updates | Real-time SSE flag event stream listener | | get_trace | OpenTelemetry distributed trace waterfall and hotspot diagnosis | | get_flag_traces | Query recent evaluation traces | | trace_flag_evaluation | Evaluate flag on-demand and produce flamechart waterfall | | create_targeting_rule | Add targeting rule | | delete_targeting_rule | Remove targeting rule | | create_override | Create context override | | delete_override | Remove override | | check_system_health | Platform and telemetry health check | | get_flag_health | Flag health score | | get_evaluation_stats | Service evaluation metrics | | get_flag_impact | Pre-change impact analysis | | create_experiment | Set up A/B test | | list_experiments | List experiments | | get_experiment | Get experiment details | | stop_experiment | End an experiment | | list_sites | List all sites and web properties within a service or project | | get_site | Get site configuration details, domain, and linked feature flags | | create_site | Onboard a new site with domain and initial flags | | update_site | Update site domain, environment, description, or linked flags | | delete_site | Delete an onboarded site | | link_flag_to_site | Link a feature flag to a site for telemetry tracking and SDK evaluation | | unlink_flag_from_site | Unlink a feature flag from a site | | get_flag_linked_sites | List all sites in a service that are linked to a specific flag |

Resources

• flaggr://auth/status — Current authentication state and project binding
• flaggr://projects — All projects
• flaggr://project/{slug}/flags — Flags for a project
• flaggr://site/{siteId} — Site configuration, domain, and linked flags
• flaggr://flag/{key}/health — Flag health score
• flaggr://flag/{key}/toggle-impact — Post-toggle safety, drift metrics, and before/after comparison

Prompts

• verify_toggle_safety — Verify post-toggle safety, drift, and performance impact
• gradual_rollout — Plan a staged percentage rollout
• ab_test_setup — Design an A/B test experiment
• targeting_strategy — Build targeting rules for a use case

Environment Variables

| Variable | Required | Description | |----------|----------|-------------| | FLAGGR_API_URL | Yes | Flaggr instance URL | | FLAGGR_API_TOKEN | Yes | API token with appropriate scopes |

Documentation

• MCP integration guide
• API tokens