Archived: MIGRATED TO OPENFEATURE ORG

OpenFeature MCP Local Server (stdio)

Warning

This project is in active development.

Related MCP server: MCP OpenAPI Proxy

Features

A local Model Context Protocol (MCP) server that provides OpenFeature SDK installation guidance and Open Feature Remote Evaluation Protocol (OFREP) over stdio.

• OpenFeature SDK Installation Guides: Fetch installation prompts for various OpenFeature SDKs

• MCP stdio Transport: Intended for local usage by MCP-compatible clients

Configure your AI client (local)

Cursor

Add to ~/.cursor/mcp_settings.json:

VS Code (Continue)

Add to .continue/config.json:

Claude Code (CLI)

Add the server via CLI:

Then manage the connection in the CLI with /mcp.

Windsurf

In the "Manage MCP servers" raw config, add:

Claude Desktop

Edit your Claude Desktop config and add:

Restart Claude Desktop after saving.

NPM Global install (optional)

If you prefer a global install instead of NPX:

Now in your MCP config use openfeature-mcp as the command:

All logs are written to stderr. The MCP protocol messages use stdout.

Available Tools

install_openfeature_sdk

Fetches Markdown instructions for installing the OpenFeature SDK for a given technology. Optionally augments the prompt with installation guidance for one or more feature flag providers.

Parameters:

• technology (string enum): One of the supported technologies listed below

• providers (string array, optional): Zero or more provider identifiers. If present, adds provider-specific installation notes to the prompt (or removes placeholder sections when empty).

Supported Technologies:

The technologies list is build from the avaliable prompts/*.md, updated automatically using scripts/build-prompts.js

• android

• dotnet

• go

• ios

• java

• javascript

• nestjs

• nodejs

• php

• python

• react

• ruby

Supported Providers:

The provider list is sourced automatically from the OpenFeature open-feature/openfeature.dev repo; newly added providers there become available here without manual edits. See scripts/build-providers.js for details.

ofrep_flag_eval

Evaluate feature flags via OpenFeature Remote Evaluation Protocol (OFREP). If flag_key is omitted, performs bulk evaluation.

References: open-feature/protocol, OFREP OpenAPI spec

Parameters (all optional unless noted):

• base_url (string, optional): Base URL of your OFREP-compatible flag service. If omitted, the server uses env/config (see below).

• flag_key (string, optional): If provided, calls single flag evaluation: /ofrep/v1/evaluate/flags/{key}. If omitted, calls bulk: /ofrep/v1/evaluate/flags.

• context (object, optional): Evaluation context, e.g. { "targetingKey": "user-123", ... }.

• etag (string, optional): For bulk requests, sent as If-None-Match to enable 304 caching semantics.

• auth (object, optional): Inline auth for this call only.

  • bearer_token (string, optional): Sets Authorization: Bearer <token>.

  • api_key (string, optional): Sets X-API-Key: <key>.

Auth and base URL resolution (priority):

1. Tool call args: base_url, auth.bearer_token, auth.api_key

2. Environment variables: OPENFEATURE_OFREP_BASE_URL (or OFREP_BASE_URL), OPENFEATURE_OFREP_BEARER_TOKEN (or OFREP_BEARER_TOKEN), OPENFEATURE_OFREP_API_KEY (or OFREP_API_KEY)

3. Config file: ~/.openfeature-mcp.json (override with OPENFEATURE_MCP_CONFIG_PATH)

Example ~/.openfeature-mcp.json:

Notes:

• Bulk requests may return ETag. Pass it back via etag to leverage 304 Not Modified.

• Either bearer token or API key can be supplied; both are supported by the spec.

Development

Prerequisites

• Node.js 18+

Setup

1. Install dependencies:

   npm install

2. Add or edit install guides in the prompts/ folder (Markdown). These are bundled at build time.

3. Build prompts bundle:

   npm run build-prompts

4. Build TypeScript:

   npm run build

5. Run locally (binary entrypoint):

   node dist/cli.js