"An MCP to access OpenAI's RAG system via API" matching MCP servers:

Gateway connector between LLM agents and world data, providing access to financial market prices, macroeconomic indicators, and news through a bundled endpoint catalog.

Official MCP server for Shipmail, enabling agents to manage domains, mailboxes, messages, threads, webhooks, and suppressions via natural language.

The best free social media publishing and scheduling API. Publish to 11 platforms from a single API call. Schedule posts, upload media, track analytics, and automate your social media workflow.

Exposes structured documentation for 200+ Trimble Connect API endpoints and provides tools for AI-assisted development of Trimble Connect extensions and applications.

MCP server that resolves postal/ZIP codes to place names, states, and coordinates using Zippopotam.us. Free, no API key required.

Enables real-time domain registration lookups via RDAP, including availability, expiration, and registrar details, with no API key required. Supports natural language queries like 'is example.com available?' or 'when does example.com expire?'.

Provides live product search, offer comparison, and price history retrieval from BestPrice.gr through three read-only tools, enabling AI applications to query shopping data without an API key.

Enables users to draw GIS geometry on an interactive map and get clean, validated GeoJSON to hand off to other GIS MCP servers such as FEMA flood screening and USGS hydrography.

Gives Claude read-only access to your ESPN fantasy football team, including roster, weekly matchup, free agents, and player profiles.

Enables currency conversion and exchange rate lookups using real ECB reference rates, free and without an API key. Supports natural language queries like 'convert 100 USD to EUR' or 'what's the exchange rate between GBP and JPY?'.

A demo MCP server that returns an interactive dashboard (bar chart with dataset selector) as an MCP App via the official MCP Apps extension (SEP-1865).

Gives AI assistants live access to US prescription drug prices by pharmacy with observation dates, the free discount card, and vetted US equivalents of foreign-brand medicines, all through the Model Context Protocol.

Provides AI agents with real-time and historical crypto market data from nine exchanges, including order book metrics, volumes, spreads, and market microstructure via the BlackForge API.

Stateless MCP server that wraps OpenAI's Sora, Whisper, GPT-4o Audio, and TTS APIs for generating videos, images, and processing audio.

This MCP server provides comprehensive Google Workspace integration (Gmail, Drive, etc.) with multi-user OAuth. Unique features include RAG-powered natural language to Chat card rendering, runtime Jinja2 macro creation, and dynamic tool management.

Provides real-time cryptocurrency prices, market cap, and 24h change using CoinGecko, with free access and no API key required.

An MCP server that integrates with SerpApi to retrieve search results from multiple search engines including Google, Bing, Yahoo, and others, enabling fast access to both live and archived search data.

An MCP server that lets Claude or ChatGPT read, create, and edit mind maps stored in a GitHub repository, with support for local and HTTP transport.

Merchant-side MCP server for agentbank that lets merchants read their own orders and live Curless wallet balance from an MCP client such as Claude Desktop.

An interactive flashcard MCP App for Claude Desktop. Claude generates flashcards from your request or the conversation and renders them as an inline, gradeable flip-card review with spaced repetition.