MCP Server

What is MCP?

The Model Context Protocol (MCP) is an open standard for connecting AI models to external tools and data sources. FlowMCP can run as an MCP server, exposing all active schemas as tools to any MCP-compatible AI client. Instead of writing custom server code for each API, you declare schemas and FlowMCP handles the MCP protocol, parameter validation, and API execution.

Architecture

How FlowMCP bridges AI clients and APIs: The AI client sends tool calls over the MCP protocol. FlowMCP resolves the correct schema, validates parameters, calls the upstream API, and returns the result.

Starting the Server

The fastest way to serve schemas is through the CLI:

# Serve all active tools as MCP server (stdio)
flowmcp server

# Serve with specific schema directory
flowmcp server --schemas ./schemas/

# Serve a specific group
flowmcp server --group crypto

For programmatic control, see the Server Integration guide.

Client Integration

Claude Desktop
Cursor
Claude Code

Add FlowMCP to your claude_desktop_config.json:

{
  "mcpServers": {
    "flowmcp": {
      "command": "npx",
      "args": ["-y", "flowmcp", "server"],
      "env": {
        "ETHERSCAN_API_KEY": "your_key_here",
        "MORALIS_API_KEY": "your_key_here"
      }
    }
  }
}

Config file location:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

After editing the config, restart Claude Desktop to pick up the new MCP server configuration.

Add FlowMCP to your Cursor MCP settings:

{
  "mcpServers": {
    "flowmcp": {
      "command": "npx",
      "args": ["-y", "flowmcp", "server"]
    }
  }
}

Open Cursor Settings and navigate to the MCP section to add this configuration.

Add FlowMCP as a local MCP server:

claude mcp add flowmcp --scope local -- npx -y flowmcp server

Claude Code will automatically start the server when needed.

Environment Variables

API keys required by your schemas can be provided in three ways:

Method	Example	Best For
`~/.flowmcp/.env` file	`ETHERSCAN_API_KEY=abc123`	Persistent local setup
`env` block in client config	See Claude Desktop example above	Per-client configuration
System environment variables	`export ETHERSCAN_API_KEY=abc123`	CI/CD and containers

API keys are injected as server parameters at runtime and are never exposed to the AI client. They are only used when FlowMCP calls the upstream API on behalf of the AI.

What Gets Exposed

All active tools from your .flowmcp/config.json become MCP primitives:

Schema Primitive	MCP Primitive	Description
Tools	MCP Tools	API endpoints the AI can call
Resources	MCP Resources	Static data the AI can read
Prompts	MCP Prompts	Pre-built prompt templates

Each tool is registered with its name, description, and a Zod-validated parameter schema — giving the AI client everything it needs to discover and call the tool correctly.

Getting Started

Schemas

Agents

Usage

What is MCP?

Architecture

Starting the Server

Client Integration

Environment Variables

What Gets Exposed

What’s Next

Server Integration

Schema Library

Getting Started

Schemas

Agents

Usage

​What is MCP?

​Architecture

​Starting the Server

​Client Integration

​Environment Variables

​What Gets Exposed

​What’s Next

Server Integration

Schema Library

What is MCP?

Architecture

Starting the Server

Client Integration

Environment Variables

What Gets Exposed

What’s Next