mcploader 0.1.0

This package is a small helper module that lets you define and consume multiple MCP servers (stdio, SSE, or Streamable HTTP) from a JSON configuration. It uses `pydantic-ai` MCP clients and validates configuration with Pydantic models.

MCPLoader

MCPLoader is a small helper module that lets you define and consume multiple MCP servers (stdio, SSE, or Streamable HTTP) from a JSON configuration. It uses pydantic-ai MCP clients and validates configuration with Pydantic models.

Features

• HTTP (SSE / Streamable HTTP) and STDIO server types
• Configuration validation with Pydantic
• Multiple MCP servers from a single JSON file
• Simple Python API: pass a config path, get ready-to-use server clients

Installation

Use it as a module inside your own codebase. Required dependencies:

pip install mcploader

or

uv add mcploader

Quick start

from mcploader import MCPServerManager

# Provide your configuration file path (e.g., config/http.json or data/mcp/http.json)
manager = MCPServerManager("config/http.json")

servers = manager.servers # serialized list of MCPServer

from pydantic_ai import Agent

agent = Agent('openai:gpt-4o', toolsets=servers)

async def main():
    async with agent:
        await agent.run('Ask something here...')

import asyncio

if __name__ == '__main__':
    asyncio.run(main())

Configuration

Configuration is a JSON object with a root key mcpServers. Each key under mcpServers is a server name; the value is its configuration.

General schema

{
  "mcpServers": {
    "<serverName>": { ... }
  }
}

Each server can be one of two forms:

• STDIO: StdioServerParameters
• HTTP: ServerParameters (contains a transport body)

HTTP (SSE / Streamable HTTP) example

{
  "mcpServers": {
    "server1": {
      "transport": {
        "type": "streamable-http", // or "sse"
        "url": "http://127.0.0.1:8000/mcp",
        "headers": {
          "Authorization": "Bearer your-token-here",
          "Content-Type": "application/json",
          "User-Agent": "Claude-Desktop/1.0",
          "X-API-Version": "v1"
        },
        "timeout": 30000,
        "readTimeout": 300000,
        "maxRetries": 5
      }
    }
  }
}

type is normalized to lowercase and must be one of:

• sse
• streamable-http

STDIO example

{
  "mcpServers": {
    "server1": {
      "command": "deno",
      "args": ["run", "-N", "-R=node_modules", "-W=node_modules", "--node-modules-dir=auto", "jsr:@pydantic/mcp-run-python", "stdio"],
      "env": { "OPENAI_API_KEY": "..." },
      "cwd": "/usr/path/to",
      "timeout": 10,
      "readTimeout": 300,
      "maxRetries": 3
    }
  }
}

Fields and types (summary)

• HTTP (ServerParameters.transport: ServerBody)
  • type: "sse" | "streamable-http"
  • url: a valid URL
  • headers: dict[str, str] (optional)
  • timeout: request timeout in ms (default 30000)
  • readTimeout: read timeout in ms (default 300000)
  • maxRetries: retry count (default 5)
• STDIO (StdioServerParameters)
  • command: command to execute (e.g., deno, python)
  • args: command arguments (list)
  • env: environment variables (key/value)
  • cwd: working directory (optional)
  • timeout: timeout in seconds (default 30)
  • readTimeout: read timeout in seconds (default 300)
  • maxRetries: retry count (default 1)

Note: ServerParameters.server_type defaults to "http", StdioServerParameters.server_type defaults to "io". These are used internally to select the proper client.

Folder layout

This repository includes sample configurations under data/.

• data/http.json: Streamable HTTP example

• data/sse.json: SSE example

• data/stdio.json: STDIO example

• Passing paths: Provide the absolute/relative path directly to MCPServerManager, e.g., MCPServerManager("data/mcp/http.json").

• Schema: JSON files under data/ use the same schema; the root must have mcpServers, each key defining a server.

• Environment variants: You can create data/mcp/prod/http.json, data/mcp/dev/http.json, etc., and select the appropriate file at runtime.

API surface

• MCPServerManager(config_path: str): Reads the JSON config and validates it with ServerConfig.
• MCPServerManager.servers -> list[MCPServer]: On first access, creates MCP clients (MCPServerSSE, MCPServerStreamableHTTP, MCPServerStdio) according to the config and caches them.

Feel free to reach me from [e-mail] or my GitHub address.