Quickstart: Adapt an existing MCP server for Blaxel

Step-by-step guide to convert an existing stdio-based MCP server to streamable HTTP transport so you can deploy and host it on Blaxel.

MCP (Model Context Protocol) servers provide tools (individual capabilities for accessing specific APIs or databases) that can be used by AI agents. These servers can be hosted on Blaxel’s computing platform and used by AI agents via each server’s global endpoint.

This quickstart walks you through the process of adapting an existing stdio-based MCP server for deployment on Blaxel using the streamable HTTP transport.

Install the Blaxel CLI

Run the installer in a terminal:

macOS and Linux

curl -fsSL https://blaxel.ai/install.sh | sh

The installer checks the Blaxel CLI (bl) against the release checksums, installs it, and adds it to your PATH. On macOS and Linux, it also installs completions for your current shell if you use zsh, bash, or fish. On Windows, configure PowerShell completions separately. It then runs bl setup, which shows what it found and installs it when you press Enter: the Blaxel skills and MCP servers for the coding agents on your machine (Claude Code, Codex, Cursor and others), then the browser login. Run it again at any time to add what is missing.

Install with Homebrew

brew install blaxel-ai/blaxel/blaxel
bl setup

Homebrew 6.0.0+ requires explicit trust for non-official taps, so use the fully qualified formula name.

Installer options

On macOS and Linux, set these variables for sh:

Variable	Effect
VERSION=v0.1.119	Install that release instead of the latest
BINDIR=/usr/local/bin	Install to that folder instead of ~/.local/bin
BL_INSTALL_SETUP=false	Install the CLI only, and run bl setup later
BL_INSTALL_SKILLS=false	Leave your coding agents alone
BL_INSTALL_PATH=false	Do not add bl to your PATH
BL_INSTALL_COMPLETION=false	Skip the shell completions

For example, to install a specific release for all users:

curl -fsSL https://blaxel.ai/install.sh | sudo VERSION=v0.1.119 BINDIR=/usr/local/bin sh

Under sudo, the installer still sets up your own shell, coding agents and login. In CI, it installs the CLI only and leaves the shell configuration and coding agents alone. On Windows, run $env:BL_INSTALL_SETUP = "false" before the installer to install the CLI only.

The installer logs you in. To log in again later, open a terminal and run:

bl login

Get the example project

This quickstart adapts the simple stdio-based MCP weather server from the official Model Context Protocol GitHub repository.

TypeScript

Clone the repository and change to the project working directory:

git clone https://github.com/modelcontextprotocol/quickstart-resources.git
cd quickstart-resources/weather-server-typescript

Python

Clone the repository and change to the project working directory:

git clone https://github.com/modelcontextprotocol/quickstart-resources.git
cd quickstart-resources/weather-server-python

Adapt the server

If your MCP server is already configured to use streamable HTTP, you may skip this step.

Blaxel uses streamable HTTP as the transport layer for MCP servers deployed on its infrastructure. If your MCP server uses stdio (as in this example), you must adapt it to use streamable HTTP instead. The host name and port for the server to bind to are automatically injected by Blaxel during deployment, as HOST and PORT environment variables.

TypeScript

The changes shown below are illustrative only and based on the Blaxel MCP server template for TypeScript.

Add Express to handle HTTP requests and responses:

npm install express
npm install --save-dev @types/express

Here is an example of how you could adapt the existing src/server.ts file for a streamable HTTP server.

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
import { z } from "zod";
import express from 'express';

// ... code ...

const app = express();
app.use(express.json());

app.post('/mcp', async (req, res) => {
  const transport = new StreamableHTTPServerTransport({
    sessionIdGenerator: undefined,
    enableJsonResponse: true,
  });

  res.on('close', () => {
    transport.close();
  });

  await server.connect(transport);
  await transport.handleRequest(req, res, req.body);
});

const port = parseInt(process.env.PORT || '8000');
const host = process.env.HOST || '::';

app.listen(port, host, () => {
  console.log(`MCP Server running on http://${host}:${port}/mcp`);
}).on('error', error => {
  console.error('Server error:', error);
  process.exit(1);
});

Python

The changes shown below are illustrative only and based on the Blaxel MCP server template for Python.

Here is an example of how you could adapt the existing weather.py file for a streamable HTTP server.

from typing import Any
import httpx, os
from mcp.server.fastmcp import FastMCP

# Initialize FastMCP server
mcp = FastMCP(
    "weather",
    stateless_http=True,
    host=os.getenv('HOST', "::"),
    port=os.getenv('PORT', "8000")
)

# ... code ...

def main():
    # Initialize and run the server
    mcp.run(transport='streamable-http')

if __name__ == "__main__":
    main()

Create the deployment configuration

Blaxel looks for a blaxel.toml file to configure the deployment of the MCP server on Blaxel. This file is not mandatory; if the file is not found or a required option is not set, you will be prompted for the information during deployment.

Create a new blaxel.toml file with the following content:

type = "function"

[runtime]
transport = "http-stream"

Blaxel also automatically detects a Dockerfile at the root of the project and uses it to create and deploy a container image of your MCP server. This is a very useful feature that allows you to completely customize the deployment environment for your MCP server, including installing additional system dependencies and using specific versions of libraries or tools.

Create a new Dockerfile with the following content:

TypeScript

FROM node:20-alpine

WORKDIR /app

RUN apk update \
    && apk add build-base curl ca-certificates

COPY . .

RUN npm install

RUN npm run build

EXPOSE 8000

CMD [ "node", "build/index.js" ]

Python

FROM python:3.12-slim

RUN apt-get update && apt-get install -y --no-install-recommends \
    build-essential curl ca-certificates \
  && rm -rf /var/lib/apt/lists/*

RUN curl -LsSf https://astral.sh/uv/install.sh | sh \
  && mv /root/.local/bin/uv /usr/local/bin/uv

WORKDIR /app

COPY . .

RUN uv sync --frozen --no-dev

EXPOSE 8000

CMD ["uv", "run", "weather.py"]

Deploy the MCP server on Blaxel

Deploy the server on Blaxel by running the following command:

bl deploy

Blaxel will handle the build and deployment, producing an HTTPS endpoint on Global Agentics Network. The server endpoint looks like this:

https://run.blaxel.ai/{YOUR-WORKSPACE}/functions/{YOUR-SERVER-NAME}/mcp

You can now connect to this endpoint from any MCP-aware client.