building-mcp-server-on-cloudflare
Builds remote MCP (Model Context Protocol) servers on Cloudflare Workers with tools, OAuth authentication, and production deployment. Generates server code, configures auth providers, and deploys to Workers. Use when: user wants to "build MCP server", "create MCP tools", "remote MCP", "deploy MCP", add "OAuth to MCP", or mentions Model Context Protocol on Cloudflare. Also triggers on "MCP authentication" or "MCP deployment".
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/cloudflare/cloudflare-docs --skill building-mcp-server-on-cloudflare- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads building-mcp-server-on-cloudflare automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
Building MCP Servers on Cloudflare
Creates production-ready Model Context Protocol servers on Cloudflare Workers with tools, authentication, and deployment.
When to Use
- User wants to build a remote MCP server
- User needs to expose tools via MCP
- User asks about MCP authentication or OAuth
- User wants to deploy MCP to Cloudflare Workers
Prerequisites
- Cloudflare account with Workers enabled
- Node.js 18+ and npm/pnpm/yarn
- Wrangler CLI (
npm install -g wrangler)
Quick Start
Option 1: Public Server (No Auth)
npm create cloudflare@latest -- my-mcp-server \
--template=cloudflare/ai/demos/remote-mcp-authless
cd my-mcp-server
npm start
Server runs at http://localhost:8788/mcp
Option 2: Authenticated Server (OAuth)
npm create cloudflare@latest -- my-mcp-server \
--template=cloudflare/ai/demos/remote-mcp-github-oauth
cd my-mcp-server
Requires OAuth app setup. See references/oauth-setup.md.
Core Workflow
Step 1: Define Tools
Tools are functions MCP clients can call. Define them using server.tool():
import { McpAgent } from "agents/mcp";
import { z } from "zod";
export class MyMCP extends McpAgent {
server = new Server({ name: "my-mcp", version: "1.0.0" });
async init() {
// Simple tool with parameters
this.server.tool(
"add",
{ a: z.number(), b: z.number() },
async ({ a, b }) => ({
content: [{ type: "text", text: String(a + b) }],
})
);
// Tool that calls external API
this.server.tool(
"get_weather",
{ city: z.string() },
async ({ city }) => {
const response = await fetch(`https://api.weather.com/${city}`);
const data = await response.json();
return {
content: [{ type: "text", text: JSON.stringify(data) }],
};
}
);
}
}
Step 2: Configure Entry Point
Public server (src/index.ts):
import { MyMCP } from "./mcp";
export default {
fetch(request: Request, env: Env, ctx: ExecutionContext) {
const url = new URL(request.url);
if (url.pathname === "/mcp") {
return MyMCP.serveSSE("/mcp").fetch(request, env, ctx);
}
return new Response("MCP Server", { status: 200 });
},
};
export { MyMCP };
Authenticated server — See references/oauth-setup.md.
Step 3: Test Locally
# Start server
npm start
# In another terminal, test with MCP Inspector
npx @modelcontextprotocol/inspector@latest
# Open http://localhost:5173, enter http://localhost:8788/mcp
Step 4: Deploy
npx wrangler deploy
Server accessible at https://[worker-name].[account].workers.dev/mcp
Step 5: Connect Clients
Claude Desktop (claude_desktop_config.json):
{
"mcpServers": {
"my-server": {
"command": "npx",
"args": ["mcp-remote", "https://my-mcp.workers.dev/mcp"]
}
}
}
Restart Claude Desktop after updating config.
Tool Patterns
Return Types
// Text response
return { content: [{ type: "text", text: "result" }] };
// Multiple content items
return {
content: [
{ type: "text", text: "Here's the data:" },
{ type: "text", text: JSON.stringify(data, null, 2) },
],
};
Input Validation with Zod
this.server.tool(
"create_user",
{
email: z.string().email(),
name: z.string().min(1).max(100),
role: z.enum(["admin", "user", "guest"]),
age: z.number().int().min(0).optional(),
},
async (params) => {
// params are fully typed and validated
}
);
Accessing Environment/Bindings
export class MyMCP extends McpAgent<Env> {
async init() {
this.server.tool("query_db", { sql: z.string() }, async ({ sql }) => {
// Access D1 binding
const result = await this.env.DB.prepare(sql).all();
return { content: [{ type: "text", text: JSON.stringify(result) }] };
});
}
}
Authentication
For OAuth-protected servers, see references/oauth-setup.md.
Supported providers:
- GitHub
- Auth0
- Stytch
- WorkOS
- Any OAuth 2.0 compliant provider
Wrangler Configuration
Minimal wrangler.toml:
name = "my-mcp-server"
main = "src/index.ts"
compatibility_date = "2024-12-01"
[durable_objects]
bindings = [{ name = "MCP", class_name = "MyMCP" }]
[[migrations]]
tag = "v1"
new_classes = ["MyMCP"]
With bindings (D1, KV, etc.):
[[d1_databases]]
binding = "DB"
database_name = "my-db"
database_id = "xxx"
[[kv_namespaces]]
binding = "KV"
id = "xxx"
Common Issues
"Tool not found" in Client
- Verify tool name matches exactly (case-sensitive)
- Ensure
init()registers tools before connections - Check server logs:
wrangler tail
Connection Fails
- Confirm endpoint path is
/mcp - Check CORS if browser-based client
- Verify Worker is deployed:
wrangler deployments list
OAuth Redirect Errors
- Callback URL must match OAuth app config exactly
- Check
GITHUB_CLIENT_IDandGITHUB_CLIENT_SECRETare set - For local dev, use
http://localhost:8788/callback
References
- references/examples.md — Official templates and production examples
- references/oauth-setup.md — OAuth provider configuration
- references/tool-patterns.md — Advanced tool examples
- references/troubleshooting.md — Error codes and fixes
FAQ
What does the building-mcp-server-on-cloudflare skill do?
Builds remote MCP (Model Context Protocol) servers on Cloudflare Workers with tools, OAuth authentication, and production deployment. Generates server code, configures auth providers, and deploys to Workers. Use when: user wants to "build MCP server", "create MCP tools", "remote MCP", "deploy MCP", add "OAuth to MCP", or mentions Model Context Protocol on Cloudflare. Also triggers on "MCP authentication" or "MCP deployment".
How do I install building-mcp-server-on-cloudflare?
Run npx skills add https://github.com/cloudflare/cloudflare-docs --skill building-mcp-server-on-cloudflare in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/building-mcp-server-on-cloudflare/ (personal) or .claude/skills/building-mcp-server-on-cloudflare/ (project).
Which AI agents can use building-mcp-server-on-cloudflare?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is building-mcp-server-on-cloudflare safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains building-mcp-server-on-cloudflare?
It is published by cloudflare in cloudflare/cloudflare-docs, and it is an official skill from the maker of the technology it covers. It has 44 recorded installs.
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