create-mcp-server

A set of development rules for building an MCP server with the @modelcontextprotocol/sdk, a library for exposing tools and other agent-facing features.

In plain words
What is it for?
Use it when implementing an MCP server with resources, prompts, tools, notifications, errors, pagination, and completions.
Why use it?
It defines the required preparation and protocol components so the server can be built consistently over standard input/output or WebSocket connections.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/zackiles/cursor-config/create-mcp-server
Clone the repo
git clone --depth 1 https://github.com/zackiles/cursor-config

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 1,395 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.01395
Opus 5 $0.00000 $0.00698
Sonnet 5 $0.00000 $0.00279
Haiku 4.5 $0.00000 $0.00139

Measured 2d ago against content hash f2da5377fda6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

create-mcp-server scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

.cursor/rules/global/create-mcp-server.mdc · 109 lines

How it starts

The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Context

@modelcontextprotocol/sdk is an SDK for the Model Context Protocol. The full specification of the protocol can be found at https://raw.githubusercontent.com/modelcontextprotocol/specification/refs/heads/main/schema/draft/schema.json

Task

You'll write an MCP server given the available backend Javascript runtime available to you (e.g. Deno, Bun, Node) that supports invoking the server as either a stdio or WebSocket server using the native capabilities of the Javascript runtime available to you. using the native stdio and/or WebSocket available.

Mandatory Reading Before Starting

Understand the dependency @modelcontextprotocol/sdk by reading its README. Understand it's method, types and interfaces, and the two was in which it allows starting a server (the high level, and the lower level for finer control and configuration). Understand the various helper methods it provides. Understand its core components: Resources, Prompts, Tools, Notifications, Errors, Pagination, Completions.

Output

Follow any instructions already given to you and your understanding of the current codebase to generate code that solves the objective while maintaining coherence with the current codebase and any previous instructions. You've been provided an example below that is specific for the Deno runtime simply as an illustration and inspiration for your own design. When you're finished the code, create a task in the local package manager configuration that can run this server locally in a development mode.

Implementing Component Examples

NOTE: If you've been provided no instructions of what the first components should be to implement in the MCP server, than generate a very simple stubbed out example of each: Resource, Prompt, Tool, Notification, Error, Pagination, Completion. Please them in a seperate folder, and have them implemenet an abstract base class that is stubbed out with everything the interfaces and types of @modelcontextprotocol/sdk allows for each.

Read the full file on GitHub · 109 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 109 lines · 0 tokens per session scan A f2da5377fda6

Subscribe to this mod's changes

create-mcp-server is a cursor rule published in the GitHub repository zackiles/cursor-config (17 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,395 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.