mcp-ts-template

Build production-grade Model Context Protocol (MCP) servers with a powerful, type-safe, and extensible foundation.

This template provides a comprehensive foundation for building rich Model Context Protocol servers, adhering to the MCP 2025-06-18 specification and modern best practices. It includes a fully-featured server, production-ready utilities, and clear documentation to get you up and running quickly.

🤔 What Can You Build With This?

Developing a reliable server for AI agents requires a thoughtful approach to architecture, error handling, and security. This template provides a starting point to help you:

• Focus on Innovation: Move past the setup and boilerplate. Spend your time building the unique logic for your tools.
• Build with Confidence: Start with a foundation that includes logging, error handling, security features, and a testing framework.
• Write Maintainable Code: The modular architecture is designed to be easy to understand, maintain, and extend as your project grows.
• Create for AI: With detailed schemas and developer resources (like .clinerules), the template is set up for building tools that LLM agents can easily understand and use.

Note on src/mcp-client & src/agent: The MCP client & Agent components have been enhanced and moved to the (coming soon)atlas-mcp-agent repository. This template now focuses exclusively on providing a best-in-class server implementation and framework.

✨ Key Features

Feature Area	Description	Key Components / Location
🔌 MCP Server	A functional server with example tools and resources. Supports stdio and a Streamable HTTP transport built with Hono.	src/mcp-server/, src/mcp-server/transports/
🔭 Observability	Built-in OpenTelemetry for distributed tracing and metrics. Auto-instrumentation for core modules and custom tracing for all tool executions.	src/utils/telemetry/
🚀 Production Utilities	Logging, Error Handling, ID Generation, Rate Limiting, Request Context tracking, Input Sanitization.	src/utils/
🔒 Type Safety/Security	Strong type checking via TypeScript & Zod validation. Built-in security utilities (sanitization, auth middleware for HTTP).	Throughout, src/utils/security/, src/mcp-server/transports/auth/
⚙️ Error Handling	Consistent error categorization (JsonRpcErrorCode), detailed logging, centralized handling (ErrorHandler).	src/utils/internal/errorHandler.ts, src/types-global/
📚 Documentation	Comprehensive README.md, structured JSDoc comments, API references.	README.md, Codebase, tsdoc.json, docs/api-references/
🕵️ Interaction Logging	Captures raw requests and responses for all external LLM provider interactions to a dedicated interactions.log file for full traceability.	src/utils/internal/logger.ts
🤖 Agent Ready	Includes a .clinerules developer cheatsheet tailored for LLM coding agents.	.clinerules/
🛠️ Utility Scripts	Scripts for cleaning builds, setting executable permissions, generating directory trees, and fetching OpenAPI specs.	scripts/
💾 Storage Service	A flexible, provider-based storage layer for persisting data. Supports in-memory, filesystem, and Supabase backends out-of-the-box.	src/storage/
🧩 Services	Reusable modules for LLM (OpenRouter) integration.	src/services/
🧪 Integration Testing	Integrated with Vitest for fast and reliable integration testing. Includes example tests for core logic and a coverage reporter.	vitest.config.ts, tests/
⏱️ Performance Metrics	Built-in utility to automatically measure and log the execution time and payload size of every tool call.	src/utils/internal/performance.ts

Architecture Overview

This template is built on a set of architectural principles to ensure modularity, testability, and operational clarity.

• Core Server (src/mcp-server/server.ts): The central point where tools and resources are registered, using the McpServer class directly from the SDK.
• Transports (src/mcp-server/transports/): The transport layer connects the core server to the outside world. It supports both stdio for direct process communication and a streamable Hono-based http server.
• "Logic Throws, Handler Catches": This is the immutable cornerstone of our error-handling strategy.
  • Core Logic (logic.ts): This layer is responsible for pure, self-contained business logic. It throws a structured McpError on any failure.
  • Handlers (registration.ts): This layer interfaces with the server, invokes the core logic, and catches any errors. It is the exclusive location where errors are processed and formatted into a final response.
• Structured, Traceable Operations: Every operation is traced from initiation to completion via a RequestContext that is passed through the entire call stack, ensuring comprehensive and structured logging.

Quick Start

1. Installation

Clone the repository and install dependencies:

git clone https://github.com/cyanheads/mcp-ts-template.git
cd mcp-ts-template
npm install

2. Build the Project

npm run build
# Or use 'npm run rebuild' for a clean install

3. Running the Server

• Via Stdio (Default):

  npm run start:server

• Via Streamable HTTP:

  npm run start:server:http

4. Running Tests

This template uses Vitest for testing, with a strong emphasis on integration testing to ensure all components work together correctly.

• Run all tests once:

  npm test

• Run tests in watch mode:

  npm run test:watch

• Run tests and generate a coverage report:

  npm run test:coverage

⚙️ Configuration

Configure the server using these environment variables (or a .env file):

Variable	Description	Default
MCP_TRANSPORT_TYPE	Server transport: stdio or http.	stdio
MCP_SESSION_MODE	Session mode for HTTP: stateless, stateful, or auto.	auto
MCP_HTTP_PORT	Port for the HTTP server.	3010
MCP_HTTP_HOST	Host address for the HTTP server.	127.0.0.1
MCP_ALLOWED_ORIGINS	Comma-separated allowed origins for CORS.	(none)
MCP_AUTH_MODE	Authentication mode for HTTP: jwt, oauth, or none.	none
MCP_AUTH_SECRET_KEY	Required for jwt mode. Secret key (min 32 chars) for signing/verifying auth tokens.	(none - MUST be set in production)
OAUTH_ISSUER_URL	Required for oauth mode. The issuer URL of your authorization server.	(none)
OAUTH_AUDIENCE	Required for oauth mode. The audience identifier for this MCP server.	(none)
STORAGE_PROVIDER_TYPE	The storage backend to use: in-memory, filesystem, or supabase.	filesystem
STORAGE_FILESYSTEM_PATH	Required for filesystem mode. The local path for storing data.	./.storage
SUPABASE_URL	Required for supabase mode. The URL of your Supabase project.	(none)
SUPABASE_SERVICE_ROLE_KEY	Required for supabase mode. The service role key for your Supabase project.	(none)
OPENROUTER_API_KEY	API key for OpenRouter.ai service.	(none)
OTEL_ENABLED	Set to true to enable OpenTelemetry instrumentation.	false
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT	The OTLP endpoint for exporting traces (e.g., http://localhost:4318/v1/traces).	(none; logs to file)
OTEL_EXPORTER_OTLP_METRICS_ENDPOINT	The OTLP endpoint for exporting metrics (e.g., http://localhost:4318/v1/metrics).	(none)

🏗️ Project Structure

• src/mcp-server/: Contains the core MCP server, tools, resources, and transport handlers.
• src/config/: Handles loading and validation of environment variables.
• src/services/: Reusable modules for integrating with external services (OpenRouter).
• src/types-global/: Defines shared TypeScript interfaces and type definitions.
• src/utils/: Core utilities (logging, error handling, security, etc.).
• src/index.ts: The main entry point that initializes and starts the server.

Explore the full structure yourself:

See the current file tree in docs/tree.md or generate it dynamically:

npm run tree

🧩 Extending the System

The template enforces a strict, modular pattern for adding new tools and resources, as mandated by the Architectural Standard. The echoTool (src/mcp-server/tools/echoTool/) serves as the canonical example.

The "Logic Throws, Handler Catches" Pattern

This is the cornerstone of the architecture:

1. logic.ts: This file contains the pure business logic.

   • It defines the Zod schemas for input and output, which serve as the single source of truth for the tool's data contract.
   • The core logic function is pure: it takes validated parameters and a request context, and either returns a result or throws a structured McpError.
   • It never contains try...catch blocks for formatting a final response.

2. registration.ts: This file is the "handler" that connects the logic to the MCP server.

   • It imports the schemas and logic function from logic.ts.
   • It calls server.registerTool(), providing the tool's metadata and the runtime handler.
   • The runtime handler always wraps the call to the logic function in a try...catch block. This is the only place where errors are caught, processed by the ErrorHandler, and formatted into a standardized error response.

This pattern ensures that core logic remains decoupled, pure, and easily testable, while the registration layer handles all transport-level concerns, side effects, and response formatting.

🌍 Explore More MCP Resources

Looking for more examples, guides, and pre-built MCP servers? Check out the companion repository:

➡️ cyanheads/model-context-protocol-resources

📜 License

This project is licensed under the Apache License 2.0. See the LICENSE file for details.