mcp-server — a TypeScript Model Context Protocol server

An MCP server that gives AI assistants a safe, standard way to use an internal service. It exposes a ticket domain as tools (with Zod-validated inputs) and a resource, served over stdio — plus a demo MCP client that drives it.

ℹ️ An original reference implementation. No proprietary code or data.

What it is

The Model Context Protocol lets AI assistants call tools and read resources through one standard interface. This server puts that boundary in front of an internal "tickets" service: the assistant can list/search/create tickets and change their status, but every argument is validated by a Zod schema before it touches the domain.

flowchart LR
    AI[AI assistant / MCP client] -- stdio --> S[MCP server]
    S --> V[Zod input validation]
    V --> T[Ticket service]
    S -. resource: tickets://all .-> T

Related MCP server: support-triage-agent

Tools

Plus a tickets://all resource exposing the collection as JSON.

Run it

npm install
npm start          # serve over stdio (for an MCP client / AI assistant)
npx tsx src/client.ts   # demo client: launches the server, lists tools, calls one

Point a real assistant at it by configuring an MCP server that runs npx tsx src/index.ts (stdio transport).

Tests

npm run typecheck   # tsc --noEmit
npm test            # vitest

Cover the ticket store (CRUD + search + status), the tool handlers (including the not-found error), and the Zod schemas (accepts valid, rejects bad status / empty fields). The domain and tool logic are framework-free, so they test without spinning up a transport.

Design decisions

• Tools are thin wrappers over plain functions — the service logic is unit-tested directly; the MCP layer only validates and serializes.

• Zod at the boundary — an assistant's arguments are untrusted input; schemas reject malformed calls before they reach internal code.

• stdio transport — the standard local-tool transport; the same server also fits Streamable HTTP without touching the tool definitions.

An original reference implementation. No proprietary code or data is included.