fix: v2 follow-up improvements (modelcontextprotocol#1318)

Author: felixweinberger

CONTRIBUTING.md

@@ -2,20 +2,40 @@
 
 We welcome contributions to the Model Context Protocol TypeScript SDK! This document outlines the process for contributing to the project.
 
+## Branches
+
+This repository has two main branches:
+
+- **`main`** – v2 of the SDK (currently in development). This is a monorepo with split packages.
+- **`v1.x`** – stable v1 release. Bug fixes and patches for v1 should target this branch.
+
+**Which branch should I use as a base?**
+
+- For **new features** or **v2-related work**: base your PR on `main`
+- For **v1 bug fixes** or **patches**: base your PR on `v1.x`
+
 ## Getting Started
 
+This project uses [pnpm](https://pnpm.io/) as its package manager. If you don't have pnpm installed, enable it via [corepack](https://nodejs.org/api/corepack.html) (included with Node.js 16.9+):
+
+```bash
+corepack enable
+```
+
+Then:
+
 1. Fork the repository
 2. Clone your fork: `git clone https://github.com/YOUR-USERNAME/typescript-sdk.git`
-3. Install dependencies: `npm install`
-4. Build the project: `npm run build`
-5. Run tests: `npm test`
+3. Install dependencies: `pnpm install`
+4. Build the project: `pnpm build:all`
+5. Run tests: `pnpm test:all`
 
 ## Development Process
 
-1. Create a new branch for your changes
+1. Create a new branch for your changes (based on `main` or `v1.x` as appropriate)
 2. Make your changes
-3. Run `npm run lint` to ensure code style compliance
-4. Run `npm test` to verify all tests pass
+3. Run `pnpm lint:all` to ensure code style compliance
+4. Run `pnpm test:all` to verify all tests pass
 5. Submit a pull request
 
 ## Pull Request Guidelines
@@ -28,8 +48,17 @@ We welcome contributions to the Model Context Protocol TypeScript SDK! This docu
 
 ## Running Examples
 
-- Start the server: `npm run server`
-- Run the client: `npm run client`
+See [`examples/server/README.md`](examples/server/README.md) and [`examples/client/README.md`](examples/client/README.md) for a full list of runnable examples.
+
+Quick start:
+
+```bash
+# Run a server example
+pnpm --filter @modelcontextprotocol/examples-server exec tsx src/simpleStreamableHttp.ts
+
+# Run a client example (in another terminal)
+pnpm --filter @modelcontextprotocol/examples-client exec tsx src/simpleStreamableHttp.ts
+```
 
 ## Code of Conduct
 

README.md

@@ -1,6 +1,13 @@
 # MCP TypeScript SDK
 
-![NPM Version](https://img.shields.io/npm/v/%40modelcontextprotocol%server) ![NPM Version](https://img.shields.io/npm/v/%40modelcontextprotocol%client) ![MIT licensed](https://img.shields.io/npm/l/%40modelcontextprotocol%server)
+> [!IMPORTANT]
+> **This is the `main` branch which contains v2 of the SDK (currently in development, pre-alpha).**
+>
+> We anticipate a stable v2 release in Q1 2026. Until then, **v1.x remains the recommended version** for production use. v1.x will continue to receive bug fixes and security updates for at least 6 months after v2 ships to give people time to upgrade.
+>
+> For v1 documentation and code, see the [`v1.x` branch](https://github.com/modelcontextprotocol/typescript-sdk/tree/v1.x).
+
+![NPM Version](https://img.shields.io/npm/v/%40modelcontextprotocol%2Fserver) ![NPM Version](https://img.shields.io/npm/v/%40modelcontextprotocol%2Fclient) ![MIT licensed](https://img.shields.io/npm/l/%40modelcontextprotocol%2Fserver)
 
 <details>
 <summary>Table of Contents</summary>

packages/server/src/index.ts

@@ -1,6 +1,5 @@
 export * from './server/completable.js';
 export * from './server/express.js';
-export * from './server/inMemoryEventStore.js';
 export * from './server/mcp.js';
 export * from './server/server.js';
 export * from './server/sse.js';

packages/server/src/server/inMemoryEventStore.ts

@@ -4,14 +4,48 @@ import { createServer, type Server } from 'node:http';
 import { Client, StreamableHTTPClientTransport } from '@modelcontextprotocol/client';
 import {
     CallToolResultSchema,
-    InMemoryEventStore,
     LoggingMessageNotificationSchema,
     McpServer,
     StreamableHTTPServerTransport
 } from '@modelcontextprotocol/server';
+import type { EventStore, JSONRPCMessage } from '@modelcontextprotocol/server';
 import type { ZodMatrixEntry } from '@modelcontextprotocol/test-helpers';
 import { listenOnRandomPort, zodTestMatrix } from '@modelcontextprotocol/test-helpers';
 
+/**
+ * Simple in-memory EventStore for testing resumability.
+ */
+class InMemoryEventStore implements EventStore {
+    private events = new Map<string, { streamId: string; message: JSONRPCMessage }>();
+
+    async storeEvent(streamId: string, message: JSONRPCMessage): Promise<string> {
+        const eventId = `${streamId}_${Date.now()}_${Math.random().toString(36).slice(2, 10)}`;
+        this.events.set(eventId, { streamId, message });
+        return eventId;
+    }
+
+    async replayEventsAfter(
+        lastEventId: string,
+        { send }: { send: (eventId: string, message: JSONRPCMessage) => Promise<void> }
+    ): Promise<string> {
+        if (!lastEventId || !this.events.has(lastEventId)) return '';
+        const streamId = lastEventId.split('_')[0] ?? '';
+        if (!streamId) return '';
+
+        let found = false;
+        const sorted = [...this.events.entries()].sort((a, b) => a[0].localeCompare(b[0]));
+        for (const [eventId, { streamId: sid, message }] of sorted) {
+            if (sid !== streamId) continue;
+            if (eventId === lastEventId) {
+                found = true;
+                continue;
+            }
+            if (found) await send(eventId, message);
+        }
+        return streamId;
+    }
+}
+
 describe.each(zodTestMatrix)('$zodVersionLabel', (entry: ZodMatrixEntry) => {
     const { z } = entry;
     describe('Transport resumability', () => {