Topic 1: Module 2 at a glance, and the setup

By the end of this module, you'll have:

• Driven the notes server by hand over raw stdio and over HTTP with curl, and read every request, response, notification, and error as it crossed the wire.
• Called server/discover, sent the per-request _meta envelope the 2026-07-28 revision requires, and provoked real -32700, -32600, -32601, -32602, -32603, -32020, -32021, and -32022 errors.
• Watched the legacy initialize handshake and Mcp-Session-Id sessions in action, and compared them with the stateless design on the same server.
• Carried state across connections with a tool-returned handle (a start_reading_list tool), and used pagination, progress, cancellation, completions, and resource links.
• Diagnosed a polluted stdout, blocked a DNS rebinding request, and measured latency and bytes on the wire for in-memory, stdio, and HTTP.

Prerequisites: Module 1 (roles, JSON-RPC, primitives, and the tiny search_notes server in examples/m01_first_server.py). Comfortable with curl, HTTP status codes, and async/await.

Where we are: Module 1 connected a client to a one-tool server and let the SDK hide every message. This module takes the cover off. We look at the exact bytes a host and a server exchange, learn the rules that make those bytes a protocol, and see how they travel over the two standard transports.