Handshake (MCP Handshake)

The Handshake is the initial negotiation phase when an MCP client first connects to a server. It ensures that both parties are compatible and agree on how to communicate.

Handshake Steps

  1. Initialize Request: Client sends a list of its capabilities and protocol version.
  2. Initialize Response: Server returns its capabilities and confirms the protocol version.
  3. Initialized Notification: Client confirms it's ready to start multi-turn communication.

Until the handshake is complete, no tool calls or resource reads can be performed.

Questions & Answers

What is the primary purpose of the MCP Handshake?

The handshake is the initial negotiation phase where the client and server confirm compatibility, exchange capabilities, and agree on the protocol version to ensure a stable communication link.

What are the three main steps in an MCP handshake?

The steps are: 1. Initialize Request (client sends capabilities), 2. Initialize Response (server returns capabilities), and 3. Initialized Notification (client confirms it's ready).

Can an AI model use a tool before the handshake is finished?

No, until the handshake is complete and the Initialized Notification has been sent, no tool calls or resource reads can be performed.

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