Ping

The Model Context Protocol includes an optional ping mechanism that allows either party to verify that their counterpart is still responsive and the connection is alive.

Overview

The ping functionality is implemented through a simple request/response pattern. Either the client or server can initiate a ping by sending a ping request.

Message Format

A ping request is a standard JSON-RPC request with no parameters:

{
  "jsonrpc": "2.0",
  "id": "123",
  "method": "ping"
}

Behavior Requirements

1. The receiver MUST respond promptly with an empty response:

{
  "jsonrpc": "2.0",
  "id": "123",
  "result": {}
}

2. If no response is received within a reasonable timeout period, the sender MAY:
   • Consider the connection stale
   • Terminate the connection
   • Attempt reconnection procedures

Usage Patterns

sequenceDiagram
    participant Sender
    participant Receiver

    Sender->>Receiver: ping request
    Receiver->>Sender: empty response

Implementation Considerations

• Implementations SHOULD periodically issue pings to detect connection health
• The frequency of pings SHOULD be configurable
• Timeouts SHOULD be appropriate for the network environment
• Excessive pinging SHOULD be avoided to reduce network overhead

Error Handling

• Timeouts SHOULD be treated as connection failures
• Multiple failed pings MAY trigger connection reset
• Implementations SHOULD log ping failures for diagnostics