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ruby-sdk/docs/_server/ping.md
Koichi ITO c9d36b04bf [Doc] Align the Docs Page Names With the MCP Specification 
Three pages carried names the 2026-07-28 specification does not use: "Multi-Round-Trip Results" for
the pattern the specification titles Multi Round-Trip Requests (MRTR) and serves at basic/patterns/mrtr -
the results are the `InputRequiredResult` wire type, not the feature - plus "Completions" for the utility
the specification titles Completion, and "Notification Subscriptions" for the pattern it titles Subscriptions.
Retitle the three pages to the specification's names, move them to /server/mrtr/ and /client/mrtr/,
/server/completion/, and /server/subscriptions/ following the specification's slugs, update every internal reference,
and keep the URLs published with v1.3.0 working via jekyll-redirect-from.
The Discovery page keeps its title but moves from /server/discovery/ to /server/discover/, matching
the specification's slug and the `server/discover` RPC, with its published URL redirected the same way.
2026-08-22 18:07:38 +09:00

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default Ping 15

Ping

The MCP Ruby SDK supports the MCP ping utility, which allows either side of the connection to verify that the peer is still responsive. A ping request has no parameters, and the receiver MUST respond promptly with an empty result.

{: .note }

ping belongs to the handshake lifecycle: MCP 2026-07-28 removes the method altogether (SEP-2575), since requests of the modern lifecycle are single POST exchanges whose connection itself signals liveness, leaving nothing to probe between requests. The server answers ping on the handshake lifecycle only - a modern request naming it is rejected with -32601 Method not found - and calling ping on a server_context while serving a modern request raises an error. The long-lived subscriptions/listen stream is kept alive by SSE keepalive frames instead.

Servers respond to incoming ping requests automatically - no setup is required. Any MCP::Server instance replies with an empty result.

Servers can also send ping requests to the client via ServerSession#ping. ping is exempt from the SEP-2260 association requirement, so it may also be sent outside a handler. Inside a tool handler that receives server_context:, call ping on it:

class HealthCheckTool < MCP::Tool
  description "Verifies the client is still responsive"

  def self.call(server_context:)
    server_context.ping # => {} on success

    MCP::Tool::Response.new([{ type: "text", text: "client is alive" }])
  end
end

#ping raises MCP::Server::ValidationError when the client returns a result that is not a Hash. Transport-level errors (e.g., the client returning a JSON-RPC error) propagate as exceptions raised by the transport layer.

Server-to-client requests are bounded by a timeout on the Streamable HTTP transport; see Timeouts.

Client Side

Pinging the server with MCP::Client#ping is documented on the client Ping page.