Add HTTP client connect for initialize handshake#327
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atesgoral wants to merge 2 commits intomodelcontextprotocol:mainfrom
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Add HTTP client connect for initialize handshake#327atesgoral wants to merge 2 commits intomodelcontextprotocol:mainfrom
atesgoral wants to merge 2 commits intomodelcontextprotocol:mainfrom
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Per MCP spec, clients that no longer need a session SHOULD send an HTTP DELETE to the MCP endpoint with the Mcp-Session-Id header to explicitly terminate it. Servers MAY respond with 405 Method Not Allowed when they don't support client-initiated termination. `MCP::Client::HTTP#close` sends the DELETE with session headers, clears local session state regardless of outcome, and is a no-op when no session has been established. https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#session-management
Per MCP spec, clients must send an `initialize` request followed by a `notifications/initialized` notification before issuing any other requests. The server's `InitializeResult` (protocol version, server capabilities, server info, instructions) negotiates the session for the lifetime of the connection. `MCP::Client::HTTP#connect` performs the full handshake, caches the server's `InitializeResult`, and exposes it via the `server_info` reader. `connected?` reports handshake completion. `connect` is idempotent — a second call returns the cached result without contacting the server. After `close`, state is cleared and `connect` will handshake again. https://modelcontextprotocol.io/specification/2025-11-25/basic/lifecycle#initialization
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Summary
Adds
MCP::Client::HTTP#connectto perform the MCP initialization handshake: sends theinitializerequest, followed by the requirednotifications/initializednotification, and caches the server'sInitializeResult(protocol version, capabilities, server info, instructions).connect(client_info:, protocol_version:, capabilities:)— idempotent; a second call returns the cached result without contacting the server. Afterclose, state is cleared andconnectwill handshake again.connected?— predicate set only after the full handshake completes (not mid-handshake), so a failed notification send leaves the transport in a consistent state.server_info— reader exposing the cachedInitializeResult.Replaces the previous pattern where callers had to construct the
initializerequest manually:Stacked on #326 — the diff here includes #326's commits; please merge #326 first, then this will show only the handshake commit.
Test plan
client_info/protocol_version/capabilities, idempotence, JSON-RPC error response, missingresult,connected?lifecycle throughclose, reconnect aftercloserake test— 775 runs, 1927 assertions, 0 failuresrubocopclean on touched filesexamples/streamable_http_server.rb: connect → tools → close → reconnect