posthog-v7.75.9

Patch changes

• 8cd8eb5 MCP analytics now sends one $mcp_initialize for each initialize request that a client sends.

  Before, the SDK sent the event on the first request of each session, once per process. A stateless fleet sent one event for each pod that a session reached. A conversation-anchored session sent another event. A client that connected and sent no other request sent no event.

  On MCP SDK 2.x, the event comes from Server.middleware on every transport. Requests on the 2026-07-28 spec, which has no initialize, no longer send one. On MCP SDK 1.x over HTTP, the event comes from PostHogMcpStatelessSessionMiddleware. The apps that instrument() autowires get this with no change. If you mount the middleware by hand, pass the server as server=. MCP SDK 1.x over stdio keeps the first request as the trigger.

  The event now also has the handshake request as $mcp_parameters. On MCP SDK 2.x, it also has the server reply as $mcp_response. — Thanks @gesh!

• 48889b6 The Claude Agent SDK integration now takes the cumulative input and cache token counts from the final message_delta usage, which grow past the message_start values when server tools such as web search run, and sets $ai_web_search_count from server_tool_use.web_search_requests. Streamed generations used to under-report input tokens and cache writes and never recorded the web search count. — Thanks @pcbeingused333!