MCP 2026-07-28 deleted the initialize handshake, sessions, and server-initiated requests. Here's every error you'll see, what it means, and what to do about it.
I updated my editor last week and three MCP servers stopped working. Same error each time:
{"jsonrpc":"2.0","id":1,"error":{"code":-32601,"message":"Method not found: initialize"}}
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I spent about forty minutes assuming I'd broken something. I hadn't. Neither had the server authors. The spec changed underneath all of us.
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