{"version":"2.1.212","anchor":"mcp-websocket-subprotocol-support","canonical_anchor":"mcp-websocket-subprotocol-support","heading":"MCP WebSocket Subprotocol Support","tier":null,"area":null,"scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.212\/e\/mcp-websocket-subprotocol-support","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.212","markdown":"### MCP WebSocket Subprotocol Support\n\nMCP WebSocket connection errors now include the list of subprotocols offered by the server when relevant. The message format is `(subprotocols: \"proto1\", \"proto2\")` appended to connection error text.\n\n**Evidence**\n\n\"(subprotocols:\" (search for `\"Nxu\"`)"}