Claude.ai Connectors moved to a new embedded client that negotiates 2026-07-28 and advertises MCP Apps, but no longer advertises elicitation. source
Claude Code Confirmed on 2026-07-28 by default for HTTP, stdio (v2.1.292+) and claude.ai connectors (v2.1.295+). Opt out with MCP_PROTOCOL_NEGOTIATION=legacy. source
Goose Goose CLI 1.50.0 negotiates 2026-07-28 natively; form elicitation works over remote HTTP. source
ChatGPT Desktop 26.901: form and URL elicitation both verified working over remote HTTP. source
GitHub Copilot CLI 1.0.81 adds the 2026-07-28 protocol; 1.0.83 adds CIMD for OAuth. source
Spec MCP 2026-07-28 released: stateless (no initialize), sampling and roots deprecated. source