MCP compatibility

Protocol version history

Newest protocol versions first, then most recently seen. Repeated client releases and version outcomes are counted together. Protocol acceptance and request outcomes are shown separately; an unsupported method does not reject an accepted version. A counter-offer or discovery response does not prove the client used that version. New observations from token-linked sessions are associated with the exact OAuth identity; older observations without an identity link remain on the global protocol history.

Distinct MCP version observations, newest protocol version first
Client / release	Requested	Protocol version / outcome	Request outcome	Evidence	First / last seen	Count
mcp 0.1.0	2026-07-28	2026-07-28 Version accepted	Request succeeded	Per-request version Identity source clientInfo HTTP version header 2026-07-28 Initialize version Not supplied Metadata version 2026-07-28 Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-11-06 13:30:10 UTC 2026-11-06 13:30:10 UTC	2
mcp 0.1.0	2026-07-28	2026-07-28 Discovery accepted	Request succeeded	server/discover Identity source clientInfo HTTP version header 2026-07-28 Initialize version Not supplied Metadata version 2026-07-28 Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-11-06 13:30:09 UTC 2026-11-06 13:30:09 UTC	1
copilot-cli 1.0.105	2026-07-28	2026-07-28 Version accepted	Request succeeded	Per-request version Identity source clientInfo HTTP version header 2026-07-28 Initialize version Not supplied Metadata version 2026-07-28 Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-29 04:50:10 UTC 2026-10-29 05:36:44 UTC	10
copilot-cli 1.0.105	2026-07-28	2026-07-28 Discovery accepted	Request succeeded	server/discover Identity source clientInfo HTTP version header 2026-07-28 Initialize version Not supplied Metadata version 2026-07-28 Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-29 04:49:09 UTC 2026-10-29 05:35:53 UTC	6
copilot-cli 1.0.102-0.unstable.r40141230562.g130d689	2026-07-28	2026-07-28 Discovery accepted	Request succeeded	server/discover Identity source clientInfo HTTP version header 2026-07-28 Initialize version Not supplied Metadata version 2026-07-28 Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-29 04:37:16 UTC 2026-10-29 05:19:18 UTC	5
copilot-cli 1.0.102-0.unstable.r40141230562.g130d689	2026-07-28	2026-07-28 Version accepted	Request succeeded	Per-request version Identity source clientInfo HTTP version header 2026-07-28 Initialize version Not supplied Metadata version 2026-07-28 Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-29 04:37:16 UTC 2026-10-29 05:18:26 UTC	4
python-httpx2 2.12.0	2025-11-25	2025-11-25 Version accepted	Request succeeded	Per-request version Identity source user-agent HTTP version header 2025-11-25 Initialize version Not supplied Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-11-06 13:25:14 UTC 2026-11-06 13:27:22 UTC	2
mcp 0.1.0	2025-11-25	2025-11-25 Negotiated	Request succeeded	initialize Identity source clientInfo HTTP version header Not supplied Initialize version 2025-11-25 Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-11-06 13:25:14 UTC 2026-11-06 13:27:21 UTC	2
opencode latest/2.2.0/cli	2025-11-25	2025-11-25 Version accepted	Request succeeded	Per-request version Identity source user-agent HTTP version header 2025-11-25 Initialize version Not supplied Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-29 02:51:18 UTC 2026-10-30 13:25:20 UTC	32
opencode 2.2.0	2025-11-25	2025-11-25 Negotiated	Request succeeded	initialize Identity source clientInfo HTTP version header Not supplied Initialize version 2025-11-25 Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-29 02:51:18 UTC 2026-10-30 13:25:19 UTC	31
Unidentified client Release unknown	2025-11-25	2025-11-25 Version accepted	Request succeeded	Per-request version Identity source unknown HTTP version header 2025-11-25 Initialize version Not supplied Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-29 02:33:38 UTC 2026-10-29 02:33:38 UTC	1
pi 1.4.0	2025-11-25	2025-11-25 Negotiated	Request succeeded	initialize Identity source clientInfo HTTP version header Not supplied Initialize version 2025-11-25 Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-29 02:33:37 UTC 2026-10-29 02:33:37 UTC	1
Unidentified client Release unknown	2025-11-25	2025-11-25 Version accepted	Request succeeded	Per-request version Identity source unknown HTTP version header 2025-11-25 Initialize version Not supplied Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-28 20:43:25 UTC 2026-10-28 23:28:37 UTC	9
pi 1.4.0	2025-11-25	2025-11-25 Negotiated	Request succeeded	initialize Identity source clientInfo HTTP version header Not supplied Initialize version 2025-11-25 Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-28 20:43:25 UTC 2026-10-28 23:28:37 UTC	7
opencode latest/2.2.0/cli	2025-11-25	2025-11-25 Version accepted	Request succeeded	Per-request version Identity source user-agent HTTP version header 2025-11-25 Initialize version Not supplied Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-28 20:51:36 UTC 2026-10-28 20:51:36 UTC	1
opencode 2.2.0	2025-11-25	2025-11-25 Negotiated	Request succeeded	initialize Identity source clientInfo HTTP version header Not supplied Initialize version 2025-11-25 Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-28 20:51:36 UTC 2026-10-28 20:51:36 UTC	1
codex-mcp-client 0.160.0	2025-06-18	2025-06-18 Version accepted	Unsupported method	Per-request version Identity source user-agent HTTP version header 2025-06-18 Initialize version Not supplied Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"] Error -32601 Method not found: resources/list	2026-10-22 01:31:16 UTC 2026-10-22 01:31:17 UTC	4
codex-mcp-client 0.160.0	2025-06-18	2025-06-18 Negotiated	Request succeeded	initialize Identity source clientInfo HTTP version header Not supplied Initialize version 2025-06-18 Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-22 01:31:12 UTC 2026-10-22 01:31:17 UTC	3
codex-mcp-client 0.160.0	2025-06-18	2025-06-18 Version accepted	Request succeeded	Per-request version Identity source user-agent HTTP version header 2025-06-18 Initialize version Not supplied Metadata version Not supplied Server-supported versions ["2026-07-28","2025-11-25","2025-06-18","2025-03-26"]	2026-10-22 01:31:14 UTC 2026-10-22 01:31:15 UTC	2