Live investigation (direct from a VPN host to the 2023 R2 historian's real WCF
port) showed the certificate transport + NegotiateAuthentication auth work
cross-platform, and that the event-read chain needs the 0x501 event connection
mode for CM_EVENT RegisterTags to succeed (0x402/0x401 fail). Even with
registration succeeding over a window that has events, StartEventQuery returns a
0-row header and long-polls — the same server-side per-connection row gate proven
for gRPC. Adds: EventReadConnectionModeOverride (diagnostic), and spike knobs —
cross-platform cert gate, version-check bypass, per-call timeout, overall budget
with phase-diagnostic dump, connection-mode override.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Joseph Doherty
de8d5e91ce