Same root cause on Cursor Enterprise with Override OpenAI Base URL pointed at a company AI gateway (TrueFoundry), not Moonshot.
What worked for me: a custom model ID that did not match a Cursor catalog entry hit the gateway (verified with matching gateway usage + Cursor token-rate, not full model cost).
What broke after ~mid-October: the same pattern as this thread — once the name collides with / is treated as a built-in (Kimi family), Override Base URL stops applying, I get 404 / resource-not-found, and nothing reaches the gateway. Staff confirmation here matches what I see: built-in Kimi is Cursor-hosted; the override is ignored.
Ask: route by selection — custom/gateway models → Override Base URL; catalog models → Cursor when selected. Also please don’t reserve provider model IDs so BYOK cannot use the exact ID the gateway expects.
I’m filing a Feature Request for Enterprise gateway BYOK + Override Anthropic Base URL as well. Feature Request: https://forum.cursor.com/t/enterprise-byok-ai-gateway-built-ins-ignore-override-base-url-need-anthropic-override/175824?u=diego_parima