spend_control is no longer accepted

What changed

Usually ignored rather than rejected, so the call succeeds and does something subtly different.

Affects spend_control on CreateAgentSessionParams reachable from 1 operation. Grep for it: nothing else will tell you.

Who is affected

Code that sends OpenAI's CreateAgentSessionParams objects, used by 1 OpenAI operation.

Before and after

Code that breaks

await client.post("/…", {
  // spend_control is now ignored, not rejected
  spend_control: value,
});

Based on OpenAI’s published API specification. How severity is decided.