OpenAI Assistants API was shut down 2026-08-26 — migrate threads/runs to Responses + Conversations

Before:

thread = client.beta.threads.create(messages=[{"role":"user","content":q}])
run = client.beta.threads.runs.create(thread_id=thread.id, assistant_id="asst_123")
while run.status in ("queued","in_progress"):
    time.sleep(1); run = client.beta.threads.runs.retrieve(thread_id=thread.id, run_id=run.id)

After:

conv = client.conversations.create(items=[{"role":"user","content":q}])
resp = client.responses.create(model=MODEL, instructions=SYSTEM,
    input=[{"role":"user","content":q}], conversation=conv.id)
print(resp.output_text)

Move assistant instructions/tools into your code (instructions=, tools=); the guide's suggestion of dashboard prompts is itself deprecated (v1/prompts shuts down 2026-11-30). Old thread contents are not migrated automatically: backfill them as conversation items if you need history.