Model retirements · OpenAI API · checked

ft-o4-mini-2025-04-16 shutdown on 23 October 2026

OpenAI shuts down ft-o4-mini-2025-04-16 on the OpenAI API on 23 October 2026 and recommends gpt-5.6-terra as the replacement. No price ratio: a fine-tune's replacement is a base model you would fine-tune again or prompt instead, so a per-token ratio would compare unlike things; none is given. OpenAI's deprecation page documents no API changes for this move. Record your answers before 23 October 2026: after that nobody can ask ft-o4-mini-2025-04-16 again.

Find every place your code and config name it, with this page's facts beside each:

$ npx --allow-git=root github:agentwares/model-migrate scan

npx --allow-git=root github:agentwares/model-migrate scan lists every model ID in your code and config that has a shutdown date, with its replacement, price ratio and this page's link. It needs no account and no API key, reads your files on your machine and sends nothing; its one request fetches this data. Free and MIT licensed.

The facts

Platform
OpenAI API
Model ID
ft-o4-mini-2025-04-16Fine-tuned models built on this base, with IDs starting ft:o4-mini-2025-04-16:.
Announced
22 April 2026
Shutdown
23 October 2026
Recommended replacement
gpt-5.6-terra
List price per million tokens, input / output
A fine-tune's replacement is a base model you would fine-tune again or prompt instead, so a per-token ratio would compare unlike things; none is given.

Prices are the provider's list prices for the standard tier, text input and the shortest context tier. A per-token ratio leaves out how many tokens each model spends on the same prompt; only your own prompts show that.

What changes when you move

OpenAI's deprecation page lists no parameter or API changes for this move. The model's answers still change: a replacement is a different model.

How to test the replacement on your own prompts

  1. Find every call that names ft-o4-mini-2025-04-16: npx --allow-git=root github:agentwares/model-migrate scan prints each file and line.
  2. Before 23 October 2026, record what ft-o4-mini-2025-04-16 answers on a sample of your real prompts, with the token counts OpenAI reports, on your own key: npx --allow-git=root github:agentwares/model-migrate capture prompts.jsonl --model "ft:o4-mini-2025-04-16:…". After the shutdown that record cannot be made.
  3. Run the same prompts on gpt-5.6-terra, a cheaper sibling and a model from another provider, and compare with checks that need no judge: exact or normalised match, JSON validity and schema, tool-call names and arguments, refusals and length. npx --allow-git=root github:agentwares/model-migrate compare does this on your keys.
  4. Price the move with the token counts each provider reports for those prompts, not with the list price alone; compare reports the cost per 1,000 calls.

Keep testing until the date

capture and compare run on your keys and keep everything on your machine. To re-run the same prompts against your own endpoint whenever a provider ships a model, with the history kept, npx --allow-git=root github:agentwares/model-migrate export --agentcheck writes them as traces that agentcheck imports onto a target you monitor there. On its Pro plan they become checks that re-run when a provider ships a model, with 90 days of history.

Migration watch is not built. It would re-run your captured prompts on each replacement and each new model until 23 October 2026, with no endpoint needed, and email you what changed. If you would pay for that, say so with one click. The click is counted; nothing else is sent or stored.

Also shutting down on 23 October 2026

Other OpenAI API retirements

Every announced shutdown, by date

Sources

Built only from the providers' own pages. No vendor intent is implied: a date is what the page says on the day it was read. Data: /models/retirements.json.

model-migrate is a free tool from agentcheck, which re-runs an agent's checks when a provider ships a model and replays recorded traces nightly, so a model change that breaks it arrives as one diff by email.