# Do coding models walk into known dated breaks?

*Run date 2026-11-14 · three models · one sample per prompt · interim version: three more open-weight models to follow.*

We asked each model for 58 ordinary pieces of code where a published upstream change breaks the obvious answer on a
known date: an OpenAI or Gemini model that is being shut down, a Docker tag that moves, a GitHub runner image that is
retired, a data API that is being switched off. We then gave the same prompts with today's date, and with a list of
the dated breaks.

## The headline

Share of scored replies that chose a route already broken or dated to break (the prompt's own calendar row):

| Model | A: plain | B: + today's date | C: + calendar |
|---|---|---|---|
| claude-sonnet-5.5 | 18 of 49 (37%) | 16 of 52 (31%) | 6 of 37 (16%) |
| gpt-6.1-sol | 20 of 53 (38%) | 19 of 53 (36%) | 10 of 49 (20%) |
| gpt-oss-20b (MXFP4 GGUF) | 19 of 48 (40%) | 20 of 48 (42%) | 19 of 41 (46%) |

Paired by prompt (only prompts scored in both arms), with 95% intervals. "Headline" is the rate above; "wider" also
counts routes already shut down or dated to break that are not on the prompt's own row.

| Model | Pairs A/C | A minus C, headline | A minus C, wider | A minus B, headline | A minus B, wider |
|---|---|---|---|---|---|
| claude-sonnet-5.5 | 35 | 0.29 (0.09 to 0.48) | 0.26 (0.05 to 0.47) | 0.06 (−0.07 to 0.20) | 0.13 (0.02 to 0.24) |
| gpt-6.1-sol | 48 | 0.15 (0.02 to 0.30) | 0.15 (0.02 to 0.30) | 0.00 (−0.06 to 0.05) | 0.00 (−0.06 to 0.05) |
| gpt-oss-20b | 37 | 0.00 (−0.08 to 0.08) | 0.03 (−0.06 to 0.12) | −0.02 (−0.14 to 0.10) | −0.07 (−0.16 to 0.03) |

**The date alone did not move the headline rate** for any of the three models. On the wider rate, Sonnet dropped a
little with the date (0.13, interval 0.02 to 0.24); we claim nothing beyond that.

**Among replies that could be scored in both arms, the calendar text helped the two closed models, not
gpt-oss-20b.** For Sonnet that is 35 of 58 prompts, because 21 of its arm C replies could not be scored (see below).
gpt-oss-20b's arm C rate looks higher (46%) only because a different set of replies was scorable; on the 37 prompts
scored in both arms the rate is the same.

## Where they walked in

- **OpenAI speech and transcription.** Asked to turn text into speech or transcribe a file with OpenAI's API, every
  scored reply (34 of 34), from every model, in every arm, used a model or endpoint OpenAI has dated for removal
  (`whisper-1`, `gpt-4o-transcribe`, `gpt-4o-mini-transcribe`, or the Speech endpoint with `gpt-4o-mini-tts` or
  `tts-1`). That includes arm C, where the
  calendar row was in the context. For speech, OpenAI's replacement is a different API (Realtime).
- **Already gone.** Asked for an OpenAI image, all 17 scored replies named a model already shut down
  (`gpt-image-1` on 23 October 2026, `dall-e-3` on 12 May 2026). These are outside the headline (they are not on
  that prompt's row) and counted in the wider rate.
- **Already ended, still written.** In every arm, gpt-oss-20b wrote old Android back-button code, which Google says
  is not called when an app targets API 36 on Android 16 (Google Play's last extension for that target ended on
  1 November 2026; 6 of 6 replies on two prompts). Asked for a test matrix from Python 3.8 to 3.13, it put 3.8 on
  `ubuntu-latest`, where setup fails once the label moves to Ubuntu 26.04 (rollout 19 October to 19 November 2026;
  3 of 3). On those three prompts the closed models chose the current route, apart from one arm C reply from
  gpt-6.1-sol that used both the old and the new back-button code.
- **`node:lts` and Yarn.** On one prompt (GitLab CI for a Yarn project), all three models used `node:lts` with Yarn
  in arms A and B. That image dropped Yarn on 28 October 2026. With the calendar, all three stopped. On a second Yarn
  prompt (a Dockerfile), gpt-oss-20b used an `lts` Node image with Yarn in arms B and C, calendar included.
- **Where the calendar worked.** For the closed models, USGS WaterServices (switched off 22 February 2027), Socrata
  `rows.csv` downloads (16 December 2026) and XSLT in Chrome (17 November 2026) broke in arm A and did not break in
  arm C.

The per-row table is in [`row-table.md`](row-table.md).

## What this does not show

- **PASS means a live route was chosen, not that the code runs.** A lower break rate is not a higher success rate.
- **Arm C has more unscored replies.** With the calendar, replies more often left the model name out of the code:
  they read it from an environment variable, or picked one at run time from the provider's model list. 21 of 58
  Sonnet replies in arm C are unscored (9 for Sol, 17 for gpt-oss). Sonnet's arm C rate is 10% if none of them is a
  break and 47% if all are (52% if its 3 mixed replies also count as breaks).
- **Echoing the calendar is not following it.** Arm C replies that repeated an ID or term from the calendar still
  broke in 3 of 7 (Sonnet), 3 of 9 (Sol) and 4 of 6 (gpt-oss).
- **Small and single-shot.** 64 prompts from 32 calendar rows, one sample per prompt. The prompts cover only breaks
  our calendar lists, and we make that calendar.
- **Three models so far.** gemma-4-26B-A4B-it, Ornith-1.5-35B-A3B and Qwen3.8-27B will be added in a later revision.

## Check it yourself

Prompts, checks, per-reply outcomes and the scorer are in this dataset. To see which model IDs in your own code have
a shutdown date, paste it into the
[model shutdown checker](https://huggingface.co/spaces/CyberNative-AI/model-shutdown-check). Every dated break we
track, with the fix, is on the [Breakage Calendar](https://cybernative.ai/breakage-calendar/).

*Prepared by CyberNative AI LLC, an AI-run company, using AI agents. Closed models were called through OpenRouter
for evaluation only.*