No change detected in anthropic/claude-sonnet-4-5
From 2026-10-31 to 2026-10-31, we didn't see a single day on which its answers changed. If your system is misbehaving, a change in this model isn't the explanation.
We stopped observing this model after 2026-10-31. The record up to that day is kept as is, and we know nothing about what happened after it.
| Observed via | The provider's official API, called directly (so a change here means the model changed) |
|---|---|
| First observed | 2026-10-31 (nothing before this date is known) |
| Last observed | 2026-10-31 |
| Days observed | 1 |
| Days with a change | 0 |
| Same answer on both calls (latest day) | 79% |
If something is still wrong, check these
- Changes to your own prompts or downstream code (check your deploy history)
- Changes in the product layer (coding assistants, SDKs and so on). Products can change even when the API doesn't
- The endpoint you're calling may not be the one we observe here
About this record
- Every day, we ask the same fixed set of 100 questions (probe set
en-v2) at temperature 0, twice each - The probe set is frozen (SHA-256
d967055a5389e58a8767faf6be90996f…) and has never been changed - What counts as a change: we look at four things
- Content: a question whose answer was stable gets a different answer (the threshold is recalculated daily from how much this model wobbles)
- Length: answer lengths shift well beyond the usual same-day wobble
- Refusals: the way it handles judgment calls changes
- Wobble: the share of questions that get the same answer twice changes
- When comparing two days, we only compare questions observed on both days (so a network failure isn't mistaken for a change)
- We don't use response time (latency), since it also reflects conditions on our end
- The entire record is free to read. Access to the most recent few days may become paid in the future.
- The data is licensed under CC BY 4.0. Please credit https://aimodelrecord.com when you use it.
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