# anthropic/claude-haiku-4-5 has not changed while observed

From 2026-09-26 to 2026-10-04, there was no day on which the answers changed.
**If your system misbehaves, a change in this model does not explain it.**

| Observed via | **The provider's official API, called directly** (a change here is a change in the model) |
|---|---|
| First observed | 2026-09-26 (we know nothing before this) |
| Last observed | 2026-10-04 |
| Days observed | 9 |
| Days with a change | 0 |
| Same answer when asked twice on the same day (last observed day) | 78% |

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## If something is still wrong, look here

- Changes to your own prompts or downstream code (check your deploy history)
- Changes in the product layer (coding assistants, SDKs and so on). **Products change even when the API does not**
- The endpoint you call may not be the one observed here

---

## About this record

- We ask the same fixed 100 questions (probe set `en-v2`) once a day at temperature 0, **twice each**
- The probe set is frozen (SHA-256 `d967055a5389e58a8767faf6be90996f…`). **It has never been changed**
- **What counts as a change**: we look at four things
    1. Content: the answer to a question that was stable changed (the threshold is computed daily from how much this model wobbles)
    2. Length: the distribution of answer lengths moved far beyond the same-day wobble
    3. Refusal: the way it refuses questions near a boundary changed
    4. Wobble: the rate of identical answers when asked twice on the same day itself changed
- When comparing two days, **we only compare questions observed on both days** (so a network failure is not mistaken for a change)
- **Response time (latency) is not used.** It mixes in conditions on our side
- Everything is free to read for the whole period. The most recent few days may become paid in the future.
- The data is licensed under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). Please credit https://aimodelrecord.com when you use it.

## Badge

Paste this into your README. It shows whether this model has changed, and links here.

```
[![anthropic/claude-haiku-4-5](https://aimodelrecord.com/badge/anthropic/claude-haiku-4-5.svg)](https://aimodelrecord.com/m/anthropic/claude-haiku-4-5.html)
```