Qwen3.5 Plus 2026-04-20 Behavioral Fingerprint
How Qwen's Qwen3.5 Plus 2026-04-20 answers one-word probe questions at temperature 1.0 — random numbers, colors, animals, coin flips — measured over 448 valid samples in the open dataset of "One Token Is Enough" (arXiv:2607.10252).
Vendor
Qwen
Data generated
2026-07-08
Probe cells
15
Valid samples
448
Randomness score
18 / 100
Mean normalized entropy across cells, 0–100. 100 would be a uniform-random baseline; real models score far lower.
Signature answers
Favorite random number (1–100)
42
29 / 30 answers
Favorite color
blue
27 / 30 answers
Coin flip: heads
92%
Share of heads across coin-flip cells.
Answer distributions by probe cell
Empirical distributions of normalized one-word answers, per task and language. H is the Shannon entropy in bits; the uniform baseline is log2 of the answer-domain size.
Coin flip · English
n = 30 · H = 0.65 bit · uniform baseline 1.00 bit
| Answer | Count | Share |
|---|---|---|
| heads | 25 | 83.3% |
| tails | 5 | 16.7% |
Coin flip · Chinese
n = 30 · H = 0.00 bit · uniform baseline 1.00 bit
| Answer | Count | Share |
|---|---|---|
| heads | 30 | 100.0% |
Favorite number · English
n = 30 · H = 1.11 bit · uniform baseline 13.29 bit
| Answer | Count | Share |
|---|---|---|
| 42 | 19 | 63.3% |
| 7 | 10 | 33.3% |
| 0 | 1 | 3.3% |
Favorite number · Chinese
n = 28 · H = 0.89 bit · uniform baseline 13.29 bit
| Answer | Count | Share |
|---|---|---|
| 7 | 22 | 78.6% |
| 42 | 5 | 17.9% |
| 0 | 1 | 3.6% |
Random animal · English
n = 30 · H = 1.56 bit · uniform baseline 5.64 bit
| Answer | Count | Share |
|---|---|---|
| cat | 19 | 63.3% |
| tiger | 5 | 16.7% |
| fox | 4 | 13.3% |
| zebra | 1 | 3.3% |
| elephant | 1 | 3.3% |
Random animal · Chinese
n = 30 · H = 0.83 bit · uniform baseline 5.64 bit
| Answer | Count | Share |
|---|---|---|
| 猫 | 26 | 86.7% |
| 狮子 | 1 | 3.3% |
| 大象 | 1 | 3.3% |
| 狗 | 1 | 3.3% |
| 虎 | 1 | 3.3% |
Random city · English
n = 30 · H = 1.59 bit · uniform baseline 5.64 bit
| Answer | Count | Share |
|---|---|---|
| paris | 16 | 53.3% |
| tokyo | 8 | 26.7% |
| kyoto | 5 | 16.7% |
| seattle | 1 | 3.3% |
Random city · Chinese
n = 30 · H = 2.30 bit · uniform baseline 5.64 bit
| Answer | Count | Share |
|---|---|---|
| 北京 | 12 | 40.0% |
| 巴黎 | 9 | 30.0% |
| paris | 3 | 10.0% |
| 上海 | 2 | 6.7% |
| 柏林 | 1 | 3.3% |
| 东京 | 1 | 3.3% |
| 纽约 | 1 | 3.3% |
| 深圳 | 1 | 3.3% |
Random color · English
n = 30 · H = 0.56 bit · uniform baseline 4.91 bit
| Answer | Count | Share |
|---|---|---|
| blue | 27 | 90.0% |
| red | 2 | 6.7% |
| azure | 1 | 3.3% |
Random color · Chinese
n = 30 · H = 1.14 bit · uniform baseline 4.91 bit
| Answer | Count | Share |
|---|---|---|
| 蓝 | 18 | 60.0% |
| 红 | 11 | 36.7% |
| 绿 | 1 | 3.3% |
Random letter · English
n = 30 · H = 2.19 bit · uniform baseline 4.70 bit
| Answer | Count | Share |
|---|---|---|
| z | 9 | 30.0% |
| x | 9 | 30.0% |
| q | 7 | 23.3% |
| k | 3 | 10.0% |
| m | 1 | 3.3% |
| b | 1 | 3.3% |
Random number 1-10 · English
n = 30 · H = 0.00 bit · uniform baseline 3.32 bit
| Answer | Count | Share |
|---|---|---|
| 7 | 30 | 100.0% |
Random number 1-10 · Chinese
n = 30 · H = 0.00 bit · uniform baseline 3.32 bit
| Answer | Count | Share |
|---|---|---|
| 7 | 30 | 100.0% |
Random number 1-100 · English
n = 30 · H = 0.21 bit · uniform baseline 6.64 bit
| Answer | Count | Share |
|---|---|---|
| 42 | 29 | 96.7% |
| 73 | 1 | 3.3% |
Random number 1-100 · Chinese
n = 30 · H = 0.00 bit · uniform baseline 6.64 bit
| Answer | Count | Share |
|---|---|---|
| 42 | 30 | 100.0% |
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Distributions: Tomáš Bruckner, "One Token Is Enough" (arXiv:2607.10252), official dataset Zenodo DOI 10.5281/zenodo.21278557, licensed CC-BY-4.0. Collected via OpenRouter at temperature 1.0 under the paper's fixed minimal one-word system prompt; answer keys are re-normalized with the checker's pipeline (color aliases, number words, coin h/t) so live probes are directly comparable.