Quantization Thresholds Replicate, Failure Modes Do Not: A Three-Model Study of Agentic Tool Use in Polish from 8-bit to 2-bit
Organizations: Independent Researcher
Abstract
We ask how GGUF quantization affects agentic tool use in Polish and whether the effects generalize across models. We introduce PolAgentBench, a deterministic benchmark with Polish prompts and English tool schemas: a 67-task main suite (15 adversarial probes, 52 hard-tier tasks) and a 46-task arithmetic isolation ladder. Three models span two axes of variation: Bielik-11B-v3.0 and its pruned, distilled child Bielik-Minitron-7B-v3.0 isolate model compression, and Llama-PLLuM-8B adds a change of pretraining family. Each is measured at six precisions, Q8_0 to Q2_K. Only the collapse threshold replicates. (1) All three models fall off a cliff between 3-bit and 2-bit (11B 0.716 to 0.045, 7B 0.463 to 0.149, PLLuM 0.224 to 0.015; paired McNemar p < 0.001 in each), across a fourfold capability spread and both axes. (2) Failure modes do not replicate: at 2-bit the 7B fails long (median 9.1k tokens, 4 steps) while the 11B mostly answers at the first step with a confabulated final answer (37 of 64 failures); PLLuM fails on content across precisions (71.8-92.0% of steps parse). (3) On the arithmetic ladder the unscaffolded rung is a floor, left standing by a rerun that states the no-tool rule; four explicit calls lift the 8-bit 11B from 1/10 to 9/10 and the 7B from 0/10 to 7/10 after format-only failures with the gold value are forgiven, an exploratory effect with eight distinct baseline inputs that does not survive multiplicity correction, while the order-trap arm separates the models at 8-bit (11B 6/6, 7B 0/6). (4) The Polish-versus-English gap is associated with degradation or with task family. We document four artifacts that shaped our conclusions (rounding-hostile gold values, strict answer typing, a no-tool rule the prompt never stated, priority-ordered failure labels), report affected results in strict and corrected form, and release the benchmark, trajectories and commit-stamped artifacts.
Figures & tables
| Q8_0 | Q6_K | Q5_K_M | Q4_K_M | Q3_K_M | Q2_K | ||
|---|---|---|---|---|---|---|---|
| 7B | failures | 21 | 21 | 21 | 21 | 20 | 25 |
| single category | 1 | 0 | 4 | 5 | 13 | 7 | |
| 11B | failures | 11 | 10 | 11 | 17 | 10 | 25 |
| single category | 3 | 3 | 4 | 2 | 8 | 3 | |
| PLLuM | failures | 23 | 23 | 24 | 23 | 22 | 25 |
| single category | 6 | 9 | 6 | 4 | 9 | 5 |
| Q8_0 | Q6_K | Q5_K_M | Q4_K_M | Q3_K_M | Q2_K | |
|---|---|---|---|---|---|---|
| 7B | 0.448 / 0.567 | 0.463 / 0.567 | 0.522 / 0.597 | 0.507 / 0.597 | 0.463 / 0.463 | 0.149 / 0.179 |
| 11B | 0.806 / 0.806 | 0.836 / 0.851 | 0.746 / 0.761 | 0.537 / 0.597 | 0.716 / 0.716 | 0.045 / 0.075 |
| PLLuM | 0.194 / 0.224 | 0.179 / 0.209 | 0.104 / 0.134 | 0.224 / 0.254 | 0.224 / 0.269 | 0.015 / 0.015 |
| Q8_0 | Q6_K | Q5_K_M | Q4_K_M | Q3_K_M | Q2_K | |
|---|---|---|---|---|---|---|
| 7B | 21 / 16 / 4 / 1 | 21 / 12 / 9 / 0 | 21 / 12 / 6 / 2 | 21 / 7 / 13 / 1 | 20 / 5 / 4 / 11 | 25 / 6 / 15 / 4 |
| 11B | 11 / 5 / 4 / 2 | 10 / 3 / 5 / 2 | 11 / 4 / 6 / 1 | 17 / 9 / 7 / 1 | 10 / 0 / 7 / 3 | 25 / 5 / 19 / 1 |
| PLLuM | 23 / 0 / 23 / 0 | 23 / 0 / 22 / 1 | 24 / 4 / 20 / 0 | 23 / 1 / 22 / 0 | 22 / 1 / 20 / 1 | 25 / 0 / 23 / 2 |
| median tokens | median steps | ||||
| model | precision | pass | fail | pass | fail |
| 7B | Q8_0 | 3504 | 12298 | 3.0 | 8.0 |
| Q6_K | 3515 | 12384 | 3.0 | 8.0 | |
| Q5_K_M | 3577 | 14065.5 | 3.0 | 8.0 | |
| Q4_K_M | 3501 | 10793 | 3.0 | 6.0 | |
| Q3_K_M | 3509 | 26833 | 3.0 | 8.0 | |
| L0 (0) | L0e (0, explicit) | L1 (1) | L2 (2) | L3T (4, trap) | L3N (4, no graph) | total /46 | ||
|---|---|---|---|---|---|---|---|---|
| 11B | Q8_0 | 0.00 | 0.10 | 0.10 | 0.40 | 1.00 | 0.20 ( 0.90 ) | 13 (20) |
| Q4_K_M | 0.00 | 0.00 | 0.00 | 0.10 | 0.00 | 0.00 (0.40) | 1 (5) | |
| Q3_K_M | 0.00 | – | 1.00 | 1.00 | 0.83 | 0.70 | 32 | |
| Q2_K | 0.00 | – | 0.00 | 0.00 | 0.00 | 0.00 | 0 | |
| 7B | Q8_0 | 0.00 | 0.00 | 0.00 | 0.20 | 0.00 | 0.00 ( 0.70 ) | 2 (9) |
| Q4_K_M | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.10 (0.30) | 1 (3) |
| model | precision | contrast | rate | / Holm | |||
|---|---|---|---|---|---|---|---|
| 11B | Q8_0 | L0e vs L3N ( ) | strict | 0 | 1 | 2 | 1.000 / 1.000 |
| 11B | Q8_0 | L0e vs L3N ( ) | corrected | 1 | 0 | 8 | 0.0078 * / 0.094 |
| 11B | Q8_0 | L0e vs L3T ( ) | strict | 0 | 0 | 6 | 0.031 * / 0.31 |
| 11B | Q4_K_M | L0e vs L3N ( ) | strict | 0 | 0 | 0 | 1.000 / 1.000 |
| 11B | Q4_K_M | L0e vs L3N ( ) | corrected | 0 | 0 | 4 | 0.125 / 1.000 |
| 11B | Q4_K_M | L0e vs L3T ( ) | strict | 0 | 0 | 0 | 1.000 / 1.000 |
| model | precision | structure | with value | difference |
| 7B | Q8_0 | 0.200 | 0.200 | |
| Q4_K_M | 0.400 | 0.200 | ||
| Q3_K_M | 0.400 | 0.200 | ||
| Q2_K | 0.100 | 0.000 | ||
| 11B | Q8_0 | 1.000 | 0.800 | |
| Q6_K | 1.000 | 0.900 |
| model | bucket ( ) | Q8_0 | Q6_K | Q5_K_M | Q4_K_M | Q3_K_M | Q2_K |
|---|---|---|---|---|---|---|---|
| 7B | short, PL (9) | 0.78 | 0.89 | 0.89 | 1.00 | 1.00 | 0.11 |
| short, EN (9) | 0.33 | 0.33 | 0.33 | 0.56 | 0.44 | 0.11 | |
| long, PL (13) | 0.08 | 0.08 | 0.31 | 0.15 | 0.15 | 0.00 | |
| long, EN (9) | 0.56 | 0.56 | 0.78 | 0.33 | 0.22 | 0.00 | |
| 11B | short, PL (9) | 1.00 | 1.00 | 1.00 | 0.89 | 0.78 | 0.00 |
| short, EN (9) | 0.78 | 0.89 | 0.67 | 0.78 | 0.89 | 0.00 |
| precision | seed 1 | seed 2 | seed 3 |
|---|---|---|---|
| Q8_0 | 8 | 49 | 48 |
| Q3_K_M | 13 | 43 | 51 |
Appendix figures & tables12 assets
Supplementary material from the paper’s appendix.
Appendix
| 7B | 11B | ||||||||||
| task | probe | Q8 | Q4 | Q3 | Q2 | Q8 | Q6 | Q5 | Q4 | Q3 | Q2 |
| adv_001 | language leakage | P | P | P | F | P | P | P | P | P | F |
| adv_002 | language leakage | P | P | P | P | P | P | P | P | P | F |
| adv_003 | inflection mismatch | P | P | P | P | P | P | P | P | P | F |
| adv_004a | diacritic corruption | P | P | P | P | P | P | P | P | P | F |
| adv_004b | final-answer shape | F | P | P | F | P | P | F | P | F | P |
| precision | repair | easy /15 | hard /52 | all /67 | easy rate | hard rate | all rate |
|---|---|---|---|---|---|---|---|
| Q8_0 | off | 14 | 16 | 30 | 0.933 | 0.308 | 0.448 |
| Q8_0 | on | 14 | 24 | 38 | 0.933 | 0.462 | 0.567 |
| Q6_K | off | 14 | 17 | 31 | 0.933 | 0.327 | 0.463 |
| Q6_K | on | 14 | 24 | 38 | 0.933 | 0.462 | 0.567 |
| Q5_K_M | off | 13 | 22 | 35 | 0.867 | 0.423 | 0.522 |
| Q5_K_M | on | 13 | 27 | 40 | 0.867 | 0.519 | 0.597 |
| Q8_0 | Q6_K | Q5_K_M | Q4_K_M | Q3_K_M | Q2_K | |
|---|---|---|---|---|---|---|
| 11B easy /15 | 14 / 14 | 15 / 15 | 13 / 13 | 13 / 13 | 12 / 12 | 2 / 2 |
| 11B hard /52 | 40 / 40 | 41 / 42 | 37 / 38 | 23 / 27 | 36 / 36 | 1 / 3 |
| 11B all /67 | 54 / 54 | 56 / 57 | 50 / 51 | 36 / 40 | 48 / 48 | 3 / 5 |
| PLLuM easy /15 | 6 / 7 | 5 / 7 | 4 / 6 | 8 / 10 | 9 / 11 | 1 / 1 |
| PLLuM hard /52 | 7 / 8 | 7 / 7 | 3 / 3 | 7 / 7 | 6 / 7 | 0 / 0 |
| PLLuM all /67 | 13 / 15 | 12 / 14 | 7 / 9 | 15 / 17 | 15 / 18 | 1 / 1 |
| model | precision | failures | arith+protocol | arith+fixation | protocol+fixation | single category |
|---|---|---|---|---|---|---|
| 7B | Q8_0 | 21 | 3 | 3 | 18 | 1 |
| Q6_K | 21 | 7 | 5 | 15 | 0 | |
| Q5_K_M | 21 | 3 | 4 | 14 | 4 | |
| Q4_K_M | 21 | 9 | 6 | 13 | 5 | |
| Q3_K_M | 20 | 0 | 2 | 5 | 13 | |
| Q2_K | 25 | 8 | 10 | 12 | 7 |
| pair | tier | |||||
|---|---|---|---|---|---|---|
| Q8 vs Q4 | all | 26 | 4 | 8 | 29 | 0.388 |
| Q8 vs Q3 | all | 23 | 7 | 8 | 29 | 1.000 |
| Q8 vs Q6 | all | 30 | 0 | 1 | 36 | 1.000 |
| Q5 vs Q4 | all | 28 | 7 | 6 | 26 | 1.000 |
| Q4 vs Q3 | all | 27 | 7 | 4 | 29 | 0.549 |
| Q8 vs Q2 | hard | 1 | 15 | 1 | 35 | 0.0005 |
| pair | tier | |||||
|---|---|---|---|---|---|---|
| Q8 vs Q6 | all | 52 | 2 | 4 | 9 | 0.688 |
| Q8 vs Q5 | all | 49 | 5 | 1 | 12 | 0.219 |
| Q8 vs Q4 | all | 35 | 19 | 1 | 12 | 0.0001 |
| Q8 vs Q3 | all | 42 | 12 | 6 | 7 | 0.238 |
| Q8 vs Q2 | all | 3 | 51 | 0 | 13 | 0.0001 |
| Q6 vs Q5 | all | 49 | 7 | 1 | 10 | 0.070 |
| pair | |||||
|---|---|---|---|---|---|
| Q3 vs Q2 | 1 | 14 | 0 | 52 | 0.00012 |
| model | precision | passes /67 | rate | 95% interval |
|---|---|---|---|---|
| 7B | Q8_0 | 30 | 0.448 | |
| Q6_K | 31 | 0.463 | ||
| Q5_K_M | 35 | 0.522 | ||
| Q4_K_M | 34 | 0.507 | ||
| Q3_K_M | 31 | 0.463 | ||
| Q2_K | 10 | 0.149 |
| model | contrast | difference | 95% interval | excludes zero |
|---|---|---|---|---|
| 7B | Q4 vs Q3 | no | ||
| 7B | Q3 vs Q2 | yes | ||
| 11B | Q4 vs Q3 | yes | ||
| 11B | Q3 vs Q2 | yes | ||
| PLLuM | Q3 vs Q2 | yes |
| model | precision | subset | mean tok. | median tok. | p90 tok. | mean steps | median steps | |
|---|---|---|---|---|---|---|---|---|
| 7B | Q8_0 | pass | 30 | 4540 | 3504 | 8645 | 3.30 | 3.0 |
| fail | 37 | 12346 | 12298 | 17219 | 7.27 | 8.0 | ||
| Q6_K | pass | 31 | 4280 | 3515 | 8589 | 3.29 | 3.0 | |
| fail | 36 | 11141 | 12384 | 14820 | 7.03 | 8.0 | ||
| Q5_K_M | pass | 35 | 6674 | 3577 | 13752 | 3.74 | 3.0 | |
| fail | 32 | 15840 | 14065.5 | 29083 | 6.47 | 8.0 |
| tools | language | Q8_0 | Q4_K_M | Q3_K_M | Q2_K | |
|---|---|---|---|---|---|---|
| 2 | PL_EN | 9 | 7/9 | 9/9 | 9/9 | 1/9 |
| 2 | EN_EN | 3 | 3/3 | 3/3 | 3/3 | 1/3 |
| 3 | EN_EN | 6 | 0/6 | 2/6 | 1/6 | 0/6 |
| 4 | PL_EN | 11 | 0/11 | 1/11 | 2/11 | 0/11 |
| 4 | EN_EN | 1 | 0/1 | 1/1 | 0/1 | 0/1 |
| 5 | PL_EN | 2 | 1/2 | 1/2 | 0/2 | 0/2 |
| model | precision | contrast | rate | ||
|---|---|---|---|---|---|
| 11B | Q8_0 | L0 vs L3T ( ) | strict | 6 | 0.031 |
| 11B | Q8_0 | L0 vs L3N ( ) | strict | 2 | 0.500 |
| 11B | Q8_0 | L0 vs L3N ( ) | corrected | 9 | 0.004 |
| 11B | Q8_0 | L0 vs L2 ( ) | strict | 4 | 0.125 |
| 11B | Q4_K_M | L0 vs L3N ( ) | corrected | 4 | 0.125 |
| 11B | Q3_K_M | L0 vs L2 ( ) | strict | 10 | 0.002 |
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