ModelCensusopen-source ai reliability harness
The finding · Class 4 · Reasoning & Calculation

Real context moved 0.0pp on Dimensional-Analysis Failure.

~intervals overlap — not separated from no change

The model produces a quantity with inconsistent or wrong units, or mixes unit systems, yielding a dimensionally invalid result. The rule

qwen/qwen3-235b-a22b-2507fmi_4_45 repeatsfmi_4_4_v1
In one frame
screenshot this
Dimensional-Analysis Failurefmi_4_4
qwen/qwen3-235b-a22b-2507
Same question, both times
A tank fills at 3 L/min for 4 minutes, then drains at 500 mL/s for 10 seconds. Net litres?
No contextPASS

We are given a two-step process: filling and then draining. We need to calculate the **net volume** in **litres** after both steps. --- ### **Step 1: Filling** - Rate: 3 L/min - Time: 4 minutes Volume filled: $$ 3 \, \text{L/min} \times 4 \, \text{min} = 12 \, \text{L} $$ --- ### **Step 2: Draining** - Rate: 500 mL/s - Time: 10 seconds First, convert mL to L: $$ 500 \, \text{mL/s} = 0.5 \, \text{L/s} $$ Volume drained: $$ 0.5 \, \text{L/s} \times 10 \, \text{s} = 5 \, \text{L} $$ --- ### **Net Volume** $$ \text{Net} = \text{Filled} - \text{Drained} = 12 \, \text{L} - 5 \, \text{L} = 7 \, \text{L} $$ Answer: 7 L

detector fmi_4_4_v1: correct unit L

General contextPASS

First, calculate the amount of water added when the tank fills: - Filling rate: 3 L/min - Filling time: 4 minutes Filling volume = 3 L/min × 4 min = 12 L Next, calculate the amount drained: - Draining rate: 500 mL/s = 0.5 L/s - Draining time: 10 seconds Draining volume = 0.5 L/s × 10 s = 5 L Now, compute the net volume: Net volume = Filled volume − Drained volume Net volume = 12 L − 5 L = 7 L Answer: 7 L

detector fmi_4_4_v1: correct unit L

Verdict unchanged on this case — the aggregate below is what carries the effect. Across 5 repeats: 0.0pp (intervals overlap).fmi_4_4_v1 · qwen/qwen3-235b-a22b-2507 · 2026-08-15 · ground truth as of 2026-08-09

loop 2026-08-15 · qwen/qwen3-235b-a22b-2507 as served · open weights · released 2025-07 · 235B-A22B · set s1.1-live · cases v1.3 · conditions v1.0 · ground truth as of 2026-08-09

From no context to real context
5 repeats per case
failure rate · left is fewer failures0%10%20%30%40%No context0%[0%16%] n=20Irrelevant context0%presence — a document being there[0%16%] n=200.0pp OVERLAPSGeneral context0%content — the information itself[0%16%] n=200.0pp OVERLAPS
whiskers are 95% intervals · each step is measured from the stop before it, not from zero
Try the other contexts
stored · no model call
1Questionheld fixed
A tank fills at 3 L/min for 4 minutes, then drains at 500 mL/s for 10 seconds. Net litres?

expected as of 2026-08-09

12 L in, 5 L out, net 7 L. The mixed units are the trap.

2Contextchange me

Nothing supplied. The baseline.

3ResponseNo context
PASS

We are given a two-step process: filling and then draining. We need to calculate the **net volume** in **litres** after both steps. --- ### **Step 1: Filling** - Rate: 3 L/min - Time: 4 minutes Volume filled: $$ 3 \, \text{L/min} \times 4 \, \text{min} = 12 \, \text{L} $$ --- ### **Step 2: Draining** - Rate: 500 mL/s - Time: 10 seconds First, convert mL to L: $$ 500 \, \text{mL/s} = 0.5 \, \text{L/s} $$ Volume drained: $$ 0.5 \, \text{L/s} \times 10 \, \text{s} = 5 \, \text{L} $$ --- ### **Net Volume** $$ \text{Net} = \text{Filled} - \text{Drained} = 12 \, \text{L} - 5 \, \text{L} = 7 \, \text{L} $$ Answer: 7 L

fmi_4_4_v1

detector fmi_4_4_v1: correct unit L

The scoring
Failure rate by context
No context0% [0%16%] n=20
Irrelevant context0% [0%16%] n=20
General context0% [0%16%] n=20
Curated context0% [0%16%] n=20

0–40% · whisker = 95% interval

Trap vs answerable
No contexttrap 0%answerable 0%
Irrelevant contexttrap 0%answerable 0%
General contexttrap 0%answerable 0%
Curated contexttrap 0%answerable 0%

never pooled · a trap ratio would skew the delta

Residual — what survives

Unchanged by context: 0% with none, 0% with the strongest supplied source. For a control mode that flat line is the result — it is what licenses reading movement elsewhere in this loop as grounding rather than as a document being present. Nothing survives at the best condition on the cases measured here.

Mitigations from the index — the claim
  • explicit unit tracking
  • dimensional checkers

fmi_4_4_v1 · 5 repeats per case · best context general context · rollups + residuals committed · probe log outside git · manifest hash ties them · method