ModelCensusopen-source ai reliability harness
The finding · Class 5 · Robustness & Consistency

Real context moved 0.0pp on Paraphrase Non-Invariance.

~intervals overlap — not separated from no change

Meaning-preserving paraphrases of the same question yield materially different answers. The rule

google/gemma-3-27b-itfmi_5_25 repeatsfmi_5_2_v1
In one frame
screenshot this
Paraphrase Non-Invariancefmi_5_2
google/gemma-3-27b-it
Same question, both times
How many bones are in the adult human body?
No contextPASS

The total number of bones in an adult human is **206**. However, it's a bit more nuanced than that! Here's a breakdown: * **Babies are born with around 300 bones.** These are mostly cartilage, which gradually fuses together as they grow. * **Fusion happens over time.** Many bones, especially in the skull, hands, and feet, start as separate pieces and fuse into single bones during childhood and adolescence. * **206 is the standard count for adults *after* this fusion is complete.** * **Sesamoid bones:** Some people have extra small bones called sesamoid bones (like the patella/kneecap) embedded in tendons. These aren't always counted in the 206, and the number can vary from person to person. So, while 206 is the generally accepted number, it's possible for some individuals to have slightly more due to these extra sesamoid bones.

detector fmi_5_2_v1: answers invariant across paraphrases

General contextPASS

This passage discusses regional variations in English vocabulary for a type of bread roll. It **does not contain information about the number of bones in an adult human**. The answer to your question is **206**. However, it's not found in the provided text.

detector fmi_5_2_v1: answers invariant across paraphrases

Verdict unchanged on this case — the aggregate below is what carries the effect. Across 5 repeats: 0.0pp (intervals overlap).fmi_5_2_v1 · google/gemma-3-27b-it · 2026-08-15 · ground truth as of 2026-08-09

loop 2026-08-15 · google/gemma-3-27b-it as served · open weights · released 2025-03 · 27B · set s1.3-live · cases v1.6 · 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%5%10%15%20%No context0%[0%11%] n=30Irrelevant context0%presence — a document being there[0%11%] n=300.0pp OVERLAPSGeneral context0%content — the information itself[0%11%] n=300.0pp 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
How many bones are in the adult human body?

expected as of 2026-08-09

206. 206 in a typical adult. Widely misremembered, which is what makes the phrasings diverge.

2Contextchange me

Nothing supplied. The baseline.

3ResponseNo context
PASS

The total number of bones in an adult human is **206**. However, it's a bit more nuanced than that! Here's a breakdown: * **Babies are born with around 300 bones.** These are mostly cartilage, which gradually fuses together as they grow. * **Fusion happens over time.** Many bones, especially in the skull, hands, and feet, start as separate pieces and fuse into single bones during childhood and adolescence. * **206 is the standard count for adults *after* this fusion is complete.** * **Sesamoid bones:** Some people have extra small bones called sesamoid bones (like the patella/kneecap) embedded in tendons. These aren't always counted in the 206, and the number can vary from person to person. So, while 206 is the generally accepted number, it's possible for some individuals to have slightly more due to these extra sesamoid bones.

fmi_5_2_v1

detector fmi_5_2_v1: answers invariant across paraphrases

The scoring
Failure rate by context
No context0% [0%11%] n=30
Irrelevant context0% [0%11%] n=30
General context0% [0%11%] n=30
Curated context20% [10%37%] n=30

0–60% · whisker = 95% interval

Trap vs answerable
No contexttrap 0%answerable 0%
Irrelevant contexttrap 0%answerable 0%
General contexttrap 0%answerable 0%
Curated contexttrap 50%answerable 5%

never pooled · a trap ratio would skew the delta

Residual — what survives

Supplying context did not reduce this failure, it increased it: 0% with no context against 20% under the strongest supplied source. What survives is therefore not a remainder but a substitution — the failures under context are 0 probes the detector still rejected. Nothing survives at the best condition on the cases measured here.

Mitigations from the index — the claim
  • paraphrase-augmented training
  • canonicalization

fmi_5_2_v1 · 5 repeats per case · best context general context · rollups + residuals committed · probe log outside git · manifest hash ties them · method