ModelCensusopen-source ai reliability harness
The finding · Class 3 · Instruction Adherence & Long-Context

Real context moved 80.0pp on Constraint Decay at Depth.

Forgets a rule you set earlier in a long chat.

~intervals overlap — not separated from no change

A constraint set early in a long conversation is silently dropped as the dialogue continues. The rule

openai/gpt-3.5-turbofmi_3_15 repeatsfmi_3_1_v1

loop 2026-09-09 · openai/gpt-3.5-turbo as served · closed weights · released 2023-03 · set s1.4-live · cases v1.7 · 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%25%50%75%100%No context100%[54%100%] n=15 · eff 5Irrelevant context0%presence — a document being there[0%46%] n=15 · eff 5-100.0pp SEPARATEDCurated context80%content — the information itself[36%97%] n=15 · eff 5+80.0pp 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
Hold a formatting rule across 8 unrelated turns.

expected as of 2026-08-09

The rule must survive all 8 turns. Eight turns. The rule has left the recent window for most models.

2Contextchange me

Nothing supplied. The baseline.

3ResponseNo context

No exhibit stored for this context. The full probe log lives outside the repository.

The scoring
Failure rate by context
No context100% [54%100%] n=15 · eff 5
Irrelevant context0% [0%46%] n=15 · eff 5
General context100% [54%100%] n=15 · eff 5
Curated context80% [36%97%] n=15 · eff 5

0–100% · whisker = 95% interval

Trap vs answerable
No contexttrap 100%answerable 100%
Irrelevant contexttrap 0%answerable 0%
General contexttrap 100%answerable 100%
Curated contexttrap 70%answerable 100%

never pooled · a trap ratio would skew the delta

Residual — what survives

100% with no context, 80% under the best supplied source. What survives is 12 failing probes at that best condition, the detector's reason on most of them being: dropped the canary constraint at turn 1.

Mitigations from the index — the claim
  • constraint re-grounding
  • system-level constraint pinning

fmi_3_1_v1 · 5 repeats per case · best context curated context · rollups + residuals committed · probe log outside git · manifest hash ties them · method