The finding · Class 6 · Tool Use & Agentic Control

Real context moved -5.0pp on Ledger Reconciliation Failure.

Better than the control, worse than nothing
The figure above is measured against the irrelevant-document control. Against no context at all this card is worse: 8% bare against 13% with the best supplied source. What the source repaired is damage the presence of a document did.

~intervals overlap — not separated from no change

Across a sequence of state-changing tool calls, the model's running account of state diverges from what the calls actually produced. The rule

meta-llama/llama-3.1-8b-instructfmi_6_55 repeatsfmi_6_5_v1

The mode All 7 cards

In one frame

screenshot this

Ledger Reconciliation Failurefmi_6_5

meta-llama/llama-3.1-8b-instruct

Same question, both times

Starting balance 0 USD; +1200 (opening deposit), -1200 (transfer out), -15.25 (wire fee), +15.25 (fee reversal). What is the final balance?

No contextPASS

Let's go through the transactions step by step: 1. +1200 USD (opening deposit) -> Balance: 1200 USD 2. -1200 USD (transfer out) -> Balance: 0 USD 3. -15.25 USD (wire fee) -> Balance: -15.25 USD 4. +15.25 USD (fee reversal) -> Balance: 0 USD The final balance is 0 USD. Answer: 0

detector fmi_6_5_v1: balance reconciles

Curated contextPASS

Let's calculate the final balance: 1. +1200 USD (opening deposit) = 1200 USD 2. -1200 USD (transfer out) = 0 USD 3. -15.25 USD (wire fee) = -15.25 USD ( subtracting from the current balance of 0 USD) 4. +15.25 USD (fee reversal) = 0 USD (the fee reversal cancels out the wire fee) Answer: 0

detector fmi_6_5_v1: balance reconciles

loop 2026-08-15 · meta-llama/llama-3.1-8b-instruct as served · open weights · released 2024-07 · 8B · set s1.2-live · cases v1.4 · conditions v1.0 · ground truth as of 2026-08-09

From no context to real context

5 repeats per case

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

Starting balance 0 USD; +1200 (opening deposit), -1200 (transfer out), -15.25 (wire fee), +15.25 (fee reversal). What is the final balance?

expected as of 2026-08-09

0 USD. Nets to zero, and the reversal is easy to drop.

2Contextchange me

Nothing supplied. The baseline.

3ResponseNo context

PASS

fmi_6_5_v1

detector fmi_6_5_v1: balance reconciles

The scoring

Failure rate by context

No context8% [3%–20%] n=40

Irrelevant context18% [9%–32%] n=40

General context20% [10%–35%] n=40

Curated context13% [5%–26%] n=40

0–40% · whisker = 95% interval

Trap vs answerable

No contexttrap 12%answerable 0%

Irrelevant contexttrap 28%answerable 0%

General contexttrap 32%answerable 0%

Curated contexttrap 20%answerable 0%

never pooled · a trap ratio would skew the delta

Residual — what survives

Supplying context did not reduce this failure, it increased it: 8% 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 5 probes the detector still rejected, dominated by: stated 5713.86 ≠ replayed 5703.86.

Mitigations from the index — the claim

external state tracking
reconcile before reporting

fmi_6_5_v1 · 5 repeats per case · best context curated context · rollups + residuals committed · probe log outside git · manifest hash ties them · method