PAIRED MODEL EVALUATION / 2026-09-26

A bounded
decision engine.

Choose a tool, retain a trajectory, or check one piece of evidence. The fixed requests and both answers are available for inspection.

KEV-4B / PINNED RELEASEJEV 1.13.0 / FRESH RUN14 COMPLETE RUNS

[ REPORT / 01 ]

Five tasks inside an agent.

These small, hand-authored tasks isolate a decision that a larger agent could delegate: choosing a tool, selecting a complete trajectory, checking relevance, checking completion, or choosing files. Correct labels follow the written request and evidence. They do not establish production agent reliability.

DecisionKev resultJev resultKev recallJev recallRequests
Choose one of 15 tools100.0%100.0%n/an/a40
Keep one of four trajectories100.0%100.0%n/an/a24
Judge tool-result relevance0.95 F10.85 F1100.0%100.0%40
Check subgoal completion0.98 F11.00 F1100.0%100.0%40
Select files for context0.85 F10.67 F194.4%94.4%225

The fixtures were published in the earlier report. Model training overlap was not audited. High scores here therefore cannot establish generalization to unseen production traces.

[ REPORT / 02 ]

Inspect the errors,
not just the average.

File-context selection has 18 relevant files among 225 judgments. Rejecting every file would score 92% accuracy while recovering no relevant context. Positive F1, recall, false positives, and false negatives therefore matter more than the combined accuracy across all tasks.

DecisionModelTrue positiveFalse positiveFalse negativeTrue negativeBrier
Judge tool-result relevanceKEV2020180.0520
Judge tool-result relevanceJEV2070130.1092
Check subgoal completionKEV2010190.0220
Check subgoal completionJEV2000200.0065
Select files for contextKEV17512020.0529
Select files for contextJEV171611910.0641

A false positive keeps an irrelevant result, claims an incomplete subgoal is complete, or adds an irrelevant file. A false negative discards useful evidence or misses a completed subgoal. Brier measures probability error; lower is better. It uses the returned yes probability and the original 0.5 decision threshold.

[ REPORT / 03 ]

Timing and paired variations.

DecisionKev p50Jev p50Kev p95Jev p95
Choose one of 15 tools37.33 ms125.80 ms89.95 ms272.16 ms
Keep one of four trajectories32.37 ms124.31 ms33.53 ms171.91 ms
Judge tool-result relevance31.12 ms124.75 ms83.71 ms173.07 ms
Check subgoal completion31.10 ms132.31 ms31.91 ms173.93 ms
Select files for context30.97 ms128.16 ms31.30 ms179.56 ms

For 72 related pairs, changes in option order or incidental wording preserved the semantic answer in 71/72 Kev pairs and 71/72 Jev pairs. For trajectory choices, semantic agreement compares the selected text after option reordering, not the option key.

The 72 pairs are related copies of 72 base tasks, not 144 independent observations. The 225 file judgments are grouped into 15 search tasks. Client timing includes local versus hosted network paths.

[ REPORT / 04 ]

Support tickets,
then the same tickets again.

The original 40 ticket requests and four fixed team descriptions were sent serially to both models in the same fixed order, first as new states and then as an exact replay. The replay uses no client answer cache. Server caches may apply; Kev retains only four state prefixes by default, so cycling through 40 states is not the same cache condition as CLM's earlier replay.

ConditionModelCorrectAccuracyClient p50Client p95
New statesKEV40/40100.0%31.83 ms82.46 ms
New statesJEV40/40100.0%122.14 ms168.36 ms
Exact replayKEV40/40100.0%31.42 ms83.16 ms
Exact replayJEV40/40100.0%124.02 ms220.62 ms

[ REPORT / 05 ]

Inspect every narrow decision.

Loading frozen results...

[ REPORT / 06 ]

Historical CLM reference.

These CLM results are from September 24 and were not rerun for this report. The builder verifies that the narrow-decision request hash is identical. The comparison can show how the models answered the same fixture; historical timing remains tied to the original serving stack.

DecisionHistorical CLMNew KevNew Jev
Choose one of 15 tools50.0%100.0%100.0%
Keep one of four trajectories58.3%100.0%100.0%
Judge tool-result relevance0.18 F10.95 F10.85 F1
Check subgoal completion0.57 F10.98 F11.00 F1
Select files for context0.36 F10.85 F10.67 F1