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Benchmark report 02

August 26, 20266 min read

Building confidence on LongMemEval before the full suite

A transparent development timeline on a frozen 12-question diagnostic set, used to improve temporal and knowledge-update memory before spending a full 500-question evaluation.

Key result

75.00%

best fixed-12 diagnostic accuracy

9 of 12 answers were judged correct at the accepted diagnostic checkpoint.

What this result means

This is a development diagnostic, not an official LongMemEval score. We have not run the full 500-question suite. We will do that once retrieval and context compilation are stable enough for a reproducible result.

How we evaluate

We measure the complete system and state the limits of each result.

We evaluate Copepod as a complete system: an answering model working with a durable memory layer. We do not copy another company's architecture or tune our work to match a competitor's reported score. We build the memory system we believe agents need, then measure whether it improves over time.

Quality and efficiency matter together. We report answer and evaluation tokens alongside accuracy because a memory system should improve useful context without relying on an ever larger prompt.

Each published score includes its protocol, category breakdown and limitations. Only complete benchmark runs support headline claims. Smaller tests and retrieval diagnostics remain supporting evidence.

Why this is a diagnostic

We have not run the full 500-question suite. These 12 questions help us check whether the system is ready for a meaningful full evaluation.

Diagnostic history

Results on the fixed 12-question set

All points use the same questions and frozen retrieval input. Each run uses new answer and evaluation calls, so small differences may be random.

50%60%70%80%8/12Run 17/12Run 28/12Run 37/12Run 49/12Run 5
RunOverallTemporalKnowledge updatesTokens / question

Frozen raw top-six control

Control

Raw retrieved sessions supplied without the bounded compiler capsule. This is the fixed diagnostic control, not a product configuration.

8 / 12

66.67%

2 / 6

33.33%

6 / 6

100.00%

21,916

262,995 total

Compiler candidate 23dc6b7

Did not meet the check

Reduced prompt cost substantially, but regressed one answer against the frozen control.

7 / 12

58.33%

3 / 6

50.00%

4 / 6

66.67%

6,424

77,092 total

Compiler candidate ed70543

Did not meet the check

Matched the control overall and improved the temporal slice, but regressed knowledge-update questions.

8 / 12

66.67%

5 / 6

83.33%

3 / 6

50.00%

9,892

118,709 total

Compiler candidate eb1d397

Did not meet the check

Narrowing the fallback evidence did not restore the missing knowledge-update information.

7 / 12

58.33%

4 / 6

66.67%

3 / 6

50.00%

9,806

117,676 total

Temporal-win checkpoint 2b38545

Checkpoint

First accepted diagnostic uplift: one more correct answer than the control, with a much smaller context envelope.

9 / 12

75.00%

4 / 6

66.67%

5 / 6

83.33%

9,726

116,709 total

Scorecard

What we measured and how to read it

75.00% · 9 / 12

Diagnostic accuracy

The best result on the frozen 12-question temporal and knowledge-update diagnostic.

How to use this measure

Use it to decide whether a compiler revision is ready for broader evaluation.

A 12-question diagnostic has high variance and must never be presented as the official 500-question LongMemEval result.

66.67% · 4 / 6

Temporal questions

Questions requiring dates, elapsed time, or changing state in the accepted checkpoint.

How to use this measure

Use it to expose temporal evidence and answer-assembly failures before a full run.

An earlier candidate reached 5/6 temporal but regressed knowledge-update performance, so slices are read together.

83.33% · 5 / 6

Knowledge updates

Questions requiring the system to retain and apply updated information.

How to use this measure

Use it to test whether compressed context preserves superseding facts.

Answer and evaluation model outputs can vary between runs, so a change cannot be attributed to one cause alone.

9,726 tokens / question

Token efficiency

Total answer and judge tokens at the accepted checkpoint, versus 21,916 for the raw top-six control.

How to use this measure

Use it to track whether bounded evidence keeps evaluation cost under control.

Token totals cover this exact 12-question diagnostic protocol and should not be projected directly to production traffic.

Run protocol

Benchmark
LongMemEval fixed diagnostic
Questions scored
12 of the official suite's 500
Retrieval envelope
6 frozen retrieved sessions
Compiler budget
16 facts / 2,400 units
Answering model
GPT-5.6 Luna
Evaluation model
GPT-5.6 Sol
Full-suite status
Not run; awaiting confidence check

What this supports

  • Whether a context-compiler revision deserves a broader evaluation.
  • How temporal and knowledge-update slices trade off within the frozen diagnostic.
  • The token cost of raw retrieved sessions versus bounded compiler capsules.

What this result does not show

  • An official or projected score on the 500-question LongMemEval suite.
  • A leaderboard comparison with systems evaluated on a different denominator or protocol.
  • A causal claim about one compiler change when answer and judge calls were freshly sampled.