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Large Language ModelsAI Coding AssistantsZenn AI/MLPublished: Oct 21, 2026, 13:00 JST

Jev tuned 6 times, still loses to Claude (Opus) grep by 2x

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Jev tuned 6 times, still loses to Claude (Opus) grep by 2x

3 Key Points

  1. What happened

    After six rounds of tuning TypeSafe AI's Jev for note selection, the author benchmarked it on 100 requests against Claude (Opus) using grep; Opus got 52 of 77 note-requiring requests right, Jev 24.

  2. Why it matters

    Even a model that reached 0% wrong proposals in a 20-request test collapsed to 20% wrong on 100 requests, so tuning gains measured on small samples may not hold.

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Context & Analysis

The author's starting point was a hook that injected excerpts of Obsidian notes into every Claude Code request. Over the most recent 14 days it fired 2,333 times, averaging 4,840 characters per insertion, yet Claude read only 0.9% of the vault on its own and just 3 of 154 notes it read had been among the hook's candidates. That made context selection the problem to solve, and Jev — a model that returns typed judgments and probabilities instead of text — looked like a cheap, fast classifier for the job.

The tuning history shows why the final comparison mattered. Early attempts asked for yes/no on hundreds of candidates and missed 46% of the time. A version that classified only the request text was fast but caught the right domain just 55% of the time. The third round, using a choice over all candidates plus recent conversation, produced a 0% wrong-proposal rate on 20 requests — a result the author later called too good, since the threshold was picked on the same 20. When the test grew to 100 requests and 1,331 candidates, that method's error rate rose to 40%.

Against that backdrop, the Opus grep baseline was never measured until the author asked for it. On the same 100 requests, Opus with grep and conversation context found 52 correct notes versus Jev's 24, and combining the two only moved the count from 52 to 54. Jev did have a lower wrong-proposal rate (20% versus 25% for Opus's top pick) and fewer false proposals on requests needing no note. The author's conclusion is that Jev fits narrow, high-volume classification or gating tasks, while a context-aware model already in the conversation is hard to beat on note selection.

FAQ
How did the author measure whether a selected note was correct?
Selected notes were passed to a separate LLM agent to judge relevance, without revealing which method chose them, and the author notes not every case was checked by a human.
What did the author change in their workflow after the comparison?
They removed the hook that injected context on every request and added one line to their global CLAUDE.md telling Claude to grep the index and read only needed notes before answering.
When would Jev be the better choice?
When the answer choices are small and fixed, all the judgment material is in a short input, no context-aware smart model is present, and volume or per-item speed matters.
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