Jev vs LLM: a phishing decision benchmark with a calibration audit
A public benchmark comparing Jev with Claude Haiku 4.5 on whether an email agent should click a link, over 2,000 PhishNChips emails, with calibration, latency, cost, and five signal questions.
Both systems saw the same 2,000 PhishNChips v5.2 emails in seeded order, one call per email, no concurrency.
Jev was 62.6% accurate with AUROC 0.689 and ECE 0.154; Claude Haiku 4.5 was 81.3% accurate with AUROC 0.837.
Jev won on cost and speed: $0.038 per 1,000 emails at list price and 239 ms p50 from France versus $0.462 and 687 ms for Haiku.
A cross-validated logistic regression on Jev's five signals reached 95.0% on held-out half B, against 91.8% for a two-feature regex regression.
The signal result was re-controlled after review: Jev's best single signal lost to both the regex (89.4% vs 91.8%) and Haiku asked the same question (94.2%).
Quickstart
bash
cp .env.example .env # fill in the TypeSafe and Anthropic keys
uv run run_jev.py --limit 10 # smoke test, prints raw answers
uv run run_llm.py --limit 10
Watch out
No license file, so reuse terms are unclear. Needs Python 3.13, uv, and both TypeSafe and Anthropic keys; published recall on the dataset varies with the system prompt, and one pass per arm limits stability claims.
Independent cross-model benchmark for Jev-class decision models, running 534 frozen cases per complete entrant with scoring code and a four-axis score of accuracy, calibration, latency and cost.
An experiment comparing Jev with GPT-5.6 Luna, GPT-5.6 Terra, and Claude Sonnet 4.6 as evaluators of five frozen weather-agent runs, measuring pass-or-fail accuracy against human labels plus variance, cost, and latency.
A probability-aware evaluation harness that compares TypeSafe Jev with GLiNER2.5 on zero-shot single-label text classification, measuring calibration, coverage at a fixed error budget, latency, and token cost.
I've been using Jev by @typesafeai Here's the six things i've tried and am confident I'll still use Jev for 60 days from now.
There's many more experiments, ideas, and things I think I will use it for. It's a big deal (more on why in next post).
But I am only sharing thingsShow more
This made me rethink where AI actually fits into security engineering.
For purely engineering work, forget about ChatGPT or Claude.
TypeSafe AI just released Jev, and I think it’s going to change how we build AI into security workflows.
Instead of asking an LLM to “investigateShow more
TypeSafe AI
@typesafeai
we are officially out of stealth! join the frontier and get access to Jev on our website (link on profile)