A semantic grep CLI that chunks files or staged diffs into 5-60 line pieces, packs 16 chunks and 16 Jev Noul questions into one request, and prints file:line hits above a probability threshold with grep-style exit codes.
No index, embeddings, or LLM round-trips: a whole src/ tree searches in about 2 seconds for roughly a cent.
Packs 16 code chunks and 16 Noul questions into one request at $0.042 per million input tokens with output free.
Works on git diffs too, so rules written in English can gate CI; exit status is grep's (0 matched, 1 nothing, 2 error).
--tests selects affected test files in three layers; on a 142-file suite it chose 47 files and 536 cases versus 1,420 in the full run.
Also scores CSV/JSONL rows with Noul, Choice, and Score questions from a JSON file; jgrep init can install a Claude Code or Codex skill.
Quickstart
bash
npm i -g jevgrep
jgrep init
jgrep "catches an error and silently ignores it" src/
jgrep --diff origin/main "adds an HTTP endpoint that has no auth check"
Watch out
MIT-licensed. Needs Node.js and a TypeSafe API key; every chunk's text is sent to TypeSafe's API, chunks are judged in isolation so cross-file questions will not match, and accuracy is lower on non-English text.
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An ast-grep semantic linter where each rule is one natural-language question judged by Jev: 98 rules flag name/body drift, stale comments, weak tests, quiet failures, and commits whose diffs contradict their messages.
A local-first Herdr CLI that filters your agent subscriptions with fixed eligibility rules, then asks TypeSafe Jev to rank the remaining Cursor, Claude Code, Codex, or OpenCode options and pick a reasoning effort.
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)