Jev Guard — Development skill for Claude Code

jev-guard

A Claude Code plugin that scores what the model is about to do — and what it just claimed — with a probability model, and denies the call when the score is high enough.

Conventions written in `CLAUDE.md` are advice. The model follows them until the context gets long, then quietly stops. `jev-guard` moves the ones that matter out of the prompt and into hooks, where a broken rule is a denied tool call with the correction attached, not a review comment three days later.

Scoring runs through [Jev](https://typesafe.ai) (`noul` questions — each returns a probability, not a yes/no), so the thresholds are yours to set. **Every failure path passes the call through**: no key, endpoint down, malformed response, the tool call proceeds. The guard never blocks on the scorer being unavailable.

What it does

**1. Rule guard** (`tool.call` on Edit/Write/Bash)

`hooks/rules.ts` holds two tables. `REGEX_RULES` decide locally — no network, no cost — and suit anything a pattern can settle: a path, a command, a flag. `JEV_RULES` go to Jev as one batched request per tool call and cover what a regex cannot express: *is this a hardcoded color where a token exists?*, *is this a catch block that swallows the error?* A rule's `reason` is shown to the model verbatim, so write it as the correction you want.

**2. Deploy gate** (same request, Bash only)

Two questions on every command: *does this deploy, publish, merge, or send a credential?* and *did the user's last prompt ask for exactly that?* Deny when the first is `≥ denyThreshold` and the second is `< 0.5`. This is what stops an agent from pushing a branch you were still discussing. It is deliberately literal — a general go-ahead does not satisfy the second question, and you will be asked again in the command's own words. That is the design, not a bug.

**3. Background mover** (same request)

A command Jev scores as long-running — installs, a full test suite, a dev server — is rewritten to `run_in_background` instead of b