Jev in production › Evaluation and testing

jev-test-filter

CLI sends a git diff to Jev once as shared state with one question per test, then prints filter arguments for vitest, jest, Playwright, cargo test or go test so only affected tests run; one 110-test run cost $0.00098 (author).

Open on GitHub ↗

$0.00098measured, as published by the source
Use
Evaluation and testing
Industry
Developer tools
Form
Open-source tool
Stage
In production
Plugs into
Claude Code
Listed
2026-09-22
Found via
github
Repository
mizchi/jev-test-filter
Stars
35
Forks
2
Last push
2026-10-06
Language
TypeScript
License
MIT

The README opens with

jev-test-filter reads a git diff, asks a model how much that change can alter the outcome of every single test in the repository, and prints the filter arguments your test runner already understands. It hands those arguments to the runner you already use — vitest, jest, node --test, bun test, Playwright, cargo test, go test or rspec — so the run covers the tests the change could plausibly break instead of all of them.

It uses Jev, TypeSafe's System One model: one shared state (the diff), one question per test, one round trip. There is no agent loop and no file reading by the model.

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For the project's own README, linking back here:

Listed in Jev in production

Also used for evaluation and testing