Crystal compares approaches. Aura decides which one was correct.
Crystal ran several Claude Code and Codex sessions side by side in parallel Git worktrees so you could try two approaches to the same problem and compare them. Stravu deprecated it in February 2026 and continued the idea as Nimbalyst. Aura keeps the part that mattered — parallel attempts in isolated trees — and adds a machine-checked answer to "which of these actually did the job".
What each one is for
What Crystal / Nimbalyst is great at
- Try two ways at once
Running the same task twice and diffing the results is an underrated technique, and Crystal made it a first-class workflow rather than a manual chore.
- Session-shaped, not file-shaped
The unit was a session with its own tree and history, which is closer to how agent work actually behaves.
- A clean desktop app
It was pleasant to use, and the "Integrated Vibe Environment" framing landed before most people had a word for the category.
What Aura adds on top
- An objective comparison
Two attempts, one goal. Aura proves each against the same goal and shows you which paths are wired and which are missing, instead of leaving you to read both diffs.
- A live product
Crystal is deprecated. Aura ships on macOS, Linux and Windows beta every release cycle, and the engine is Apache-2.0.
- Everything after the session
Intent per commit, a deletion guard, cross-branch impact alerts, and a team radar — the layer that matters once more than one person is involved.
Dimension by dimension
Side by side
When to pick which
Pick Crystal / Nimbalyst if…
- You are already on Nimbalyst and it fits how you work.
Pick Aura if…
- You were on Crystal and need somewhere to land that is still shipping.
- Comparing two attempts by eye is not scaling.
- You need Linux or Windows.
Keep Crystal / Nimbalyst. Add the control layer.
Crystal is deprecated, so there is not much to combine. If you are migrating, the import that matters is your repository, and Aura reads that directly — nothing to export.
Aura & Crystal / Nimbalyst
What happened to Crystal?
Stravu deprecated it in February 2026 and continued the work as Nimbalyst. If you are looking for a maintained replacement that runs parallel agent sessions in worktrees, that is the gap Aura fills.
Can Aura run two attempts at the same task?
Yes. Crew can take one goal down two branches and prove each against the same definition of done, so the comparison is a verdict rather than a hunch.
Ship with proof, not hope
Free public beta for macOS and Linux. Point it at a repo and keep driving Crystal / Nimbalyst, now with a semantic diff, a verdict and a record on every change.