Parallel Sessions

Run multiple Claude instances on the same repo. Each gets its own branch — no conflicts, no waiting.

Isolated shards use git worktrees to give each Claude agent its own working copy of your repo on a separate branch. Two agents can edit different files at the same time without stepping on each other.

Use split view to watch both agents work side by side in one window. When a shard's work is done, merge it back to main with one click.

Why it matters

Isolated git worktrees

Each isolated shard gets its own branch and working copy. No file conflicts between agents.

Zero-setup workspaces

Crystl detects your package manager, installs dependencies, and symlinks .env files automatically.

Split view

Watch two agents work simultaneously in one window. Compare output in real time.

One-click merge

Rebase onto main, fast-forward merge, and clean up the worktree — all in one click.

Dive deeper in the Isolated Sessions docs

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Frequently asked questions

How many isolated shards can I run at once?
The free plan includes 5 shards per gem. Guild gives you unlimited.
Do isolated shards work with any git repo?
Yes. They use standard git worktrees, so any git repository works.
What happens if two agents edit the same file?
They can't — each isolated shard works on its own branch in its own worktree.
What if my project needs a custom setup step?
Add a setupCommand to .crystl/project.json. Crystl runs it after dependency installation.
What happens to a shard's branch after merging?
Crystl cleans up the worktree and branch automatically after a successful merge.

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