Saturn v0.3.1

What's new in 0.3.1

Upgrade if you use 0.3.0 or earlier. This release has a security fix and a crash fix.

• Security: a project's settings files can no longer pre-approve tool calls. The allow rules in a repository's .saturn/settings.json or .claude/settings.json applied without being shown to you, so a cloned repository could let an agent run commands without an approval card. Their deny and ask rules still apply at once; their allow rules now wait until you approve that exact set in Settings → Permissions, and a rule allowing every command is never applied. After upgrading, check the project rules of any repository you opened.
• Fixed: Saturn quitting seconds after launch while indexing a project. The built-in embedding model asked for a single 2 GiB block of memory on large files, which Electron answers by ending the app. It now works in smaller batches and uses a fraction of the memory.
• Fixed: an approval card for a Claude Code or Codex agent could refuse an answer given the moment it appeared.
• The TypeScript SDK moved to its own repository, Saturn-SDK.

Full list in the changelog.

Saturn runs AI agents on your own computer: the agent app, its local runtime and Saturn IDE in one download.

Preview build. The macOS app is not signed with an Apple Developer ID (Apple Silicon only), and the Windows installer is signed with Saturn's self-signed certificate, which Windows does not trust, so both systems warn the first time you open them.

Install

macOS (Apple Silicon)

1. Download Saturn-0.3.1-mac-arm64-unsigned.dmg, open it, and drag Saturn into Applications (the .zip has the same app).
2. Open Saturn. When macOS says it can't verify the developer, go to System Settings → Privacy & Security and click Open Anyway.

Windows (x64)

1. Download Saturn-0.3.1-win-x64-setup.exe and run it.
2. If SmartScreen stops it, click More info → Run anyway. Later versions update themselves.
3. Optional: confirm the installer is Saturn's. In PowerShell, (Get-AuthenticodeSignature .\Saturn-0.3.1-win-x64-setup.exe).SignerCertificate.Thumbprint should print D285DA425077C16A3D115D61F9748AFA574BC786.

Then open Settings → Models, connect a model, create an agent, and give it a task (the first launch walks you through it).

Check a download (optional): each file has a .sha256 beside it, and a signed build attestation that proves it was built from this repository's source by its public release workflow:

shasum -a 256 -c Saturn-0.3.1-mac-arm64-unsigned.dmg.sha256
gh attestation verify Saturn-0.3.1-mac-arm64-unsigned.dmg -R Saturn-Technology-Project/Saturn-App

The signed attestations are attached too (*.sigstore.json); with one, gh attestation verify <file> --bundle <file>.sigstore.json -R Saturn-Technology-Project/Saturn-App checks a download offline.

Saturn-0.3.1-sbom.cdx.json lists every package, model and runtime this release ships (CycloneDX 1.5, with each package's SHA-512), for your scanner or your security team.

Changes

What changed in each version, and whether it affects you, is in CHANGELOG.md.

Full Changelog: v0.3.0...v0.3.1