Alpha support

Install Mosaic on macOS

Last updated August 13, 2026

1. Download and verify

Use the Download for macOS button on this site. The disclosure shows the exact version, architecture, file size, and checksum before opening the immutable GitHub release asset.

For an optional Terminal verification, run the command below from the folder containing the downloaded DMG. The output must match the published SHA-256 exactly.

2. Move Mosaic to Applications

1. Open Mosaic-0.1.0-alpha.1-arm64.dmg.
2. Drag Mosaic into the Applications folder.
3. Eject the Mosaic disk image.

3. Open the unsigned alpha

1. Open Finder and choose Applications.
2. Control-click Mosaic, then choose Open.
3. Review Apple’s warning and choose Open again.

This is Apple’s standard one-app exception for software you explicitly trust. Do not disable Gatekeeper and do not run commands that strip macOS security attributes.

4. Connect Codex

Mosaic needs compatible Codex access for agentic Plan turns. On first launch, Mosaic detects the Codex CLI. If it is missing or you are signed out, the in-app setup wizard can install the compatible user-scoped CLI without administrator access and open browser-based ChatGPT sign-in.

Known alpha limitations

• Plan Studio is the only enabled product workspace.
• Projects, implementation, deployment, Attention, Activity, and provider writes are locked.
• The build is not signed or notarized.
• Windows is not available.
• Keep backups of important Plan exports and generated artifacts.

For version-specific details, read the release notes or inspect the public GitHub release.

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