Core Concepts

Shard is built around a few key concepts that make it different from other launchers.

The Flow

Profile (manifest) → Content Store (blobs) → Instance (game dir) → Launch

1. Profiles define what you want: Minecraft version, loader, mods
2. The Content Store holds the actual files, deduplicated by hash
3. Instances are materialized game directories, ready to run
4. Launch starts Minecraft with the right arguments

Declarative vs Imperative

Traditional launchers are imperative: you click buttons to install mods, and the launcher modifies state directly. If something breaks, it’s hard to know what changed.

Shard is declarative: your profile is a manifest that describes the desired state. The launcher materializes instances from this manifest. If something breaks, you can inspect the manifest or reset to a known state.

Content-Addressed Storage

Every file in the content store is named by its SHA-256 hash:

~/.shard/store/mods/sha256/a3f2e1d4...

This means:

• No duplicates: Same file = same hash = stored once
• Integrity: If the hash matches, the content is correct
• Easy cleanup: Remove unreferenced blobs safely

Separation of Concerns

Shard separates:

• Profiles: What you want (the manifest)
• Content: What exists (the blobs)
• Instances: What runs (the game dir)
• Minecraft data: Versions, libraries, assets (shared)

This separation makes Shard predictable and scriptable.

Learn More

• Profiles - Deep dive into profile manifests
• Content Store - How deduplication works
• Instances - How game directories are created