The maintainer confirmed real Fabric and Quilt startup tests on 20 October 2026. The local mod-management workflows below remain separate acceptance checks.
- GitHub Actions Gradle core/desktop tests and build pass.
- Instance-scoped import preserves source and other profiles. Local deterministic suite passes (20 October 2026).
- Enable/disable is a reversible rename with identical SHA-256. Local deterministic suite passes (20 October 2026).
- Removal moves a mod to game/.syntaxlauncher-mod-trash. Local deterministic suite passes (20 October 2026).
- Missing dependencies, duplicate active IDs and disabled dependencies are reported. Local deterministic suite passes (20 October 2026).
- Invalid archives and filename traversal are rejected. Local deterministic suite passes (20 October 2026).
- Create or select a Fabric profile; open Instances → Mods.
- Import a local, trusted Fabric JAR with appropriate Minecraft/loader compatibility.
- Confirm JAR appears under only that instance's game/mods directory.
- Confirm enabling/disabling/removing updates the list, disk and UI without blocking.
- Launch a real Fabric client with the mod and verify it loads.
- Launch Vanilla and a second Fabric profile; neither inherits the first profile's mods.
- Test duplicate filenames, duplicate IDs, missing dependencies, malformed JAR and a mod requiring a newer Fabric loader.
- Try changing mods while the game runs and after detached launcher exit; mutations must be rejected.
- Verify Windows/macOS/Linux dialogs, small displays and file chooser.
Scope: Fabric metadata is advisory only. Version-range evaluation, nested-JAR diagnostics, repository-driven dependency resolution, automatic downloads, update matching and a Forge metadata reader is deferred (Quilt metadata parsing is implemented); do not assume a missing warning implies compatibility. A local JAR can execute arbitrary code once Minecraft loads it, so use trusted sources only.