GUID Warden — Unity Meta & GUID Integrity Guard

Every reference in a Unity project resolves through the GUID in a .meta file. Lose a .meta in a merge, copy a folder with its metas, delete the wrong sidecar - and Unity repairs the damage silently: it mints a fresh GUID, and everything that pointed at the old one goes quietly None. You find out in QA, or on a teammate's machine.

GUID Warden is the guard Unity doesn't ship.

Repairs, with receipts

• Restore a lost .meta from git history - the original GUID, and every reference to it, survives. The one repair Unity itself cannot perform.
• Delete orphaned .meta files with a byte-exact backup and one-click restore.
• Resolve duplicate GUIDs explicitly - you pick which claimant keeps the GUID after seeing every asset that references it. The loser is re-minted with a byte-verified edit, never silently.

Guards, always on

• A background watcher re-scans after every import, off the main thread. Zero per-frame work.
• A dependency-free POSIX-sh pre-commit hook that refuses commits which add an asset without its .meta, delete a .meta whose asset survives, or stage two .meta files with one GUID.
• One-click install of the .gitattributes smart-merge rules and the UnityYAMLMerge driver - scenes and prefabs merge structurally instead of clobbering.
• CI gate: one batch-mode call fails the build on integrity issues. A scan that examined zero files never passes.

Honest by construction

Every act reads its own write back and reports what was verified. Foreign hooks and attributes files are never touched. Refusals are no-ops, stated plainly.

Editor-only (nothing enters your builds), every script in a platform-constrained .asmdef, no Resources folder, all prefs namespaced. Unity 2022.3+ (gated on Unity 6). Full readable C# source with XML docs - MetaScanner, MetaRepair, CollisionResolver, GitHygiene and the CI entry point are public API you can script against.

Proof discipline: compiled warnings-as-errors clean on Unity 6000.5.7f1; 49/49 EditMode tests green, including integration tests against real temporary git repositories. Demo scene and a sandbox seeder included.

The rest of the CSAF Unity toolkit

• Assembly Warden — hand-maintained assembly reference lists are always wrong in one of two directions. This fixes both.
• CoreCLR Migration Scanner — Unity removes Mono in 6.8. Find what breaks before it does.
• Play Compliance — Google stops accepting Android updates without 16 KB page support on 1 Feb 2027.