Overlap reads and writes real macOS tags (com.apple.metadata:_kMDItemUserTags), so everything stays interoperable with Finder, Spotlight, and other tag tools — nothing is locked in a private database. It works on any file type (images, video, audio, PDFs, text, archives, even folders), not just photos.

Screenshots

Features

• Boolean & Venn queries — tri-state tag chips (include / exclude / off) with All (AND), Any (OR), Exact (only these tags), and multi-diagram Groups ((A OR B) AND C). Paint regions of a Venn diagram to select exact intersections; the diagram is laid out from the real data.
• Saved queries — name and reuse a whole Venn setup (diagrams + excludes).
• Any file type — images, video (inline playback), audio, PDFs, text, archives, and folders. Filter results by kind or extension.
• Live results grid — QuickLook thumbnails (ImageIO fallback for odd files), animated GIFs, adjustable size, multi-select, keyboard navigation.
• Split preview — a large live preview with per-type info (resolution, duration, size, dates) and image EXIF (camera, lens, exposure).
• Slideshow — auto-advancing preview over the results, arrow-key nav, interval + shuffle.
• Fast tagging — quick-tag bar (T, type-ahead), drag-onto-tag, click-to-apply; create / rename / merge / delete tags.
• Queue — watch folders for untagged files, tag them, then Apply to move them into your library. Configurable depth and Finder-style drill-in.
• Tag suggestions — content-based suggestions from a plugin extension point (see Plugins).
• Hidden tags — passcode-gate sensitive tags; per-tag default include/exclude.
• Undo/redo across every mutation (⌘Z / ⌘⇧Z), plus Stats, Fix Extension, Reveal, Export, and drag-out to other apps.

Build

Requires Xcode 15+ (macOS 13+). The project is generated with XcodeGen:

brew install xcodegen
xcodegen generate
open Overlap.xcodeproj      # ⌘R

Overlap runs unsandboxed so it can read and write Finder tags across your folders.

Usage

1. Point it at a folder (toolbar folder button, default ~/Pictures). Spotlight must have indexed the scope for tags to appear.
2. Filter by clicking sidebar tags (cycle include → exclude → off), or paint Venn regions in Explore. Narrow by file Type as needed.
3. Select files, press T, type a tag, ⏎ — tags are written to the files, so Finder and Spotlight see them immediately.
4. Queue: add watched folders, set the subfolder depth, tag the untagged items, then Apply to move them into your library.

Tags live on the files. Deleting a tag in Overlap removes it everywhere — Finder, Spotlight, other tools.

Architecture

• Catalog — an NSMetadataQuery (kMDItemUserTags LIKE '*') finds every tagged item of any type. Metadata is parsed off the main thread and cached to ~/Library/Application Support/Overlap/, so tags appear instantly on the next launch. Firmlink path aliases (/Users vs /System/Volumes/Data/Users) are canonicalized to avoid duplicates.
• One model — TagStore is the single source of truth. The query is a list of VennGroups evaluated as sum-of-products: OR starts a clause, AND binds diagrams within it. Sidebar, chips, Venn, and saved queries all edit this one model.
• Venn layout — deterministic, data-driven geometry (VennLayout.swift): each pair of circles targets a distance from its real overlap, then relaxation + hard constraints settle it. It's SwiftUI-free, so a headless validator (scripts/validate-venn.swift) can replay the exact layout and check every selected region renders.
• Tag I/O — writes go through URLResourceValues.tagNames; every mutation is undoable.

Plugins

Tag suggestions come from an out-of-process plugin system — standalone executables, in any language, discovered at runtime. Overlap pipes a JSON request to a plugin's stdin and reads suggestions from stdout, so suggestion logic (e.g. a future Apple Vision + clustering engine) ships separately from the app.

→ How to write a plugin.

Credits

Inspired by Tagception by Evan Wallace — the project that showed how good a Finder-tag browser can feel.

License

Overlap is free software under the GNU GPL v3.0. You may use, study, share, and modify it; any derivative you distribute must also be open source under the GPL. Free, forever.