The DM Command Deck

Your Shelf

Every book you own in one binder. Open one to run it — then press Space to summon a table from any of the others, right over the top.

back up your whole binder, or move it to another device

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Adventure Keepers

Packs, Bestiaries & Kits

This shelf only fills up with your books — Gnash is listening for the next one. Get more books → — every Adventure Keeper, bestiary & pack drops straight into the binder.

Under the Hood

"Can this even work?" Yes — with boring, well-supported browser tech. And here's the idea it's built to serve.

The winning formula

⚡ Speed

One gesture. Space, type three letters, any table in your library is on screen. Keyboard-first, because at the table your eyes are on the players, not the menu.

⚖ Zero context-loss

What you summon floats over the open adventure — it never navigates away. Pin a whole board of references; it's saved per adventure and waiting when you return.

📚 One reach

Every book, one shelf. One party that follows you. One dice log for the night. Own more — the whole thing gets richer. Free, offline, yours.

✅

It works. A shell page loads each Keeper in its own isolated frame, indexes their tables into the Summon, and saves everything to the browser's own database. Runs offline at the table. Ships as one downloadable file, or an installable app.

The architecture

Gnasher's Grimoire — the shell (this app)

The Summon

One fuzzy index of every table across every book, built from each Keeper's manifest. The command palette searches it.

The Board + Party + Dice

Floating cards, one roster with portraits, one session roll-log. The DM surface that sits above whatever's running.

Shelf + Switcher

The library. Click a cover, it mounts that Keeper. Swap freely; split two side by side.

▤ Keeper (frame)

Each adventure runs unmodified in its own isolated frame — its own DM tools, dice, secrets intact. Nothing to rebuild.

▤ Keeper B (frame)

A second book loads on demand for split view, sandboxed so scripts never collide.

💾 The Binder (IndexedDB)

Books, boards, party, portraits, roll-log. Export the whole thing as one .keeper file to back up or move devices.

Frames talk to the shell through a tiny message bridge — that's how a table gets pulled out and floated over what's running.

The contract that makes it snap together

Every Keeper is cloned from one engine template. We add one small block to it — a manifest: title, cover, and the book's tables with tags (wilderness, urban, weather, loot…). The Summon reads those manifests. Ship a new book → it appears on the shelf and its tables show up in the Summon automatically. Books already out there get read straight off the page — nothing has to be rebuilt.

The one real wrinkle (and the fix)

⚠ Save data across isolated frames

A book in a sandboxed frame can't always keep its own save reliably. The fix: the shell owns all save data centrally and hands each Keeper its state on open (the engine already has export/import — we just drive it). One binder, one source of truth. The only piece that needs a small touch to the engine template.

Why it's a moat, not just a tool

A PDF dies in a downloads folder. Give away this deck free and every LIDM adventure someone buys snaps into a living thing that gets better the more they own — a deeper Summon, cross-book tables, one party through all of it. It's the DM's second screen, and it only fills up with your books.

About

Free tool. Runs offline; your books stay yours. Get more books at longislanddungeonmaster.com/keepers.

`Space`	Summon — find any table, any book
`R`	Roll the focused card again
`B`	Bookmark this spot — jump back from the bar
`D`	Dice tray
`P`	Party passives strip
`S`	Split — two books side by side
`C`	Combat — muster the fight, run initiative
`Esc`	Close whatever's open