The Director

An offline-first tablet app for running tabletop RPG sessions at conventions.

Its permanent feature is the Director Rail — an always-on pacing co-pilot that keeps a hard-clocked slot on time — sitting above a pluggable shell that hosts any game system and any scenario. Built for face-to-face play: no server, no wifi, no install ceremony. Open it on the tablet and it works.

Working name "The Director". Repo gmtool. First deployment: Continuum 2026 — but built as a reusable product for any convention, not one con's materials.

Status

Slice 1 — complete. Proven end-to-end against the AFTERIMAGE pilot scenario:

• <gm-shell> — root: owns the session clock, scenario, beat stamps, and persistence.
• Director Rail — session clock, "you are here" vs target with a live drift badge, next hard trigger countdown, and one-tap "Reached it" stamping (no mental arithmetic mid-scene).
• Dice engine — one seedable core (any die: d4–d100, dF, pools, modifiers) plus pluggable system rule-packs that interpret a roll. Ships with Year-Zero (6–9 = success, 10+ = two).
• Scenario data model — one structured file per scenario; the source of truth (see below).
• Persistence — namespaced localStorage with JSON export/import for backup and device swap.
• Installable PWA — a service worker precaches the shell so it launches offline.

Deferred to later slices: NPC generator, art generator, the rest of the tray tools, more rule-packs and scenarios, and the clue safety-net. See the roadmap below.

Quick start

npm install
npm run dev       # local dev server
npm test          # Vitest suite (jsdom)
npm run build     # static production build → dist/
npm run preview   # serve the production build

Requires Node ≥ 18. No runtime framework — the only dependencies are dev tools (Vite, Vitest, jsdom).

Architecture

Vanilla ES modules and Web Components (light DOM) over a thin core of pure, deterministic logic. All testable logic lives in src/core and src/dice and takes an injected now (ms) or rng (() => [0,1)) — no Date.now() / Math.random() inside — so tests are fully deterministic. Components are dumb renderers that emit events; the shell wires them together.

Unit	Responsibility
src/core/store.js	Namespaced localStorage (gmd.<namespace>.<key>) + export/import
src/core/clock.js	Pure session clock: start / pause / resume / elapsed
src/core/timeline.js	Drift + next-hard-trigger analysis from the scenario timeline
src/core/scenario.js	Scenario validator
src/core/format.js	Elapsed + drift display formatting
src/dice/roller.js	Seedable dice core (pools, modifiers)
src/dice/rulepacks/	System interpreters (year-zero.js) + registry
src/components/director-rail.js	<director-rail> — the always-on pacing bar
src/components/dice-tray.js	<dice-tray> — die picker + roll + verdict
src/components/gm-shell.js	<gm-shell> — root wiring + persistence
src/scenarios/	Scenario data files (afterimage.js)
public/	manifest.webmanifest, sw.js (offline service worker)

Scenario data model

A scenario is one JS module — the single source of truth the Rail reads. The timeline is authored in relative minutes from Start (con slots begin late; relative timing keeps drift honest).

export default {
  meta: { id: 'afterimage', title: 'AFTERIMAGE', system: 'year-zero', players: 4, playMinutes: 210, slot: 'Fri · Slot 2' },
  timeline: [
    // targetMin = minutes after the GM taps Start
    { id: 'a1-open',    label: 'The pier — the case lands', targetMin: 0,   hardTrigger: true },
    { id: 'a1-parlor',  label: 'Parlor 88 interview',       targetMin: 35,  cutHint: 'Summarise the ledger; skip the tea ritual' },
    { id: 'a2-doorcam', label: 'Door-cam reveal',           targetMin: 120, hardTrigger: true },
    // …
  ],
  clues: [], cast: [], props: [],   // reserved for later slices
}

meta.system selects the dice rule-pack. hardTrigger marks immovable beats; cutHint is what to compress if you reach a beat behind schedule.

Roadmap

1. Slice 1 — shell + Director Rail + data model + dice engine (Year-Zero). ✅
2. Slice 2 — NPC generator (offline genre tables) + art generator (offline pencil-art library).
3. Slice 3 — more rule-packs + the remaining convention scenarios.
4. Slice 4 — the clue safety-net (essential-clue gap tracker + fallbacks).
5. Slice 5 — the convention hub (all slots, live "up next / live now").
6. Later — markdown → scenario-data generator; native iPad wrapper.

Docs

• Design: docs/superpowers/specs/2026-07-20-gm-director-design.md
• Slice 1 plan: docs/superpowers/plans/2026-07-20-director-slice1.md

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Personal convention-play tooling. System rule-references paraphrase their respective rulebooks for private table use.