epicenter

Yjs CRDT patterns, shared types (Y.Map, Y.Array, Y.Text), transactions, y-protocols sync and awareness, y-indexeddb persistence, conflict resolution, and document storage. Use when mentioning Yjs, Y.Doc, CRDTs, collaborative editing, real-time sync, awareness, IndexeddbPersistence, or Yjs providers.

WXT browser extension patterns for entrypoints, background service workers, content scripts, side panels, storage, permissions, host permissions, browser compatibility, and build commands. Use when editing apps/tab-manager, wxt.config.ts, src/entrypoints, extension manifests, or @wxt-dev/storage usage.

House voice for substantial prose: clear, direct, natural, and read-aloud friendly. Use for voice passes, tone work, rewrites, or prose that sounds corporate or AI-shaped.

Reap merged git worktrees and branches safely across the warp, codex, opencode, and conductor harnesses. Use when worktrees pile up, after a branch merges, when cleaning up `git worktree list`, removing an orphaned or detached worktree, or deciding whether a worktree is safe to delete. Not for creating branches or authoring commits (use the git skill).

How a workspace-backed app under `apps/*` is composed: the isomorphic doc factory (`create<App>`), the environment factories (`open<App>Browser` / `open<App>Extension` / tauri) with the one boot call (`connect(toConnection(auth, nodeId))`, ADR-0088/ADR-0094), the `#platform/*` build-time platform DI for multi-platform (Tauri) apps, the workspace singleton, the sign-in migration wiring, daemon/script placement under per-project `workspaces/<app>/`, and the file layout itself. Use when creating a new app, naming or placing the iso/browser/extension factory, wiring `#platform/*` subpath imports for a Tauri seam, placing the workspace singleton, wiring the first-sign-in migration, registering daemon/script bindings, or gating first paint on local storage hydration (load gate vs WorkspaceGate).

Epicenter workspace API patterns: `defineWorkspace`, `defineTable`, `defineKv`, table `.docs(...)`, migrations, actions, `connect(...)`, `mount(...)`, materializers, and lower-level `createWorkspace` / `openCollaboration` primitives. Use when editing workspace schemas, table/KV access, row child docs, actions, runtime connections, daemon mounts, or collaboration setup.

Review UI code for Web Interface Guidelines compliance. Use when asked to "review my UI", "check accessibility", "audit design", "review UX", or "check my site against best practices".

Design, explore, implement, polish, redesign, and review Epicenter interfaces from product direction through component-system collapse. Use when co-designing a screen, asking "what do other apps do", comparing UI directions or comparable apps, turning a rough feature idea into a buildable Svelte surface, choosing @epicenter/ui components, changing packages/ui, or replacing class-heavy markup and local interface primitives. Not for a tiny CSS-only repair unless it reveals a broader pattern.

TypeScript project conventions: derived types, type placement, acronym casing, imports, generics, factories, and runtime schema patterns. Use when editing `.ts` files, defining exported types, reviewing type names, or organizing type tests.

TypeBox patterns for runtime schema validation and JSON Schema generation. Use when mentioning TypeBox, Standard Schema, or schema-based validation.

Make compile-time errors readable by branding constraint-violation types as template literal messages with a U+200B zero-width-space suffix. Use when writing helper functions that constrain object keys, string shapes, or other literal-type inputs and you want the TypeScript error tooltip to read as an English sentence pointing at the offending value.

Turso and libSQL patterns for embedded SQLite-compatible databases, serverless drivers, sync engines, partial sync, WAL/MVCC behavior, compatibility gaps, CLI usage, and Drizzle integration boundaries. Use when mentioning Turso, libSQL, @libsql/client, remote SQLite, embedded replicas, or local database sync.

TypeScript config conventions for this monorepo: the two-base layering, the eight leaf tiers, and the never-redeclare list. Use when adding a package, editing any tsconfig.json, picking a tier for a new app, or debugging module resolution.

Test file conventions: setup functions, factories, Result assertion helpers, organization, type testing, naming, and pruning low-value tests. Use when: "write tests", "add a test", "fix this test", "delete tests", "prune tests", "audit tests", or modifying *.test.ts files.

Technical articles and blog posts with honest trade-offs. Use when: "write a blog post", "draft an article", "write about this", creating articles in docs/articles/.

Tauri commands, permissions, capabilities, security config, path handling, cross-platform file ops, and native filesystem APIs. Use when mentioning Tauri, desktop apps, Rust commands, invoke, capabilities, permissions, ResourceId, file paths, or platform differences.

TanStack Table UI state patterns for @tanstack/svelte-table, @tanstack/table-core, createTable, ColumnDef, FlexRender, renderComponent, sorting, filtering, pagination, row identity, and local table markup composition. Use when building or reviewing Svelte data tables, not Epicenter workspace storage tables.

SVG animation: SMIL, CSS keyframes, stroke path drawing, shape morphing, motion paths. Use when animating an SVG (spinners, animated logos, draw-in effects, morphing icons). Not for static SVG drawing or icon layout.

SvelteKit routing, load functions, server-only modules, form actions, hooks, cookies, env, adapters, and invalidation. Use when editing +page.ts, +page.server.ts, +layout.ts, +server.ts, hooks.server.ts, app.d.ts, or SvelteKit route behavior.

Svelte 5 component and state-module patterns for Epicenter apps. Use when editing `.svelte`, `.svelte.ts`, or Svelte UI state code involving runes, `$props`, snippets, keyed lifecycles, `{#await}`, TanStack Query, `SvelteMap`/`SvelteSet`, `createSubscriber`, `$state.raw`, shadcn-svelte, or workspace observers.

CSS and Tailwind, cn(), flex layouts. Use for "style this", "fix the CSS", "add classes", "not scrolling", "overflow", Tailwind utilities.

Make commits reviewable and auditable as self-contained units, and order multi-file changes into atomic dependency-ordered waves. Use when planning commits, 'split this into commits', 'break this up', 'commit strategy', splitting work into waves, staging changes, reviewing branch history, or deciding whether a commit is too broad, too tiny, incomplete, or hard to revert.

Write technical specs that let agents implement autonomously. Use for "write a spec", "plan this feature", "create a planning doc".

Execute `specs/*.md` plans through working checkpoints. Use when the user says "execute this spec", "implement this plan", "run the spec", or points at a spec file.

Social media post guidelines for LinkedIn, Reddit, Twitter/X. Use when: "post on LinkedIn", "write a tweet", "draft a Reddit post", "share this", drafting announcements.