# `arts/sess` — Design Consultation Document > **Purpose.** Lay out the design space for `arts/sess` so external reviewers > (humans or AI) can evaluate proposed designs independently. The author has > already iterated several times and proposed multiple incompatible designs; > this document is intentionally neutral about which answer is correct. It > should give you everything needed to form an opinion from first principles. > > **Audience.** Software architects familiar with TypeScript, SvelteKit and > auth/session patterns. Read sections 1–6 for context; sections 7–9 are the > actual decisions to evaluate. --- ## 1. Project context ### What is being built A SvelteKit application at `G:\dev\svelte\active` whose runtime infrastructure lives under `src/arts/`. Each subdirectory is an independent "artifact" (zero-deps, runtime-focused, headless-of-UI). Eight artifacts already exist: | Artifact | Layer(s) | Purpose | | ---------- | ---------------------------------------- | ------------------------------------------------- | | `lang` | `EngineLang`, `ActiveLang`, `MonoLang` | i18n: type-safe translations, BCP 47 resolution | | `logr` | `EngineLogger` | Structured logger: levels, transports, filters | | `fmts` | `EngineFormat`, `ActiveFormat` | Localized formatting: numbers, currency, units, dates | | `sium` | `EngineSium` | Validation contracts (Standard Schema interop) | | `adom` | `ActiveDom` | Reactive DOM service | | `fend` | `ActiveFrontend` | Frontend preferences (theme, mode, dir, density) | | `stor` | `EngineStorage`, `ActiveStorage` | Reactive sync key/value with pluggable adapters | | `http` | `EngineHttp` | HTTP client with retry, schema validation, hooks | | `aapp` | `ActiveApp` | Composition root that wires the rest | A ninth artifact, `arts/sess`, is being designed: **session lifecycle infrastructure on the client**. ### Quality bar The author has stated repeatedly: "professional/impeccable" library quality. Zero deps. Strict types. Comprehensive tests. Production-grade docs. The artifacts will be consumed by many developers. --- ## 2. Established patterns from existing artifacts ### 2.1 `Engine*` vs `Active*` convention - **`Engine*`** — public methods over private state (or no state at all). Pure factory; locale, logger or any volatile input is passed as argument on every call. Lives in `.ts` files, runes-free, safe to import from `+page.server.ts` / `hooks.server.ts`. - **`Active*`** — an `Engine*` that exposes public reactive state. Lives in a `.svelte.ts` file because it owns `$state`. Imports must target the file directly, not the barrel, to keep the rest of the artifact runes-free. ### 2.2 Generic-on-construction patterns Each artifact handles consumer-defined types differently: ```ts // lang: generic on the schema parameter createEngineLang(schema: S): EngineLang // Consumer's S extends LangNode flows through. // stor: generic per entry, NOT per engine const Storage = createActiveStorage(opts); // engine-level, not generic const theme = Storage.entry('theme', 'base'); // generic at entry call // sium: generic at primitive call sites sium.object({ x: sium.string() }) // schema construction is typed; engine is monomorphic // http: generic per request via opt-in schema parameter http.get(url, { schema?: S }) // Returns Out = StandardSchemaV1.InferOutput | unknown ``` ### 2.3 Composition via `createActiveApp` `createActiveApp(options)` builds the runtime members. Every member is **always present** — when not configured, App provides a structurally identical adapter (mono lang, in-memory storage, etc.): ```ts const App = createActiveApp({ lang: { schema, defaultLocale: 'es' }, logger: { level: LogLevel.INFO, transports: [...] }, storage: { adapter: localAdapter }, http: { baseUrl: 'https://api.example.com' } }); App.lang.t(...) App.storage.entry(...) App.http.get(...) ``` ### 2.4 Sium-on-App exception Sium is intentionally **not** a member of App. Validation is page-scoped — pages with forms construct their own engine via a one-line helper: ```ts // In service schema: const App = createActiveApp({ services: { sium: defineEngineSium() } }); // At call site: const sium = App.sium; const result = await sium.validate(LoginSchema, input); ``` The helper takes **zero arguments** because Lang, Logger and the active locale all flow from App. From `feedback_minimal_apis.md`: > When designing helpers on `ActiveApp` that build dependent objects, do NOT > accept an `options` parameter for fields that App already owns. ### 2.5 Auto-wiring between artifacts `createActiveApp` already auto-wires obvious cross-artifact integrations: - Storage diagnostics → shared `Logger` - Lang `setLogger(Logger)` (so DEV warnings flow through Logger) - Format `localeSource` derived from Lang - Frontend `localeSource` shared with Format - Http `logger` → injected automatically - Frontend `persist` → wires through Storage The pattern: pairs of artifacts that always go together get auto-wired. ### 2.6 `arts/stor.entry` precedent (relevant for sess) `arts/stor` is the closest existing precedent for "reactive value container with lifecycle": ```ts interface ActiveStorageEntry { readonly key: string; readonly fullKey: string; /** Reactive — the only public reactive property in the artifact. */ current: T; set(value: T): void; update(fn: (prev: T) => T): void; remove(): void; onChange(fn): () => void; dispose(): void; } ``` Pattern: opaque `T`, single reactive property `current`, plus methods. `Engine*` returns `entry()` instances; `Active*` adds the reactive `current` getter. The engine doesn't know what `T` is. --- ## 3. Memory-encoded constraints These are explicit rules from `.claude/projects/.../memory/*.md`. The author has reaffirmed each multiple times in conversation: ### 3.1 No domain in arts/ From `project_layer_boundaries.md`: > `arts/*` are **runtime infrastructure** — logging, i18n, formatting, > validation contracts, DOM service, frontend preferences, storage, app > composition. Each is independent, runtime-focused, and headless of UI > choices. > Things that **do not** belong in `arts/`: > - Forms (state binding to inputs, generated UI) > - Generated components (buttons, inputs, dialogs) > - **Stores for domain state** (cart, user, session) — Svelte 5 runes in > `.svelte.ts` modules where they belong, not under `App.Stores`. > Rule: when evaluating a new artifact proposal, ask: "could this run > server-side or in a Web Worker?" If no, it belongs above `arts/`. ### 3.2 Minimal API surface From `feedback_minimal_apis.md`: > When designing helpers on `ActiveApp` that build dependent objects, do not > accept an `options` parameter for fields that App already owns. > Reasoning: "si están todos en la App, no tiene porque pasar ningún > parámetro". Adding overrides duplicates what the App already provides as > the single source of truth, invites inconsistency between layers, and > bloats the API surface for cases that don't exist in practice. ### 3.3 Professional design preferences From `feedback_professional_design.md`: > Patterns explicitly rejected during prior artifact builds: > - i18n coupled into the logger > - `minLevel` single cutoff on transports (replaced by `levels` per-severity) > - Runtime arg-shape discrimination (explicit > magical) > - `any` in public types (use `unknown` + type guards or proper unions) > - Directory-name prefixes in external identifiers > - 4-level log hierarchy (upgraded to 6 to match industry standard) ### 3.4 Standard Schema as the validation contract All artifacts that accept user-defined schemas use the Standard Schema v1 interface (`$libs/standard-schema`) so consumers can pass Sium / Zod / Valibot / ArkType interchangeably. **No vendor lock-in.** ### 3.5 `arts/sess` was the topic of prior parking-lot entries From `project_deferred_decisions.md` (current draft): > `arts/sock` (real-time WebSocket / SSE) — parked. Real-time push is a > real gap but deliberately deferred until a concrete consumer surfaces. `arts/cache` (TanStack-Query-style reactive cache) is also parked — a reactive cache with dedup/staleTime/gcTime sits above stor and sess. --- ## 4. Prior art summary What other libraries do, briefly. **Conclusions are intentionally not drawn — they are inputs for the reviewer.** | Library | Storage | Refresh | User | Perms | Cross-tab | Notable | | ---------------- | -------------------- | ------------------------ | ----------------- | ------------------- | ---------------- | -------------------------------------------------------------------- | | **Lucia v3** | Server DB + cookie | Rolling on validate | `userId` (FK) | n/a | implicit | Server-only. `Register` augmentation for session/user attrs. | | **iron-session** | Encrypted cookie | Manual `save()` | Opaque `` | n/a | implicit | 4 KB hard limit. Password rotation supported. | | **Supabase** | Pluggable, default localStorage | Pre-emptive ticker (30s tick, 90s margin) + visibility + 401 | Strongly typed `Session.user` | n/a (server RLS) | `BroadcastChannel` | `_refreshingDeferred` dedup. ~3000 LOC monolith. | | **better-auth** | DB + signed cookie cache | Rolling on getSession | Inferred from server | First-class plugins | None at lib | Cookie chunking (3896 B). Plugin-driven. | | **Auth.js** | DB + JWT | Provider-driven | Module augmentation | None | Cookie-implicit | Provider-coupled (OAuth in scope). | | **Clerk** | Opaque session ID | Pre-emptive | First-class | `session.has(...)` first-class | `BroadcastChannel` | ~75 KB. `addListener` event bus. | Common patterns observable across all: - Refresh dedup via shared promise - Pre-emptive timer + reactive 401 - `INITIAL_SESSION` synchronous on subscribe (Supabase pattern) - Some form of cross-tab broadcast - Visibility-change handling Common divergences: - Whether user identity is in the engine or external - Whether credential shape is named or opaque - Whether permissions are first-class or external - Whether the engine assumes JWT or is auth-scheme-agnostic --- ## 5. Use cases the final design MUST support Any proposed design must handle ALL of the following without mental gymnastics. If a use case requires unusual ceremony, the design has a problem. ### UC-1: JWT/OAuth SPA - Login form returns `{user, accessToken, refreshToken, expiresAt}`. - Auto-refresh fires before expiry. - All HTTP requests carry `Authorization: Bearer `. - 401 from server → refresh → retry the request. ### UC-2: Cookie-based SSR - Server sets `HttpOnly` cookie on login. - Client never sees the credential. - Browser sends cookie automatically with `credentials: 'include'`. - "Logout" hits a server endpoint that clears the cookie. ### UC-3: API-key SaaS dashboard - Long-lived API key stored in localStorage (or generated per-tenant). - No refresh — keys are revoked, not rotated. - All requests carry `X-Api-Key: `. ### UC-4: Anonymous session + later login (e-commerce) - Visitor lands, server starts an anonymous session with a `cartId`. - Visitor adds items to cart without identifying. - Visitor logs in: same session, now with `user` attached, cart preserved. ### UC-5: Multi-tab logout - User has 3 tabs open. - Tab A clicks "Logout". - Tabs B and C reflect the logout (UI shows login prompt) without polling. ### UC-6: SSR hydration without re-validation - `+layout.server.ts` reads cookie, validates session against DB, returns `{user, expiresAt, ...}` to the client via `data`. - Client adopts the snapshot. Schema validation runs ON THE SERVER ONLY — client trusts the SSR boundary. ### UC-7: Concurrent 401s during refresh - 5 in-flight requests all return 401 simultaneously. - ONE refresh fires, the other 4 share its promise. - After refresh, all 5 retry with the new credential. ### UC-8: Refresh failure semantics - Network glitch (transient) → preserve session, retry later. - Server says "refresh token invalid" (fatal) → revoke locally, emit `EXPIRED` event, navigate to `/login`. - Caller must distinguish these without imposing logout-on-flaky-network. ### UC-9: Visibility-change refresh - User closes laptop lid for 90 minutes. - Opens it. Tab becomes visible. - Engine checks expiry, refreshes if needed, before any new request goes out. ### UC-10: Cross-tab WITHOUT exposing tokens via broadcast - Tab A refreshes → broadcast fires → tab B re-reads storage and updates local state. - Broadcast payload contains event + version, NEVER tokens. - An XSS in tab A cannot exfiltrate tokens through the broadcast channel. ### UC-11: Three-state user model (newly raised) The author has stated the design must distinguish: - **No-identificado** (no session OR anonymous session) - **Identificado** (session has a user) - **Autorizado** (session+user+permission for a specific action) These are three conceptually distinct states the design must be able to express clearly. --- ## 6. Decisions LOCKED IN (not up for debate) These came out of audit + iteration cycles and are settled. A proposed design is invalid if it violates any of them. ### 6.1 Refresh contract ```ts type RefreshFn = (current) => Promise; // Resolves to NewSession → engine adopts, fires REFRESHED // Resolves to null → fatal: engine auto-revokes, fires EXPIRED // Throws → transient: engine preserves session, fires REFRESH_FAILED ``` Rationale: distinguishes "credential is dead" from "network is flaky". Mismatch = user logged out by a flaky wifi. ### 6.2 Generation guard The engine maintains a `generation` counter incremented on every adopt/revoke. `refresh()` captures the counter at start and discards the result if the counter changed during the await. Rationale: prevents stale refresh from resurrecting a revoked session when ticker + visibility + 401 hook + manual revoke + cross-tab all coexist. ### 6.3 Refresh dedup Concurrent `refresh()` calls share a single in-flight promise (`refreshingDeferred` slot, Supabase pattern). Rationale: prevents stampede when N requests fail with 401 simultaneously. ### 6.4 `RevokeResult` is tagged ```ts type RevokeResult = | { localRevoked: true; globalRevoked: true; scope: 'global' } | { localRevoked: true; globalRevoked: false; scope: 'local'; reason?: 'missing_revoke_url' | 'network_error' | 'server_rejected' }; ``` `revoke()` is **never** `Promise`. Caller must be able to distinguish "signed out everywhere" from "signed out locally only" — UI copy and security decisions depend on it. ### 6.5 `INITIAL_SESSION` synchronous on subscribe `onChange(listener)` invokes the listener **synchronously once** with `('INITIAL_SESSION', current)` so subscribers are the single source of truth — no race between "read snapshot" and "subscribe". ### 6.6 Broadcast carries event + generation only The `BroadcastChannel` payload is `{type, event, generation}`. NEVER includes tokens, user data, or any sensitive fields. Receiving tabs re-read storage as the source of truth. ### 6.7 `expiresAt` as epoch ms internally Internal storage and broadcast use `number` (epoch ms). Public APIs accept `Date | number | string` and normalize at the boundary. ### 6.8 `adoptServer` is a separate method, not a flag ```ts adopt(input): Promise<...> // validates against schema adoptServer(input): SessionSnapshot // skips validation, normalizes only ``` Rationale: `adopt(snapshot, { trusted: true })` is a footgun (caller might forget the flag); separate method names enforce the distinction. ### 6.9 Auto-refresh wrapper opt-in, not default ```ts withAutoRefresh(engine, { tickMs, marginMs, jitterMs, refreshOnVisible }); ``` - Includes `visibilitychange` handling (battery saver + recovery) - Includes jitter to avoid N-tab stampede - Cleanup function returned ### 6.10 Standard Schema validation (no vendor lock) Any user-supplied schema is `StandardSchemaV1`. Works with Sium, Zod, Valibot, ArkType identically. The artifact only depends on the type interface (~30 LOC in `$libs/standard-schema`). ### 6.11 Out of scope The following are NOT `arts/sess` responsibilities: - OAuth flows (Google, GitHub, etc.) - Password handling / hashing - MFA / TOTP / WebAuthn - JWT signature verification - CSRF protection (delegate to SvelteKit `csrf`) - Server-side session storage (DB, Redis) — separate `arts/sess-server` if needed - Acquisition flow (login form, credential exchange) — consumer territory --- ## 7. OPEN design questions Each question lists 2–4 options with concrete pros/cons. **The reviewer is expected to form an opinion based on the philosophy in §2–3 and the use cases in §5, not on the author's framing.** ### Q1: Session payload generic shape What shape does `SessionSnapshot` take? **Option A — Single opaque payload generic.** ```ts SessionSnapshot = { payload: TPayload; expiresAt: number; issuedAt: number; } ``` - (+) Maximum agnosticism; engine knows nothing about user/credential structure - (+) Mirrors `arts/stor.entry` precedent exactly - (–) Loses semantic structure (can't distinguish identity from credential) - (–) `Sess.current.payload.user.name` is verbose **Option B — User generic + opaque credential.** ```ts SessionSnapshot = { user: TUser | null; // null = anonymous credential?: TCredential; // opaque expiresAt: number; issuedAt: number; } ``` - (+) `user: TUser | null` codifies the unidentified/anonymous/identified state machine - (+) Credential stays opaque (auth-scheme agnostic) - (–) Two generics; potentially over-modeled - (–) Forces consumer to think about user shape upfront **Option C — Three generics: user + credential + claims.** ```ts SessionSnapshot = { user: TUser | null; credential?: TCredential; claims: TClaims; expiresAt: number; issuedAt: number; } ``` - (+) Mirrors Clerk's session.has({permission}) pattern - (–) `TClaims` is authorization concern — does it belong in sess? - (–) Three generics is a lot **Option D — Lucia-style fixed shape with module augmentation.** ```ts SessionSnapshot = { id: string; user: User; // declared via module augmentation expiresAt: number; fresh: boolean; } & SessionAttributes // also from augmentation ``` - (+) Single shape, consumer extends globally - (–) Module augmentation is project-global (one shape per app — fine?) - (–) Doesn't match generic-on-construction patterns elsewhere in `arts/*` ### Q2: Where does "user" live? Strongly correlated with Q1. **Option A — In sess as typed field.** - `Sess.current.user` is the consumer's user object. - Lifecycle of "user" tied to lifecycle of session. **Option B — NOT in sess.** - Sess only knows credential + lifecycle. - Consumer's separate `.svelte.ts` module loads/caches user from `/api/me` on `ADOPTED` event. - Cleanest separation but no engine-level support for "anonymous session with cart" (UC-4) — consumer fully owns the distinction. **Option C — Both (minimal subject + full profile separately).** - Sess has `subject: string | null` (login/email/userId). - Full `User` profile lives in consumer's user store. - "Identified" means `subject !== null`. ### Q3: Where does "credential" live? **Option A — Named `accessToken`/`refreshToken` fields.** - `Sess.current.accessToken`, `Sess.current.refreshToken`. - (+) Trivial bearer header construction; first-class refresh contract - (–) Couples to JWT/OAuth; cookie-only and API-key apps don't fit **Option B — Opaque `credential: TCredential` generic.** - Consumer types it as `{accessToken, refreshToken}` for JWT or `{apiKey}` for API-key auth or `undefined` for cookie auth. - (+) Auth-scheme agnostic - (–) Engine can't auto-construct headers; consumer composes **Option C — Not in sess at all.** - Cookie-only model: server handles credential, client never sees it. - For JWT/API-key, consumer stores credential in their own module. - (–) Loses centralized lifecycle (refresh rotates the credential — needs a writable target) ### Q4: Perms/roles in sess? **Option A — `Sess.has({permission, role})` first-class.** - Typed via `claimsSchema` if provided. - (+) Convenient call site - (–) Authorization is per-action runtime decision, not session state - (–) Forces a permission model on consumers (RBAC vs ABAC vs claims-based) **Option B — Not in sess.** - Consumer module exposes `has(permission)`. - (+) Consumer picks RBAC, ABAC, capability-based, anything - (–) Every consumer reimplements the wheel **Option C — Future `arts/auth` or `$libs/auth` artifact.** - Sess provides primitives; auth artifact provides permission models. - (+) Composable - (–) Doesn't exist yet; speculative ### Q5: How is the session engine constructed? **Option A — Standalone factory, consumer composes with App.** ```ts const Sess = createActiveSession({...}); const App = createActiveApp({ http: { headers: () => bearerHeader(Sess) ?? {} } }); ``` - (+) Sess fully independent of App; testable in isolation - (+) Consumer controls construction order - (–) App can't auto-wire Sess→Http integrations - (–) Awkward closure pattern when `onRefresh` needs `App.http` **Option B — App accepts a pre-built Sess instance.** ```ts const Sess = createActiveSession({...}); const App = createActiveApp({ sess: Sess, http: {...} }); // App.session === Sess; App auto-wires 401 hook ``` - (+) Type flows from Sess to App.session - (+) App can auto-wire what's auto-wireable - (–) Two-step setup - (–) Sess construction can't reference App (circular) **Option C — App constructs Sess from config.** ```ts const App = createActiveApp({ sess: { userSchema: MyUserSchema, ... } }); // App.session = ActiveSession (untyped) OR // ActiveApp (App is now generic on TUser) ``` - (+) Single setup step; matches Lang/Storage/Http pattern - (–) App gains generics for TUser/TCredential — surface bloat - (–) Or App.session is untyped — caller casts everywhere **Option D — App provides factory; consumer calls it.** ```ts const App = createActiveApp({ auth: { // infrastructure config storage: ..., onRefresh: ..., revokeUrl: ... } }); const Sess = App.createActiveSession({ // typed factory userSchema: MyUserSchema }); // App.session === Sess (cached); typed at call site ``` - (+) Mirrors `App.sium` precedent - (+) Infrastructure at App, types at call-site - (+) Type flows correctly via factory generics - (–) Single-call required (second call must throw or replace) - (–) Asymmetry: App constructs Sess but not via App config; uses factory instead ### Q6: Where does configuration live? **Option A — All on call-site of `createActiveSession`.** - userSchema, storage, onRefresh, revokeUrl, autoRefresh — all together - (+) One place to look - (–) Mixes infrastructure (storage) with types (userSchema) **Option B — Split: infra on App, types on call-site.** - App config: storage, onRefresh, revokeUrl, autoRefresh - Call site: userSchema, credentialSchema - (+) Clean separation - (–) Two sources of truth to reconcile **Option C — All on App config; factory takes only generics.** - App config: everything including userSchema - Call site: just `App.createActiveSession()` - (–) Tight coupling between App and consumer types ### Q7: Section name in App config **Option A — `auth: { ... }`** - Consumer-facing semantic name ("I'm configuring authentication"). **Option B — `sess: { ... }`** - Matches the artifact name. **Option C — Both/different name (e.g., `session`, `identity`).** ### Q8: HTTP coupling How tightly does the design couple `arts/sess` to `arts/http`? **Option A — App auto-wires both `headers` and `beforeError` hook.** - Requires sess to expose `bearerHeader()` (assumes JWT/Bearer). - (+) Zero-config for the common case - (–) Wrong for cookie auth, API-key auth, custom schemes **Option B — App auto-wires only `beforeError` hook (refresh is agnostic).** - Consumer composes headers themselves (3 lines). - (+) Auth-scheme agnostic - (–) Consumer must remember to wire bearer if they use it **Option C — No auto-wiring, consumer composes everything.** - (+) Maximum control - (–) Boilerplate at every consumer **Option D — App auto-wires via consumer-provided header builder.** ```ts auth: { bearerHeader: () => Sess.current?.token // consumer provides } // App applies it to App.http.headers ``` ### Q9: User profile loading — where? **Option A — In sess (user is part of session snapshot).** - See Q2 Option A. **Option B — Consumer `.svelte.ts` store (no library helper).** - Consumer subscribes to Sess events, loads user from `/api/me`, caches in `$state`. - ~30 LOC per app. **Option C — `$libs/auth` helper module.** - Provides `createUserStore({ fetcher, cache })`. - (+) Reusable - (–) Duplicates what `arts/cache` (deferred) will provide. **Option D — Defer until `arts/cache` lands.** - User profile is just a query; let consumers wire it manually until cache exists; then promote the pattern. ### Q10: Multi-instance support **Option A — Single `Sess` per app.** - Second `createActiveSession` throws `SessionAlreadyCreatedError`. - (+) Simple - (–) No multi-account UX **Option B — Multiple `Sess` instances allowed.** - Each has its own storage key, refresh, etc. - App.session is the "active" one; can be switched. - (–) Complicates auto-wiring (which Sess does http use?) **Option C — Single Sess, but with internal "scopes".** - (–) Speculative; defer. --- ## 8. Decision dependencies How the questions interact: - **Q1 ↔ Q2 ↔ Q3** — payload shape decides where user/credential live. - **Q5 ↔ Q6** — factory location determines where config lives. - **Q4 ↔ Q9** — permissions and user are both auth-layer concerns; if one is in sess, the other probably should be too (or strictly neither). - **Q3 ↔ Q8** — auto-wiring headers is only possible if credential shape is known to the engine. - **Q5 (Option D) ↔ Q6 (Option B)** — the factory-on-App pattern naturally splits config: App config for infra, factory call for types. - **Q7 ↔ Q5** — section name should match where the config lives. --- ## 9. Cross-AI evaluation framework When evaluating a proposed design, ask: 1. **Does it work for ALL 11 use cases (UC-1 to UC-11)?** If any case requires unusual ceremony, the design has a problem. 2. **Does it respect §3 constraints?** Specifically: no domain in arts/, minimal surface, professional preferences (no `any`, no magical discrimination, opaque generics). 3. **Does it match existing patterns in §2?** Engine/Active split, Standard Schema, opaque generics, auto-wiring conventions, Sium-on-App helper. 4. **Does it survive `arts/cache` landing later?** A design that builds a custom user-store mechanism becomes redundant when cache exists. 5. **Does it work for cookie-only auth (UC-2)** where the client has NO credential? Many auth-tutorial designs assume JWT and break here. 6. **Is the auth-scheme agnosticism real or aspirational?** Test by mentally instantiating UC-1, UC-2, UC-3 and seeing whether the API forces different code paths or scales naturally. 7. **Is the three-state machine (UC-11) expressible without consumer code tracking previous values?** The engine should emit the events that distinguish the transitions. 8. **Can each piece be tested in isolation?** Engine without runes, wrappers without engine, etc. 9. **Is the API surface small?** Count public exports. The author has stated a strong preference for minimal API. --- ## 10. Prior implementation that was rejected A first implementation of `arts/sess` was built and rejected by the author. What it did: - `SessionSnapshot` with `user`, `claims`, `accessToken`, `refreshToken` all as named fields. - `userSchema` and `claimsSchema` required at engine construction. - `bearerHeader()` method on the engine. - `has({permission, role})` method on the engine. - Generics flowed through `App`. - App auto-wired bearer header into `App.http`. Reasons for rejection (in author's own words): > "no entiendo porque session y autentication estan tan acoplados, eso es > una mierda y donde caen todos los sistemas, el diseño es una puta mierda. > deberian de estar en dos modulos separados session a nivel de arts a con > un la informacion de session que no la veo, el usuario deberia de > definirse con un interface minimo, login, name, date start, pero no > acoplado a session y el modulo auth a nivel de libreria" > "se debe de exponer un usuario como generico en session pero la auth no > le corresponde a session y los permisos tampoco, eso corresponde a auth y > el modelo de permisos que se van a propoercionar, al igual que no tiene > sentido el acoplamiento al token porque ya has definido que todo va a ser > por jwt y si quiero otro sistema de autenticacion y autorizacion ?" > "tampoco has tenido en cuenta el estado de un usuario que puede ser > no-identificado | identificado | autorizado" > "la app tiene que propoercionar de crear la session > app.createActiveSession(...), la configuracion de auth debera de > estar definida explicitamente a nivel de la app" Distilled feedback (interpreted, may contain bias): 1. Session and authentication should be separated. 2. User SHOULD be a generic on session, but permissions and authentication should NOT be in session. 3. Don't couple to JWT/Bearer (e.g., named `accessToken` field assumes one auth scheme). 4. The state machine (unidentified | identified | authorized) must be first-class. 5. App should provide the session factory: `App.createActiveSession(...)`. 6. Auth configuration should be explicit at App level. These are interpretive — the reviewer should not assume any one implementation matches the author's intent; instead, evaluate which design options in §7 best satisfy these statements simultaneously. --- ## 11. What the author is asking for A design that: - Resolves the 10 open questions in §7 with explicit reasoning. - Provides TypeScript signatures for the public API (`SessionSnapshot`, `EngineSession`, `ActiveSession`, factories, hooks, events). - Shows the App composition shape (config section + how Sess is built). - Demonstrates how each of the 11 use cases is implemented in 5–10 lines of consumer code. - Identifies any locked-in decisions in §6 that the design forces a change to (and justifies it). - Calls out trade-offs honestly — "I picked X over Y because Z, but acknowledge that Y is better for use case Q". The reviewer should NOT assume any design proposed earlier in the conversation is correct. The author has explicitly stated distrust of the prior design iterations. --- ## Appendix A — Existing artifact code references Key files for context: - `src/arts/aapp/active-app.svelte.ts` — composition pattern - `src/arts/aapp/types.ts` — `ActiveAppOptions` shape - `src/arts/stor/active-storage.svelte.ts` — `entry().current` reactive pattern - `src/arts/stor/types.ts` — `SyncStorageAdapter`, `withBroadcast` interface - `src/arts/http/types.ts` — `HttpResult` tagged union, hook lifecycle - `src/arts/http/engine-http.ts` — `headers: () => ...` lazy hook pattern - `src/arts/sium/engine-sium.ts` — `App.sium` precedent - `src/libs/standard-schema.ts` — Standard Schema v1 type port --- ## Appendix B — Locked-in pieces of the engine implementation These are implementation details from the prior iteration that the author considered correct and would carry over regardless of the high-level design: - Generation guard (counter + capture-then-validate-on-resolve) - `refreshingDeferred` slot for in-flight dedup - `applyExternalChange` helper for cross-tab broadcast receivers (re-reads storage rather than trusting payload) - `validateAndNormalize` helper that runs schemas + normalizes time fields - `commitAdoption` / `commitRevocation` helpers that bump generation and dispatch events atomically - `withAutoRefresh(engine, opts)` as a separate composable wrapper (not baked into the engine) - `extractJwtExp(token)` as opt-in helper in a separate file - `readSessionFromCookies(cookies, opts)` as SSR helper These can be reused regardless of the public API decisions in §7.