diff --git a/CHANGELOG.md b/CHANGELOG.md
index 527d526..b18120d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,38 @@
 # Changelog
 
+## 2.0.0
+
+Breaking change — major bump, required by the backend environments release.
+Every project now has exactly two environments, `staging` and `prod`, and the
+SDK key passed as `projectKey` decides which one the player belongs to. The
+environment never appears in the client API: it is resolved at login and
+carried inside the access and refresh tokens. Tokens issued before this
+release have no environment claim and are rejected with 401, so the first call
+after the backend upgrade refreshes, fails, clears the token store and emits
+`'signed-out'` to every `onAuthStateChange` listener. Log the player in again
+with `client.auth.loginWithDevice()` / `loginWithCustom()`.
+
+Quests, scenarios and offers are addressed by their slug instead of their id,
+because ids differ between staging and prod while slugs are stable. Renamed
+accordingly: `Quest.id` is now `Quest.slug`, `client.quests.claim()` takes a
+quest slug, `reportProgress()` resolves to the slugs of the completed quests
+(`ReportQuestProgressResponse.completedQuestSlugs`),
+`client.stores.purchase(storeSlug, offerSlug, options?)` takes an offer slug
+and `OfferHandle` carries a `slug` alongside its `id`,
+`QuestMetrics.purchaseOffer(offerSlug)` builds its metric from the offer slug,
+and every scenario-scoped type exposes `scenarioSlug` instead of `scenarioId` —
+`PendingEffect`, `ScenarioCompletedEffect`, `ScenarioFailedEffect`, the battle
+pass requests and `client.battlePass.getProgress(scenarioSlug, nodeId)`.
+`offer.buy()` is unchanged; it now binds the slug for you. Leaderboards, items
+and stores already used slugs and are untouched.
+
+Also shipped here, previously committed but never published: the effects client
+reconciles against every `GET /sdk/v1/scenarios/pending` response, so a run
+that disappears server-side (finished elsewhere, expired after a promote) now
+emits `onScenarioCompleted` instead of lingering; and `run_not_active` joins
+`unknown_run` and `run_expired` as a terminal rejection that drops the run and
+emits `onScenarioFailed`.
+
 ## 1.0.0
 
 - Scenario execution moved server-side. The SDK no longer walks a local DAG
diff --git a/package-lock.json b/package-lock.json
index 1f84745..911eb24 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@rudder/js-sdk",
-  "version": "1.0.0",
+  "version": "2.0.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@rudder/js-sdk",
-      "version": "1.0.0",
+      "version": "2.0.0",
       "devDependencies": {
         "@types/node": "^26.1.1",
         "jsdom": "^29.1.1",
diff --git a/package.json b/package.json
index fe10785..e17ecd9 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@rudder/js-sdk",
-  "version": "1.0.0",
+  "version": "2.0.0",
   "publishConfig": {
     "registry": "https://hub.rudder.build/api/packages/rudder/npm/"
   },
diff --git a/skills/rudder-web-sdk/SKILL.md b/skills/rudder-web-sdk/SKILL.md
index b4ebf09..e13b3fe 100644
--- a/skills/rudder-web-sdk/SKILL.md
+++ b/skills/rudder-web-sdk/SKILL.md
@@ -74,7 +74,7 @@ service, or standalone economy service in this SDK — wallets live on
 | Player profile + wallets | `client.player` | observable `SyncedState<PlayerProfile>` |
 | Inventory (catalog-merged) | `client.inventory` | observable `SyncedState<InventoryItem[]>` |
 | Catalog | `client.catalog` | observable `SyncedState<Map<string, CatalogItem>>` |
-| Stores / purchases | `client.stores` + `client.stores.purchase(slug, offerId, opts?)` | observable `SyncedState<ShopHandle[]>` |
+| Stores / purchases | `client.stores` + `client.stores.purchase(slug, offerSlug, opts?)` | observable `SyncedState<ShopHandle[]>` |
 | Remote config | `client.remoteConfig` + `.get(key, default?)` | observable, typed |
 | Player storage | `client.storage` + `.save(items)` / `.delete(type)` | observable + mutations |
 | Project storage | `client.projectStorage` + `.save(items)` | observable + mutation |
diff --git a/skills/rudder-web-sdk/reference/auth.md b/skills/rudder-web-sdk/reference/auth.md
index b887a2b..ee3213b 100644
--- a/skills/rudder-web-sdk/reference/auth.md
+++ b/skills/rudder-web-sdk/reference/auth.md
@@ -50,6 +50,19 @@ On success both tokens are saved to the client's `TokenStore`, the runtime
 starts (domains warmed, scenario engine restored, `player_login` event fired),
 and the state flips to `'signed-in'`.
 
+## Environments
+
+A project has two environments, `staging` and `prod`. The SDK key you pass as
+`RudderClientOptions.projectKey` belongs to one of them, so the environment is
+resolved at login and carried inside the access and refresh tokens; nothing in
+the client API takes an environment argument, and a player created in one
+environment is invisible in the other. Content released only to `staging` is
+empty for a `prod` key and vice versa.
+
+Tokens issued before SDK 2.0.0 carry no environment claim and are rejected with
+401. The transport's refresh then fails, clears the token store and emits
+`'signed-out'` — log the player in again.
+
 ## Auth state
 
 ```ts
diff --git a/skills/rudder-web-sdk/reference/battlepass.md b/skills/rudder-web-sdk/reference/battlepass.md
index b9d5224..04ed11d 100644
--- a/skills/rudder-web-sdk/reference/battlepass.md
+++ b/skills/rudder-web-sdk/reference/battlepass.md
@@ -2,7 +2,7 @@
 
 `BattlePassService` (source: `src/battlepass/BattlePassService.ts`).
 Call-and-response access to battle pass endpoints. Battle pass state is tied to
-a **scenario battle pass node**, so calls carry `scenarioId` + `nodeId` (plus
+a **scenario battle pass node**, so calls carry `scenarioSlug` + `nodeId` (plus
 `runId` for mutating calls). NOT observable — re-fetch progress explicitly
 after a mutation.
 
@@ -14,7 +14,7 @@ you already know the scenario/node/run identifiers.
 ## Methods
 
 ```ts
-getProgress(scenarioId: string, nodeId: string): Promise<GetBattlePassProgressResponse>
+getProgress(scenarioSlug: string, nodeId: string): Promise<GetBattlePassProgressResponse>
 addXp(request: AddBattlePassXpRequest): Promise<AddBattlePassXpResponse>
 claimReward(request: ClaimBattlePassRewardRequest): Promise<ClaimBattlePassRewardResponse>
 purchasePremium(request: PurchaseBattlePassPremiumRequest): Promise<PurchaseBattlePassPremiumResponse>
@@ -27,7 +27,7 @@ interface AddBattlePassXpRequest {
   amount?: number;
   nodeId?: string;
   runId?: string;
-  scenarioId?: string;
+  scenarioSlug?: string;
   source?: string;   // configured XP source
 }
 interface AddBattlePassXpResponse {
@@ -41,7 +41,7 @@ interface ClaimBattlePassRewardRequest {
   level?: number;
   nodeId?: string;
   runId?: string;
-  scenarioId?: string;
+  scenarioSlug?: string;
   track?: 'free' | 'premium';
 }
 interface ClaimBattlePassRewardResponse {
@@ -62,7 +62,7 @@ interface PurchaseBattlePassPremiumRequest {
   idempotencyKey?: string;
   nodeId?: string;
   runId?: string;
-  scenarioId?: string;
+  scenarioSlug?: string;
 }
 interface PurchaseBattlePassPremiumResponse {
   error?: string;
@@ -80,5 +80,5 @@ interface PurchaseBattlePassPremiumResponse {
   in the response and the typed error `code` (`RudderErrorCodes`).
 - `purchasePremium` charges the player's wallet; idempotent; pass your own
   `idempotencyKey` for safe retries.
-- Prefer the `onBattlePass` effect session, which binds `scenarioId` /
+- Prefer the `onBattlePass` effect session, which binds `scenarioSlug` /
   `nodeId` / `runId` and posts scenario callbacks for you.
diff --git a/skills/rudder-web-sdk/reference/quests.md b/skills/rudder-web-sdk/reference/quests.md
index 0c309fd..a3af37b 100644
--- a/skills/rudder-web-sdk/reference/quests.md
+++ b/skills/rudder-web-sdk/reference/quests.md
@@ -11,15 +11,15 @@ Distinct from scenario quest nodes, which advance through
 
 ```ts
 list(): Promise<Quest[]>
-claim(questId: string): Promise<ClaimQuestResponse>
-reportProgress(metric: string, amount: number): Promise<string[]>  // ids of quests completed by this report
+claim(questSlug: string): Promise<ClaimQuestResponse>
+reportProgress(metric: string, amount: number): Promise<string[]>  // slugs of quests completed by this report
 ```
 
 ## Types
 
 ```ts
 interface Quest {
-  id?: string;
+  slug?: string;   // stable across environments — what claim() takes
   name?: string;
   objectives?: QuestObjectiveProgress[];
   rewards?: Reward[];
@@ -47,12 +47,12 @@ interface ClaimQuestResponse {
 ```ts
 const quests = await client.quests.list();
 for (const quest of quests) {
-  if (quest.status === 'completed' && quest.id) {
-    const res = await client.quests.claim(quest.id);
+  if (quest.status === 'completed' && quest.slug) {
+    const res = await client.quests.claim(quest.slug);
     // res.success / res.alreadyClaimed / res.granted
   }
 }
-const completedIds = await client.quests.reportProgress('kills', 1);
+const completedSlugs = await client.quests.reportProgress('kills', 1);
 ```
 
 - `claim` is idempotent server-side; check `success` / `alreadyClaimed` /
diff --git a/skills/rudder-web-sdk/reference/scenarios.md b/skills/rudder-web-sdk/reference/scenarios.md
index a41d9fb..fc6c24c 100644
--- a/skills/rudder-web-sdk/reference/scenarios.md
+++ b/skills/rudder-web-sdk/reference/scenarios.md
@@ -122,7 +122,7 @@ counter response may carry the next `PendingEffect`.
 }
 ```
 
-These wrap `client.battlePass` with the run's `scenarioId`/`nodeId`/`runId`
+These wrap `client.battlePass` with the run's `scenarioSlug`/`nodeId`/`runId`
 already bound — prefer them over calling the service manually.
 
 ### `BattlePassLevelEffect` — a `battlepass_level` node (single claimable tier)
@@ -134,9 +134,9 @@ already bound — prefer them over calling the service manually.
 ### Run lifecycle effects
 
 ```ts
-interface ScenarioCompletedEffect { readonly runId: string; readonly scenarioId: string }
+interface ScenarioCompletedEffect { readonly runId: string; readonly scenarioSlug: string }
 interface ScenarioFailedEffect {
-  readonly runId: string; readonly scenarioId: string; readonly nodeId: string;
+  readonly runId: string; readonly scenarioSlug: string; readonly nodeId: string;
   readonly error: Error;
 }
 ```
@@ -154,7 +154,7 @@ not delivered to the client.
 ## Reliability notes
 
 - Completion methods POST `/sdk/v1/scenarios/callback` with
-  `{scenarioId, runId, nodeId, handle}` using the handles `output`,
+  `{scenarioSlug, runId, nodeId, handle}` using the handles `output`,
   `onPurchase`, `onDecline`, `onEnd`, `onClaim`, `onComplete`, `onLevelUp`,
   `onPremiumPurchase`.
 - Transient callback failures (network error, 5xx) leave the effect active
diff --git a/skills/rudder-web-sdk/reference/stores.md b/skills/rudder-web-sdk/reference/stores.md
index c427153..cf47d0b 100644
--- a/skills/rudder-web-sdk/reference/stores.md
+++ b/skills/rudder-web-sdk/reference/stores.md
@@ -13,7 +13,7 @@ client.stores.onChange(cb);
 await client.stores.load() / .reload();
 
 // Direct purchase (bypassing handles):
-await client.stores.purchase(storeSlug, offerId, options?);
+await client.stores.purchase(storeSlug, offerSlug, options?);
 ```
 
 ## Handles
@@ -28,7 +28,8 @@ class ShopHandle {
 }
 
 class OfferHandle {
-  readonly id: string;
+  readonly id: string;    // authoring id, differs between staging and prod
+  readonly slug: string;  // stable across environments — what purchases use
   readonly name?: string;
   readonly price?: OfferPrice;        // { amount?: number; currency?: string }
   readonly contents: OfferContent[];  // { amount?: number; itemId?: string }[]
@@ -48,15 +49,15 @@ interface PurchaseOfferResponse {
 
 ## Purchase semantics
 
-- `stores.purchase(storeSlug, offerId, options?)` and `offer.buy(options?)` are
-  the same executor; handles just bind the slug/id.
+- `stores.purchase(storeSlug, offerSlug, options?)` and `offer.buy(options?)` are
+  the same executor; handles just bind the store slug and the offer slug.
 - When `options.idempotencyKey` is omitted the SDK generates
   `crypto.randomUUID()` per call — safe retries require passing your own key.
 - On success the executor invalidates `player`, `inventory`, and `stores`, so
   subscribers observe fresh wallet/inventory/store data immediately.
 - Check `response.success` / `response.error` — a failed purchase is a resolved
   response, not necessarily a thrown error.
-- Purchase metrics (`purchase.offer:<offerId>`, `purchase.item:<itemId>`) are
+- Purchase metrics (`purchase.offer:<offerSlug>`, `purchase.item:<itemId>`) are
   reported to quests automatically server-side — do not report them manually
   (see `reference/quests.md`).
 
@@ -71,10 +72,11 @@ interface Store {
 }
 interface Offer {
   contents?: OfferContent[]; createdAt?: string; id?: string;
-  maxPurchases?: number; name?: string; price?: OfferPrice; updatedAt?: string;
+  maxPurchases?: number; name?: string; price?: OfferPrice; slug?: string;
+  updatedAt?: string;
 }
 ```
 
 `ShopHandle`/`OfferHandle` throw a plain `Error` if constructed from a store
-without `slug` / an offer without `id` — in practice the domain only builds
-handles from server data that has both.
+without `slug` / an offer without `id` or `slug` — in practice the domain only
+builds handles from server data that has all of them.