fix(backend): handle remove() during in-flight session creation

Cancel pending getOrCreate when remove() is called mid-flight.
Destroy the resulting session to prevent it from leaking.

Co-authored-by: Ona <no-reply@ona.com>

.github/workflows/build-waitlist-website.yml

@@ -0,0 +1,42 @@
+name: Build waitlist website
+
+on:
+  push:
+    branches: [master]
+    paths:
+      - apps/waitlist-website/**
+      - .github/workflows/build-waitlist-website.yml
+
+  workflow_dispatch:
+
+env:
+  REGISTRY: cr.nym.sh
+  IMAGE_NAME: aelis-waitlist-website
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Log in to container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ secrets.REGISTRY_USERNAME }}
+          password: ${{ secrets.REGISTRY_PASSWORD }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: apps/waitlist-website
+          push: true
+          tags: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ github.sha }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max

.github/workflows/test.yml

@@ -21,4 +21,4 @@ jobs:
         run: bun install --frozen-lockfile
 
       - name: Run tests
-        run: bun test
+        run: bun run test

apps/aelis-backend/src/engine/http.test.ts

@@ -1,7 +1,7 @@
 import type { ActionDefinition, ContextEntry, FeedItem, FeedSource } from "@aelis/core"
 
 import { contextKey } from "@aelis/core"
-import { describe, expect, test } from "bun:test"
+import { describe, expect, spyOn, test } from "bun:test"
 import { Hono } from "hono"
 
 import { mockAuthSessionMiddleware } from "../auth/session-middleware.ts"
@@ -64,6 +64,7 @@ describe("GET /api/feed", () => {
 		const items: FeedItem[] = [
 			{
 				id: "item-1",
+				sourceId: "test",
 				type: "test",
 				priority: 0.8,
 				timestamp: new Date("2025-01-01T00:00:00.000Z"),
@@ -71,12 +72,12 @@ describe("GET /api/feed", () => {
 			},
 		]
 		const manager = new UserSessionManager({
-			providers: [() => createStubSource("test", items)],
+			providers: [async () => createStubSource("test", items)],
 		})
 		const app = buildTestApp(manager, "user-1")
 
 		// Prime the cache
-		const session = manager.getOrCreate("user-1")
+		const session = await manager.getOrCreate("user-1")
 		await session.engine.refresh()
 		expect(session.engine.lastFeed()).not.toBeNull()
 
@@ -96,6 +97,7 @@ describe("GET /api/feed", () => {
 		const items: FeedItem[] = [
 			{
 				id: "fresh-1",
+				sourceId: "test",
 				type: "test",
 				priority: 0.5,
 				timestamp: new Date("2025-06-01T12:00:00.000Z"),
@@ -103,7 +105,7 @@ describe("GET /api/feed", () => {
 			},
 		]
 		const manager = new UserSessionManager({
-			providers: [() => createStubSource("test", items)],
+			providers: [async () => createStubSource("test", items)],
 		})
 		const app = buildTestApp(manager, "user-1")
 
@@ -134,7 +136,7 @@ describe("GET /api/feed", () => {
 				throw new Error("connection timeout")
 			},
 		}
-		const manager = new UserSessionManager({ providers: [() => failingSource] })
+		const manager = new UserSessionManager({ providers: [async () => failingSource] })
 		const app = buildTestApp(manager, "user-1")
 
 		const res = await app.request("/api/feed")
@@ -146,6 +148,27 @@ describe("GET /api/feed", () => {
 		expect(body.errors[0]!.sourceId).toBe("failing")
 		expect(body.errors[0]!.error).toBe("connection timeout")
 	})
+
+	test("returns 503 when all providers fail", async () => {
+		const manager = new UserSessionManager({
+			providers: [
+				async () => {
+					throw new Error("provider down")
+				},
+			],
+		})
+		const app = buildTestApp(manager, "user-1")
+
+		const spy = spyOn(console, "error").mockImplementation(() => {})
+
+		const res = await app.request("/api/feed")
+
+		expect(res.status).toBe(503)
+		const body = (await res.json()) as { error: string }
+		expect(body.error).toBe("Service unavailable")
+
+		spy.mockRestore()
+	})
 })
 
 describe("GET /api/context", () => {
@@ -156,12 +179,12 @@ describe("GET /api/context", () => {
 	// The mock auth middleware always injects this hardcoded user ID
 	const mockUserId = "k7Gx2mPqRvNwYs9TdLfA4bHcJeUo1iZn"
 
-	function buildContextApp(userId?: string) {
+	async function buildContextApp(userId?: string) {
 		const manager = new UserSessionManager({
-			providers: [() => createStubSource("weather", [], contextEntries)],
+			providers: [async () => createStubSource("weather", [], contextEntries)],
 		})
 		const app = buildTestApp(manager, userId)
-		const session = manager.getOrCreate(mockUserId)
+		const session = await manager.getOrCreate(mockUserId)
 		return { app, session }
 	}
 
@@ -175,7 +198,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns 400 when key param is missing", async () => {
-		const { app } = buildContextApp("user-1")
+		const { app } = await buildContextApp("user-1")
 
 		const res = await app.request("/api/context")
 
@@ -185,7 +208,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns 400 when key is invalid JSON", async () => {
-		const { app } = buildContextApp("user-1")
+		const { app } = await buildContextApp("user-1")
 
 		const res = await app.request("/api/context?key=notjson")
 
@@ -195,7 +218,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns 400 when key is not an array", async () => {
-		const { app } = buildContextApp("user-1")
+		const { app } = await buildContextApp("user-1")
 
 		const res = await app.request('/api/context?key="string"')
 
@@ -205,7 +228,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns 400 when key contains invalid element types", async () => {
-		const { app } = buildContextApp("user-1")
+		const { app } = await buildContextApp("user-1")
 
 		const res = await app.request("/api/context?key=[true,null,[1,2]]")
 
@@ -215,7 +238,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns 400 when key is an empty array", async () => {
-		const { app } = buildContextApp("user-1")
+		const { app } = await buildContextApp("user-1")
 
 		const res = await app.request("/api/context?key=[]")
 
@@ -225,7 +248,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns 400 when match param is invalid", async () => {
-		const { app } = buildContextApp("user-1")
+		const { app } = await buildContextApp("user-1")
 
 		const res = await app.request('/api/context?key=["aelis.weather"]&match=invalid')
 
@@ -235,7 +258,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns exact match with match=exact", async () => {
-		const { app, session } = buildContextApp("user-1")
+		const { app, session } = await buildContextApp("user-1")
 		await session.engine.refresh()
 
 		const res = await app.request('/api/context?key=["aelis.weather","weather"]&match=exact')
@@ -247,7 +270,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns 404 with match=exact when only prefix would match", async () => {
-		const { app, session } = buildContextApp("user-1")
+		const { app, session } = await buildContextApp("user-1")
 		await session.engine.refresh()
 
 		const res = await app.request('/api/context?key=["aelis.weather"]&match=exact')
@@ -256,7 +279,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns prefix match with match=prefix", async () => {
-		const { app, session } = buildContextApp("user-1")
+		const { app, session } = await buildContextApp("user-1")
 		await session.engine.refresh()
 
 		const res = await app.request('/api/context?key=["aelis.weather"]&match=prefix')
@@ -273,7 +296,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("default mode returns exact match when available", async () => {
-		const { app, session } = buildContextApp("user-1")
+		const { app, session } = await buildContextApp("user-1")
 		await session.engine.refresh()
 
 		const res = await app.request('/api/context?key=["aelis.weather","weather"]')
@@ -285,7 +308,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("default mode falls back to prefix when no exact match", async () => {
-		const { app, session } = buildContextApp("user-1")
+		const { app, session } = await buildContextApp("user-1")
 		await session.engine.refresh()
 
 		const res = await app.request('/api/context?key=["aelis.weather"]')
@@ -301,7 +324,7 @@ describe("GET /api/context", () => {
 	})
 
 	test("returns 404 when neither exact nor prefix matches", async () => {
-		const { app, session } = buildContextApp("user-1")
+		const { app, session } = await buildContextApp("user-1")
 		await session.engine.refresh()
 
 		const res = await app.request('/api/context?key=["nonexistent"]')

apps/aelis-backend/src/engine/http.ts

@@ -33,7 +33,14 @@ export function registerFeedHttpHandlers(
 async function handleGetFeed(c: Context<Env>) {
 	const user = c.get("user")!
 	const sessionManager = c.get("sessionManager")
-	const session = sessionManager.getOrCreate(user.id)
+
+	let session
+	try {
+		session = await sessionManager.getOrCreate(user.id)
+	} catch (err) {
+		console.error("[handleGetFeed] Failed to create session:", err)
+		return c.json({ error: "Service unavailable" }, 503)
+	}
 
 	const feed = await session.feed()
 
@@ -46,7 +53,7 @@ async function handleGetFeed(c: Context<Env>) {
 	})
 }
 
-function handleGetContext(c: Context<Env>) {
+async function handleGetContext(c: Context<Env>) {
 	const keyParam = c.req.query("key")
 	if (!keyParam) {
 		return c.json({ error: 'Invalid or missing "key" parameter: must be a JSON array' }, 400)
@@ -70,7 +77,15 @@ function handleGetContext(c: Context<Env>) {
 
 	const user = c.get("user")!
 	const sessionManager = c.get("sessionManager")
-	const session = sessionManager.getOrCreate(user.id)
+
+	let session
+	try {
+		session = await sessionManager.getOrCreate(user.id)
+	} catch (err) {
+		console.error("[handleGetContext] Failed to create session:", err)
+		return c.json({ error: "Service unavailable" }, 503)
+	}
+
 	const context = session.engine.currentContext()
 	const key = contextKey(...parsed)
 

apps/aelis-backend/src/enhancement/merge.test.ts

@@ -9,6 +9,7 @@ import { mergeEnhancement } from "./merge.ts"
 function makeItem(overrides: Partial<FeedItem> = {}): FeedItem {
 	return {
 		id: "item-1",
+		sourceId: "test",
 		type: "test",
 		timestamp: new Date("2025-01-01T00:00:00Z"),
 		data: { value: 42 },

apps/aelis-backend/src/enhancement/merge.ts

@@ -2,6 +2,8 @@ import type { FeedItem } from "@aelis/core"
 
 import type { EnhancementResult } from "./schema.ts"
 
+const ENHANCEMENT_SOURCE_ID = "aelis.enhancement"
+
 /**
  * Merges an EnhancementResult into feed items.
  *
@@ -10,7 +12,11 @@ import type { EnhancementResult } from "./schema.ts"
  * - Returns a new array (no mutation)
  * - Ignores fills for items/slots that don't exist
  */
-export function mergeEnhancement(items: FeedItem[], result: EnhancementResult, currentTime: Date): FeedItem[] {
+export function mergeEnhancement(
+	items: FeedItem[],
+	result: EnhancementResult,
+	currentTime: Date,
+): FeedItem[] {
 	const merged = items.map((item) => {
 		const fills = result.slotFills[item.id]
 		if (!fills || !item.slots) return item
@@ -31,6 +37,7 @@ export function mergeEnhancement(items: FeedItem[], result: EnhancementResult, c
 	for (const synthetic of result.syntheticItems) {
 		merged.push({
 			id: synthetic.id,
+			sourceId: ENHANCEMENT_SOURCE_ID,
 			type: synthetic.type,
 			timestamp: currentTime,
 			data: { text: synthetic.text },

apps/aelis-backend/src/enhancement/prompt-builder.test.ts

@@ -7,6 +7,7 @@ import { buildPrompt, hasUnfilledSlots } from "./prompt-builder.ts"
 function makeItem(overrides: Partial<FeedItem> = {}): FeedItem {
 	return {
 		id: "item-1",
+		sourceId: "test",
 		type: "test",
 		timestamp: new Date("2025-01-01T00:00:00Z"),
 		data: { value: 42 },
@@ -60,7 +61,9 @@ describe("buildPrompt", () => {
 
 		expect(parsed.items).toHaveLength(1)
 		expect((parsed.items as Array<Record<string, unknown>>)[0]!.id).toBe("item-1")
-		expect((parsed.items as Array<Record<string, unknown>>)[0]!.slots).toEqual({ insight: "Weather insight" })
+		expect((parsed.items as Array<Record<string, unknown>>)[0]!.slots).toEqual({
+			insight: "Weather insight",
+		})
 		expect((parsed.items as Array<Record<string, unknown>>)[0]!.type).toBeUndefined()
 		expect(parsed.context).toHaveLength(0)
 	})

apps/aelis-backend/src/location/http.ts

@@ -44,7 +44,15 @@ async function handleUpdateLocation(c: Context<Env>) {
 
 	const user = c.get("user")!
 	const sessionManager = c.get("sessionManager")
-	const session = sessionManager.getOrCreate(user.id)
+
+	let session
+	try {
+		session = await sessionManager.getOrCreate(user.id)
+	} catch (err) {
+		console.error("[handleUpdateLocation] Failed to create session:", err)
+		return c.json({ error: "Service unavailable" }, 503)
+	}
+
 	await session.engine.executeAction("aelis.location", "update-location", {
 		lat: result.lat,
 		lng: result.lng,

apps/aelis-backend/src/server.ts

@@ -3,9 +3,9 @@ import { Hono } from "hono"
 
 import { registerAuthHandlers } from "./auth/http.ts"
 import { mockAuthSessionMiddleware, requireSession } from "./auth/session-middleware.ts"
+import { registerFeedHttpHandlers } from "./engine/http.ts"
 import { createFeedEnhancer } from "./enhancement/enhance-feed.ts"
 import { createLlmClient } from "./enhancement/llm-client.ts"
-import { registerFeedHttpHandlers } from "./engine/http.ts"
 import { registerLocationHttpHandlers } from "./location/http.ts"
 import { UserSessionManager } from "./session/index.ts"
 import { WeatherSourceProvider } from "./weather/provider.ts"
@@ -26,7 +26,7 @@ function main() {
 
 	const sessionManager = new UserSessionManager({
 		providers: [
-			() => new LocationSource(),
+			async () => new LocationSource(),
 			new WeatherSourceProvider({
 				credentials: {
 					privateKey: process.env.WEATHERKIT_PRIVATE_KEY!,

apps/aelis-backend/src/session/feed-source-provider.ts

@@ -1,9 +1,9 @@
 import type { FeedSource } from "@aelis/core"
 
 export interface FeedSourceProvider {
-	feedSourceForUser(userId: string): FeedSource
+	feedSourceForUser(userId: string): Promise<FeedSource>
 }
 
-export type FeedSourceProviderFn = (userId: string) => FeedSource
+export type FeedSourceProviderFn = (userId: string) => Promise<FeedSource>
 
 export type FeedSourceProviderInput = FeedSourceProvider | FeedSourceProviderFn

apps/aelis-backend/src/session/user-session-manager.test.ts

@@ -1,7 +1,7 @@
 import type { WeatherKitClient, WeatherKitResponse } from "@aelis/source-weatherkit"
 
 import { LocationSource } from "@aelis/source-location"
-import { describe, expect, mock, test } from "bun:test"
+import { describe, expect, mock, spyOn, test } from "bun:test"
 
 import { WeatherSourceProvider } from "../weather/provider.ts"
 import { UserSessionManager } from "./user-session-manager.ts"
@@ -11,38 +11,38 @@ const mockWeatherClient: WeatherKitClient = {
 }
 
 describe("UserSessionManager", () => {
-	test("getOrCreate creates session on first call", () => {
+	test("getOrCreate creates session on first call", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 
-		const session = manager.getOrCreate("user-1")
+		const session = await manager.getOrCreate("user-1")
 
 		expect(session).toBeDefined()
 		expect(session.engine).toBeDefined()
 	})
 
-	test("getOrCreate returns same session for same user", () => {
+	test("getOrCreate returns same session for same user", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 
-		const session1 = manager.getOrCreate("user-1")
+		const session1 = await manager.getOrCreate("user-1")
-		const session2 = manager.getOrCreate("user-1")
+		const session2 = await manager.getOrCreate("user-1")
 
 		expect(session1).toBe(session2)
 	})
 
-	test("getOrCreate returns different sessions for different users", () => {
+	test("getOrCreate returns different sessions for different users", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 
-		const session1 = manager.getOrCreate("user-1")
+		const session1 = await manager.getOrCreate("user-1")
-		const session2 = manager.getOrCreate("user-2")
+		const session2 = await manager.getOrCreate("user-2")
 
 		expect(session1).not.toBe(session2)
 	})
 
-	test("each user gets independent source instances", () => {
+	test("each user gets independent source instances", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 
-		const session1 = manager.getOrCreate("user-1")
+		const session1 = await manager.getOrCreate("user-1")
-		const session2 = manager.getOrCreate("user-2")
+		const session2 = await manager.getOrCreate("user-2")
 
 		const source1 = session1.getSource<LocationSource>("aelis.location")
 		const source2 = session2.getSource<LocationSource>("aelis.location")
@@ -50,58 +50,58 @@ describe("UserSessionManager", () => {
 		expect(source1).not.toBe(source2)
 	})
 
-	test("remove destroys session and allows re-creation", () => {
+	test("remove destroys session and allows re-creation", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 
-		const session1 = manager.getOrCreate("user-1")
+		const session1 = await manager.getOrCreate("user-1")
 		manager.remove("user-1")
-		const session2 = manager.getOrCreate("user-1")
+		const session2 = await manager.getOrCreate("user-1")
 
 		expect(session1).not.toBe(session2)
 	})
 
 	test("remove is no-op for unknown user", () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 
 		expect(() => manager.remove("unknown")).not.toThrow()
 	})
 
 	test("accepts function providers", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 
-		const session = manager.getOrCreate("user-1")
+		const session = await manager.getOrCreate("user-1")
 		const result = await session.engine.refresh()
 
 		expect(result.errors).toHaveLength(0)
 	})
 
-	test("accepts object providers", () => {
+	test("accepts object providers", async () => {
 		const provider = new WeatherSourceProvider({ client: mockWeatherClient })
 		const manager = new UserSessionManager({
-			providers: [() => new LocationSource(), provider],
+			providers: [async () => new LocationSource(), provider],
 		})
 
-		const session = manager.getOrCreate("user-1")
+		const session = await manager.getOrCreate("user-1")
 
 		expect(session.getSource("aelis.weather")).toBeDefined()
 	})
 
-	test("accepts mixed providers", () => {
+	test("accepts mixed providers", async () => {
 		const provider = new WeatherSourceProvider({ client: mockWeatherClient })
 		const manager = new UserSessionManager({
-			providers: [() => new LocationSource(), provider],
+			providers: [async () => new LocationSource(), provider],
 		})
 
-		const session = manager.getOrCreate("user-1")
+		const session = await manager.getOrCreate("user-1")
 
 		expect(session.getSource("aelis.location")).toBeDefined()
 		expect(session.getSource("aelis.weather")).toBeDefined()
 	})
 
 	test("refresh returns feed result through session", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 
-		const session = manager.getOrCreate("user-1")
+		const session = await manager.getOrCreate("user-1")
 		const result = await session.engine.refresh()
 
 		expect(result).toHaveProperty("context")
@@ -111,9 +111,9 @@ describe("UserSessionManager", () => {
 	})
 
 	test("location update via executeAction works", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 
-		const session = manager.getOrCreate("user-1")
+		const session = await manager.getOrCreate("user-1")
 		await session.engine.executeAction("aelis.location", "update-location", {
 			lat: 51.5074,
 			lng: -0.1278,
@@ -126,10 +126,10 @@ describe("UserSessionManager", () => {
 	})
 
 	test("subscribe receives updates after location push", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 		const callback = mock()
 
-		const session = manager.getOrCreate("user-1")
+		const session = await manager.getOrCreate("user-1")
 		session.engine.subscribe(callback)
 
 		await session.engine.executeAction("aelis.location", "update-location", {
@@ -146,16 +146,16 @@ describe("UserSessionManager", () => {
 	})
 
 	test("remove stops reactive updates", async () => {
-		const manager = new UserSessionManager({ providers: [() => new LocationSource()] })
+		const manager = new UserSessionManager({ providers: [async () => new LocationSource()] })
 		const callback = mock()
 
-		const session = manager.getOrCreate("user-1")
+		const session = await manager.getOrCreate("user-1")
 		session.engine.subscribe(callback)
 
 		manager.remove("user-1")
 
 		// Create new session and push location — old callback should not fire
-		const session2 = manager.getOrCreate("user-1")
+		const session2 = await manager.getOrCreate("user-1")
 		await session2.engine.executeAction("aelis.location", "update-location", {
 			lat: 51.5074,
 			lng: -0.1278,
@@ -167,4 +167,93 @@ describe("UserSessionManager", () => {
 
 		expect(callback).not.toHaveBeenCalled()
 	})
+
+	test("creates session with successful providers when some fail", async () => {
+		const manager = new UserSessionManager({
+			providers: [
+				async () => new LocationSource(),
+				async () => {
+					throw new Error("provider failed")
+				},
+			],
+		})
+
+		const spy = spyOn(console, "error").mockImplementation(() => {})
+
+		const session = await manager.getOrCreate("user-1")
+
+		expect(session).toBeDefined()
+		expect(session.getSource("aelis.location")).toBeDefined()
+		expect(spy).toHaveBeenCalled()
+
+		spy.mockRestore()
+	})
+
+	test("throws AggregateError when all providers fail", async () => {
+		const manager = new UserSessionManager({
+			providers: [
+				async () => {
+					throw new Error("first failed")
+				},
+				async () => {
+					throw new Error("second failed")
+				},
+			],
+		})
+
+		await expect(manager.getOrCreate("user-1")).rejects.toBeInstanceOf(AggregateError)
+	})
+
+	test("concurrent getOrCreate for same user returns same session", async () => {
+		let callCount = 0
+		const manager = new UserSessionManager({
+			providers: [
+				async () => {
+					callCount++
+					// Simulate async work to widen the race window
+					await new Promise((resolve) => setTimeout(resolve, 10))
+					return new LocationSource()
+				},
+			],
+		})
+
+		const [session1, session2] = await Promise.all([
+			manager.getOrCreate("user-1"),
+			manager.getOrCreate("user-1"),
+		])
+
+		expect(session1).toBe(session2)
+		expect(callCount).toBe(1)
+	})
+
+	test("remove during in-flight getOrCreate prevents session from being stored", async () => {
+		let resolveProvider: () => void
+		const providerGate = new Promise<void>((r) => {
+			resolveProvider = r
+		})
+
+		const manager = new UserSessionManager({
+			providers: [
+				async () => {
+					await providerGate
+					return new LocationSource()
+				},
+			],
+		})
+
+		const sessionPromise = manager.getOrCreate("user-1")
+
+		// remove() while provider is still resolving
+		manager.remove("user-1")
+
+		// Let the provider finish
+		resolveProvider!()
+
+		await expect(sessionPromise).rejects.toThrow("removed during creation")
+
+		// A fresh getOrCreate should produce a new session, not the cancelled one
+		const freshSession = await manager.getOrCreate("user-1")
+		expect(freshSession).toBeDefined()
+		expect(freshSession.engine).toBeDefined()
+	})
 })

apps/aelis-backend/src/session/user-session-manager.ts

@@ -1,3 +1,5 @@
+import type { FeedSource } from "@aelis/core"
+
 import type { FeedEnhancer } from "../enhancement/enhance-feed.ts"
 import type { FeedSourceProviderInput } from "./feed-source-provider.ts"
 
@@ -10,6 +12,7 @@ export interface UserSessionManagerConfig {
 
 export class UserSessionManager {
 	private sessions = new Map<string, UserSession>()
+	private pending = new Map<string, Promise<UserSession>>()
 	private readonly providers: FeedSourceProviderInput[]
 	private readonly feedEnhancer: FeedEnhancer | null
 
@@ -18,16 +21,28 @@ export class UserSessionManager {
 		this.feedEnhancer = config.feedEnhancer ?? null
 	}
 
-	getOrCreate(userId: string): UserSession {
+	async getOrCreate(userId: string): Promise<UserSession> {
-		let session = this.sessions.get(userId)
+		const existing = this.sessions.get(userId)
-		if (!session) {
+		if (existing) return existing
-			const sources = this.providers.map((p) =>
+
-				typeof p === "function" ? p(userId) : p.feedSourceForUser(userId),
+		const inflight = this.pending.get(userId)
-			)
+		if (inflight) return inflight
-			session = new UserSession(sources, this.feedEnhancer)
+
-			this.sessions.set(userId, session)
+		const promise = this.createSession(userId)
+		this.pending.set(userId, promise)
+		try {
+			const session = await promise
+			// If remove() was called while we were awaiting, it clears the
+			// pending entry. Detect that and destroy the session immediately.
+			if (!this.pending.has(userId)) {
+				session.destroy()
+				throw new Error(`Session for user ${userId} was removed during creation`)
 			}
+			this.sessions.set(userId, session)
 			return session
+		} finally {
+			this.pending.delete(userId)
+		}
 	}
 
 	remove(userId: string): void {
@@ -36,5 +51,36 @@ export class UserSessionManager {
 			session.destroy()
 			this.sessions.delete(userId)
 		}
+		// Cancel any in-flight creation so getOrCreate won't store the session
+		this.pending.delete(userId)
+	}
+
+	private async createSession(userId: string): Promise<UserSession> {
+		const results = await Promise.allSettled(
+			this.providers.map((p) =>
+				typeof p === "function" ? p(userId) : p.feedSourceForUser(userId),
+			),
+		)
+
+		const sources: FeedSource[] = []
+		const errors: unknown[] = []
+
+		for (const result of results) {
+			if (result.status === "fulfilled") {
+				sources.push(result.value)
+			} else {
+				errors.push(result.reason)
+			}
+		}
+
+		if (sources.length === 0 && errors.length > 0) {
+			throw new AggregateError(errors, "All feed source providers failed")
+		}
+
+		for (const error of errors) {
+			console.error("[UserSessionManager] Feed source provider failed:", error)
+		}
+
+		return new UserSession(sources, this.feedEnhancer)
 	}
 }

apps/aelis-backend/src/session/user-session.test.ts

@@ -76,6 +76,7 @@ describe("UserSession.feed", () => {
 		const items: FeedItem[] = [
 			{
 				id: "item-1",
+				sourceId: "test",
 				type: "test",
 				timestamp: new Date("2025-01-01T00:00:00.000Z"),
 				data: { value: 42 },
@@ -93,6 +94,7 @@ describe("UserSession.feed", () => {
 		const items: FeedItem[] = [
 			{
 				id: "item-1",
+				sourceId: "test",
 				type: "test",
 				timestamp: new Date("2025-01-01T00:00:00.000Z"),
 				data: { value: 42 },
@@ -113,6 +115,7 @@ describe("UserSession.feed", () => {
 		const items: FeedItem[] = [
 			{
 				id: "item-1",
+				sourceId: "test",
 				type: "test",
 				timestamp: new Date("2025-01-01T00:00:00.000Z"),
 				data: { value: 42 },
@@ -139,6 +142,7 @@ describe("UserSession.feed", () => {
 		let currentItems: FeedItem[] = [
 			{
 				id: "item-1",
+				sourceId: "test",
 				type: "test",
 				timestamp: new Date("2025-01-01T00:00:00.000Z"),
 				data: { version: 1 },
@@ -169,6 +173,7 @@ describe("UserSession.feed", () => {
 		currentItems = [
 			{
 				id: "item-1",
+				sourceId: "test",
 				type: "test",
 				timestamp: new Date("2025-01-02T00:00:00.000Z"),
 				data: { version: 2 },
@@ -190,6 +195,7 @@ describe("UserSession.feed", () => {
 		const items: FeedItem[] = [
 			{
 				id: "item-1",
+				sourceId: "test",
 				type: "test",
 				timestamp: new Date("2025-01-01T00:00:00.000Z"),
 				data: { value: 42 },

apps/aelis-backend/src/tfl/provider.ts

@@ -13,7 +13,7 @@ export class TflSourceProvider implements FeedSourceProvider {
 		this.options = options
 	}
 
-	feedSourceForUser(_userId: string): TflSource {
+	async feedSourceForUser(_userId: string): Promise<TflSource> {
 		return new TflSource(this.options)
 	}
 }

apps/aelis-backend/src/weather/provider.ts

@@ -9,7 +9,7 @@ export class WeatherSourceProvider implements FeedSourceProvider {
 		this.options = options
 	}
 
-	feedSourceForUser(_userId: string): WeatherSource {
+	async feedSourceForUser(_userId: string): Promise<WeatherSource> {
 		return new WeatherSource(this.options)
 	}
 }

apps/aelis-client/package.json

@@ -22,6 +22,7 @@
 		"@react-navigation/bottom-tabs": "^7.4.0",
 		"@react-navigation/elements": "^2.6.3",
 		"@react-navigation/native": "^7.1.8",
+		"@tanstack/react-query": "^5.90.21",
 		"expo": "~54.0.33",
 		"expo-constants": "~18.0.13",
 		"expo-dev-client": "~6.0.20",

apps/aelis-client/src/api/auth-middleware.ts

@@ -0,0 +1,6 @@
+import { ApiRequestMiddleware } from "./client"
+
+export const authMiddleware: ApiRequestMiddleware = (_url, init) => {
+	// TODO: placeholder auth middleware
+	return init
+}

apps/aelis-client/src/api/client.ts

@@ -0,0 +1,39 @@
+import { createContext, useContext } from "react"
+
+export type ApiRequestMiddleware = (
+	url: Parameters<typeof fetch>[0],
+	init: RequestInit,
+) => RequestInit
+
+export class ApiClient {
+	private readonly baseUrl: string
+	private readonly middlewares: readonly ApiRequestMiddleware[]
+
+	static noop = new ApiClient({ baseUrl: "" })
+
+	constructor({
+		baseUrl,
+		middlewares = [],
+	}: {
+		baseUrl: string
+		middlewares?: ApiRequestMiddleware[]
+	}) {
+		this.baseUrl = baseUrl
+		this.middlewares = middlewares
+	}
+
+	async request<T>(...[url, init = {}]: Parameters<typeof fetch>): Promise<[Response, T]> {
+		const finalInit = this.middlewares.reduce(
+			(prevInit, middleware) => middleware(url, prevInit),
+			init,
+		)
+		return fetch(this.baseUrl ? new URL(url.toString(), this.baseUrl) : url, finalInit).then((res) =>
+			Promise.all([Promise.resolve(res), res.json()]),
+		)
+	}
+}
+
+export const ApiClientContext = createContext(ApiClient.noop)
+export function useApiClient() {
+	return useContext(ApiClientContext)
+}

apps/aelis-client/src/app/_layout.tsx

@@ -1,17 +1,29 @@
 import "react-native-reanimated"
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query"
 import { Stack } from "expo-router"
 import { StatusBar } from "expo-status-bar"
+import React from "react"
 import { useColorScheme } from "react-native"
 import tw, { useDeviceContext } from "twrnc"
 
+import { authMiddleware } from "@/api/auth-middleware"
+import { ApiClient, ApiClientContext } from "@/api/client"
+
+const queryClient = new QueryClient()
+const apiClient = new ApiClient({
+	baseUrl: process.env.EXPO_PUBLIC_API_BASE_URL ?? "",
+	middlewares: [authMiddleware],
+})
+
 export default function RootLayout() {
 	useDeviceContext(tw)
+
 	const colorScheme = useColorScheme()
 	const headerBg = colorScheme === "dark" ? "#1c1917" : "#f5f5f4"
 	const headerTint = colorScheme === "dark" ? "#e7e5e4" : "#1c1917"
 
 	return (
-		<>
+		<ContextProvider>
 			<Stack
 				screenOptions={{
 					headerShown: false,
@@ -40,6 +52,14 @@ export default function RootLayout() {
 				/>
 			</Stack>
 			<StatusBar style="auto" />
-		</>
+		</ContextProvider>
+	)
+}
+
+function ContextProvider({ children }: React.PropsWithChildren) {
+	return (
+		<QueryClientProvider client={queryClient}>
+			<ApiClientContext value={apiClient}>{children}</ApiClientContext>
+		</QueryClientProvider>
 	)
 }

apps/aelis-client/src/feed/queries.ts

@@ -0,0 +1,13 @@
+import { queryOptions } from "@tanstack/react-query"
+
+import { useApiClient } from "@/api/client"
+
+import { FeedItem } from "./types"
+
+export function useFeedQuery() {
+	const api = useApiClient()
+	return queryOptions({
+		queryKey: ["feed"],
+		queryFn: async () => api.request<{ items: FeedItem[] }>("/feed?render=json-render"),
+	})
+}

apps/aelis-client/src/feed/types.ts

@@ -0,0 +1,5 @@
+import { Spec } from "@json-render/core"
+
+export interface FeedItem {
+	ui: Spec
+}

bun.lock

@@ -6,7 +6,7 @@
       "name": "aelis",
       "devDependencies": {
         "@json-render/core": "^0.12.1",
-        "@nym.sh/jrx": "^0.1.0",
+        "@nym.sh/jrx": "^0.2.0",
         "@types/bun": "latest",
         "oxfmt": "^0.24.0",
         "oxlint": "^1.39.0",
@@ -46,6 +46,7 @@
         "@react-navigation/bottom-tabs": "^7.4.0",
         "@react-navigation/elements": "^2.6.3",
         "@react-navigation/native": "^7.1.8",
+        "@tanstack/react-query": "^5.90.21",
         "expo": "~54.0.33",
         "expo-constants": "~18.0.13",
         "expo-dev-client": "~6.0.20",
@@ -152,6 +153,7 @@
       "name": "@aelis/source-caldav",
       "version": "0.0.0",
       "dependencies": {
+        "@aelis/components": "workspace:*",
         "@aelis/core": "workspace:*",
         "ical.js": "^2.1.0",
         "tsdav": "^2.1.7",
@@ -177,10 +179,15 @@
       "name": "@aelis/source-tfl",
       "version": "0.0.0",
       "dependencies": {
+        "@aelis/components": "workspace:*",
         "@aelis/core": "workspace:*",
         "@aelis/source-location": "workspace:*",
         "arktype": "^2.1.0",
       },
+      "peerDependencies": {
+        "@json-render/core": "*",
+        "@nym.sh/jrx": "*",
+      },
     },
     "packages/aelis-source-weatherkit": {
       "name": "@aelis/source-weatherkit",
@@ -691,7 +698,7 @@
 
     "@nolyfill/is-core-module": ["@nolyfill/is-core-module@1.0.39", "", {}, "sha512-nn5ozdjYQpUCZlWGuxcJY/KpxkWQs4DcbMCmKojjyrYDEAGy4Ce19NN4v5MduafTwJlbKc99UA8YhSVqq9yPZA=="],
 
-    "@nym.sh/jrx": ["@nym.sh/jrx@0.1.0", "", { "peerDependencies": { "@json-render/core": ">=0.10.0" } }, "sha512-mu6fkAP/TI9FuP8A4WMCrcucpUtWF5xBTcETnrjOtvEED9i+7sQKuoOyhJeF6QaSuUkAA/8t3Xx3kYUjcAPFbw=="],
+    "@nym.sh/jrx": ["@nym.sh/jrx@0.2.0", "", { "peerDependencies": { "@json-render/core": ">=0.10.0" } }, "sha512-jd7Z1Q6T21366MtSUnwCFiu6Yl1AdNc9s5m6HxeUg265P+0enZCiyyxOuHsFwvpUcSEs/2DVBsqfMptdca44lA=="],
 
     "@oclif/core": ["@oclif/core@4.8.4", "", { "dependencies": { "ansi-escapes": "^4.3.2", "ansis": "^3.17.0", "clean-stack": "^3.0.1", "cli-spinners": "^2.9.2", "debug": "^4.4.3", "ejs": "^3.1.10", "get-package-type": "^0.1.0", "indent-string": "^4.0.0", "is-wsl": "^2.2.0", "lilconfig": "^3.1.3", "minimatch": "^10.2.4", "semver": "^7.7.3", "string-width": "^4.2.3", "supports-color": "^8", "tinyglobby": "^0.2.14", "widest-line": "^3.1.0", "wordwrap": "^1.0.0", "wrap-ansi": "^7.0.0" } }, "sha512-UTAqwXJJyRvLBvosL+1uPZYSpr8lEHgUb/EVGbPXo5WZqUIBHfJ0sR2bkBEsrj00/ar4IegKxx4YK0wn2c8SQg=="],
 
@@ -1183,6 +1190,10 @@
 
     "@tailwindcss/vite": ["@tailwindcss/vite@4.2.1", "", { "dependencies": { "@tailwindcss/node": "4.2.1", "@tailwindcss/oxide": "4.2.1", "tailwindcss": "4.2.1" }, "peerDependencies": { "vite": "^5.2.0 || ^6 || ^7" } }, "sha512-TBf2sJjYeb28jD2U/OhwdW0bbOsxkWPwQ7SrqGf9sVcoYwZj7rkXljroBO9wKBut9XnmQLXanuDUeqQK0lGg/w=="],
 
+    "@tanstack/query-core": ["@tanstack/query-core@5.90.20", "", {}, "sha512-OMD2HLpNouXEfZJWcKeVKUgQ5n+n3A2JFmBaScpNDUqSrQSjiveC7dKMe53uJUg1nDG16ttFPz2xfilz6i2uVg=="],
+
+    "@tanstack/react-query": ["@tanstack/react-query@5.90.21", "", { "dependencies": { "@tanstack/query-core": "5.90.20" }, "peerDependencies": { "react": "^18 || ^19" } }, "sha512-0Lu6y5t+tvlTJMTO7oh5NSpJfpg/5D41LlThfepTixPYkJ0sE2Jj0m0f6yYqujBwIXlId87e234+MxG3D3g7kg=="],
+
     "@tsconfig/node10": ["@tsconfig/node10@1.0.12", "", {}, "sha512-UCYBaeFvM11aU2y3YPZ//O5Rhj+xKyzy7mvcIoAjASbigy8mHMryP5cK7dgjlz2hWxh1g5pLw084E0a/wlUSFQ=="],
 
     "@tsconfig/node12": ["@tsconfig/node12@1.0.11", "", {}, "sha512-cqefuRsh12pWyGsIoBKJA9luFu3mRxCA+ORZvA4ktLSzIuCUtWVxGIuXigEwO5/ywWFMZ2QEGKWvkZG1zDMTag=="],

package.json

@@ -15,7 +15,7 @@
 	},
 	"devDependencies": {
 		"@json-render/core": "^0.12.1",
-		"@nym.sh/jrx": "^0.1.0",
+		"@nym.sh/jrx": "^0.2.0",
 		"@types/bun": "latest",
 		"oxfmt": "^0.24.0",
 		"oxlint": "^1.39.0"

packages/aelis-core/src/data-source.ts

@@ -17,6 +17,7 @@ import type { FeedItem } from "./feed"
  *     const data = await fetchWeather(location)
  *     return [{
  *       id: `weather-${Date.now()}`,
+ *       sourceId: "aelis.weather",
  *       type: this.type,
  *       timestamp: context.time,
  *       data: { temp: data.temperature },

packages/aelis-core/src/feed-engine.test.ts

@@ -99,6 +99,7 @@ function createWeatherSource(
 			return [
 				{
 					id: `weather-${Date.now()}`,
+					sourceId: "weather",
 					type: "weather",
 					timestamp: new Date(),
 					data: {
@@ -130,6 +131,7 @@ function createAlertSource(): FeedSource<AlertFeedItem> {
 				return [
 					{
 						id: "alert-storm",
+						sourceId: "alert",
 						type: "alert",
 						timestamp: new Date(),
 						data: { message: "Storm warning!" },
@@ -423,6 +425,7 @@ describe("FeedEngine", () => {
 					return [
 						{
 							id: "item-1",
+							sourceId: "working",
 							type: "test",
 							priority: 0.5,
 							timestamp: new Date(),
@@ -746,6 +749,7 @@ describe("FeedEngine", () => {
 					return [
 						{
 							id: "item-1",
+							sourceId: "reactive-items",
 							type: "test",
 							priority: 0.5,
 							timestamp: new Date(),
@@ -830,6 +834,7 @@ describe("FeedEngine", () => {
 					return [
 						{
 							id: `item-${fetchCount}`,
+							sourceId: "counter",
 							type: "test",
 							priority: 0.5,
 							timestamp: new Date(),
@@ -895,6 +900,7 @@ describe("FeedEngine", () => {
 					return [
 						{
 							id: `weather-${Date.now()}`,
+							sourceId: "weather",
 							type: "weather",
 							priority: 0.5,
 							timestamp: new Date(),

packages/aelis-core/src/feed-post-processor.test.ts

@@ -29,11 +29,17 @@ type WeatherItem = FeedItem<"weather", { temp: number }>
 type CalendarItem = FeedItem<"calendar", { title: string }>
 
 function weatherItem(id: string, temp: number): WeatherItem {
-	return { id, type: "weather", timestamp: new Date(), data: { temp } }
+	return { id, sourceId: "aelis.weather", type: "weather", timestamp: new Date(), data: { temp } }
 }
 
 function calendarItem(id: string, title: string): CalendarItem {
-	return { id, type: "calendar", timestamp: new Date(), data: { title } }
+	return {
+		id,
+		sourceId: "aelis.calendar",
+		type: "calendar",
+		timestamp: new Date(),
+		data: { title },
+	}
 }
 
 // =============================================================================

packages/aelis-core/src/feed-source.test.ts

@@ -98,6 +98,7 @@ function createWeatherSource(
 			return [
 				{
 					id: `weather-${Date.now()}`,
+					sourceId: "weather",
 					type: "weather",
 					timestamp: new Date(),
 					data: {
@@ -129,6 +130,7 @@ function createAlertSource(): FeedSource<AlertFeedItem> {
 				return [
 					{
 						id: "alert-storm",
+						sourceId: "alert",
 						type: "alert",
 						timestamp: new Date(),
 						data: { message: "Storm warning!" },

packages/aelis-core/src/feed.test.ts

@@ -6,6 +6,7 @@ describe("FeedItem slots", () => {
 	test("FeedItem without slots is valid", () => {
 		const item: FeedItem<"test", { value: number }> = {
 			id: "test-1",
+			sourceId: "test-source",
 			type: "test",
 			timestamp: new Date(),
 			data: { value: 42 },
@@ -17,6 +18,7 @@ describe("FeedItem slots", () => {
 	test("FeedItem with unfilled slots", () => {
 		const item: FeedItem<"weather", { temp: number }> = {
 			id: "weather-1",
+			sourceId: "aelis.weather",
 			type: "weather",
 			timestamp: new Date(),
 			data: { temp: 18 },
@@ -41,6 +43,7 @@ describe("FeedItem slots", () => {
 	test("FeedItem with filled slots", () => {
 		const item: FeedItem<"weather", { temp: number }> = {
 			id: "weather-1",
+			sourceId: "aelis.weather",
 			type: "weather",
 			timestamp: new Date(),
 			data: { temp: 18 },
@@ -75,6 +78,7 @@ describe("FeedItem slots", () => {
 	test("FeedItem with empty slots record", () => {
 		const item: FeedItem<"test", { value: number }> = {
 			id: "test-1",
+			sourceId: "test-source",
 			type: "test",
 			timestamp: new Date(),
 			data: { value: 1 },

packages/aelis-core/src/feed.ts

@@ -48,6 +48,7 @@ export interface Slot {
  *
  * const item: WeatherItem = {
  *   id: "weather-123",
+ *   sourceId: "aelis.weatherkit",
  *   type: "weather",
  *   timestamp: new Date(),
  *   data: { temp: 18, condition: "cloudy" },
@@ -67,6 +68,8 @@ export interface FeedItem<
 > {
 	/** Unique identifier */
 	id: string
+	/** ID of the FeedSource that produced this item */
+	sourceId: string
 	/** Item type, matches the data source type */
 	type: TType
 	/** When this item was generated */

packages/aelis-data-source-weatherkit/src/data-source.ts

@@ -47,6 +47,8 @@ interface LocationData {
 
 const LocationKey: ContextKey<LocationData> = contextKey("aelis.location", "location")
 
+const SOURCE_ID = "aelis.weather"
+
 export class WeatherKitDataSource implements DataSource<WeatherFeedItem, WeatherKitQueryConfig> {
 	private readonly DEFAULT_HOURLY_LIMIT = 12
 	private readonly DEFAULT_DAILY_LIMIT = 7
@@ -236,6 +238,7 @@ function createCurrentWeatherFeedItem(
 
 	return {
 		id: `weather-current-${timestamp.getTime()}`,
+		sourceId: SOURCE_ID,
 		type: WeatherFeedItemType.Current,
 		timestamp,
 		data: {
@@ -270,6 +273,7 @@ function createHourlyWeatherFeedItem(
 
 	return {
 		id: `weather-hourly-${timestamp.getTime()}-${index}`,
+		sourceId: SOURCE_ID,
 		type: WeatherFeedItemType.Hourly,
 		timestamp,
 		data: {
@@ -304,6 +308,7 @@ function createDailyWeatherFeedItem(
 
 	return {
 		id: `weather-daily-${timestamp.getTime()}-${index}`,
+		sourceId: SOURCE_ID,
 		type: WeatherFeedItemType.Daily,
 		timestamp,
 		data: {
@@ -331,6 +336,7 @@ function createWeatherAlertFeedItem(alert: WeatherAlert, timestamp: Date): Weath
 
 	return {
 		id: `weather-alert-${alert.id}`,
+		sourceId: SOURCE_ID,
 		type: WeatherFeedItemType.Alert,
 		timestamp,
 		data: {

packages/aelis-feed-enhancers/src/time-of-day-enhancer.test.ts

@@ -40,6 +40,7 @@ function saturday(hour: number, minute = 0): Date {
 function weatherCurrent(id = "w-current"): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.weather",
 		type: WeatherFeedItemType.Current,
 		timestamp: new Date(),
 		data: { temperature: 18, precipitationIntensity: 0 },
@@ -49,6 +50,7 @@ function weatherCurrent(id = "w-current"): FeedItem {
 function weatherCurrentRainy(id = "w-current-rain"): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.weather",
 		type: WeatherFeedItemType.Current,
 		timestamp: new Date(),
 		data: { temperature: 12, precipitationIntensity: 2.5 },
@@ -58,6 +60,7 @@ function weatherCurrentRainy(id = "w-current-rain"): FeedItem {
 function weatherCurrentExtreme(id = "w-current-extreme"): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.weather",
 		type: WeatherFeedItemType.Current,
 		timestamp: new Date(),
 		data: { temperature: -5, precipitationIntensity: 0 },
@@ -67,6 +70,7 @@ function weatherCurrentExtreme(id = "w-current-extreme"): FeedItem {
 function weatherHourly(id = "w-hourly"): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.weather",
 		type: WeatherFeedItemType.Hourly,
 		timestamp: new Date(),
 		data: { forecastTime: new Date(), temperature: 20 },
@@ -76,6 +80,7 @@ function weatherHourly(id = "w-hourly"): FeedItem {
 function weatherDaily(id = "w-daily"): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.weather",
 		type: WeatherFeedItemType.Daily,
 		timestamp: new Date(),
 		data: { forecastDate: new Date() },
@@ -85,6 +90,7 @@ function weatherDaily(id = "w-daily"): FeedItem {
 function weatherAlert(id = "w-alert", urgency = 0.9): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.weather",
 		type: WeatherFeedItemType.Alert,
 		timestamp: new Date(),
 		data: { severity: "extreme" },
@@ -99,6 +105,7 @@ function calendarEvent(
 ): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.google-calendar",
 		type: CalendarFeedItemType.Event,
 		timestamp: new Date(),
 		data: {
@@ -120,6 +127,7 @@ function calendarEvent(
 function calendarAllDay(id: string): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.google-calendar",
 		type: CalendarFeedItemType.AllDay,
 		timestamp: new Date(),
 		data: {
@@ -145,6 +153,7 @@ function caldavEvent(
 ): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.caldav",
 		type: CalDavFeedItemType.Event,
 		timestamp: new Date(),
 		data: {
@@ -170,6 +179,7 @@ function caldavEvent(
 function tflAlert(id = "tfl-1", urgency = 0.8): FeedItem {
 	return {
 		id,
+		sourceId: "aelis.tfl",
 		type: TflFeedItemType.Alert,
 		timestamp: new Date(),
 		data: {
@@ -185,6 +195,7 @@ function tflAlert(id = "tfl-1", urgency = 0.8): FeedItem {
 function unknownItem(id = "unknown-1"): FeedItem {
 	return {
 		id,
+		sourceId: "unknown",
 		type: "some-future-type",
 		timestamp: new Date(),
 		data: { foo: "bar" },

packages/aelis-source-caldav/package.json

@@ -9,6 +9,7 @@
 		"test:live": "bun run scripts/test-live.ts"
 	},
 	"dependencies": {
+		"@aelis/components": "workspace:*",
 		"@aelis/core": "workspace:*",
 		"ical.js": "^2.1.0",
 		"tsdav": "^2.1.7"

packages/aelis-source-caldav/src/caldav-source.ts

@@ -133,7 +133,7 @@ export class CalDavSource implements FeedSource<CalDavFeedItem> {
 	async fetchItems(context: Context): Promise<CalDavFeedItem[]> {
 		const now = context.time
 		const events = await this.fetchEvents(context)
-		return events.map((event) => createFeedItem(event, now, this.timeZone))
+		return events.map((event) => createFeedItem(event, now, this.id, this.timeZone))
 	}
 
 	private fetchEvents(context: Context): Promise<CalDavEventData[]> {
@@ -351,9 +351,15 @@ function createEventSlots(): Record<string, Slot> {
 	}
 }
 
-function createFeedItem(event: CalDavEventData, now: Date, timeZone?: string): CalDavFeedItem {
+function createFeedItem(
+	event: CalDavEventData,
+	now: Date,
+	sourceId: string,
+	timeZone?: string,
+): CalDavFeedItem {
 	return {
 		id: `caldav-event-${event.uid}${event.recurrenceId ? `-${event.recurrenceId}` : ""}`,
+		sourceId,
 		type: CalDavFeedItemType.Event,
 		timestamp: now,
 		data: event,

packages/aelis-source-caldav/src/index.ts

@@ -1,6 +1,7 @@
 export { CalDavCalendarKey, type CalendarContext } from "./calendar-context.ts"
 export { CalDavSource, type CalDavSourceOptions } from "./caldav-source.ts"
 export { parseICalEvents, type ICalTimeRange } from "./ical-parser.ts"
+export { renderCalDavFeedItem } from "./renderer.tsx"
 export {
 	AttendeeRole,
 	AttendeeStatus,

packages/aelis-source-caldav/src/renderer.tsx

@@ -0,0 +1,74 @@
+/** @jsxImportSource @nym.sh/jrx */
+
+import type { FeedItemRenderer } from "@aelis/core"
+
+import { FeedCard, SansSerifText, SerifText } from "@aelis/components"
+
+import type { CalDavEventData } from "./types.ts"
+
+import { CalDavEventStatus } from "./types.ts"
+
+function formatTime(date: Date): string {
+	const hours = date.getHours()
+	const minutes = date.getMinutes()
+	const period = hours >= 12 ? "PM" : "AM"
+	const h = hours % 12 || 12
+	const m = minutes.toString().padStart(2, "0")
+	return `${h}:${m} ${period}`
+}
+
+function formatTimeRange(data: CalDavEventData): string {
+	if (data.isAllDay) {
+		return "All day"
+	}
+	return `${formatTime(data.startDate)} – ${formatTime(data.endDate)}`
+}
+
+function formatStatus(status: CalDavEventData["status"]): string | null {
+	if (status === CalDavEventStatus.Cancelled) return "Cancelled"
+	if (status === CalDavEventStatus.Tentative) return "Tentative"
+	return null
+}
+
+export const renderCalDavFeedItem: FeedItemRenderer<"caldav-event", CalDavEventData> = (item) => {
+	const { data, slots } = item
+	const statusLabel = formatStatus(data.status)
+	const attendeeCount = data.attendees.length
+
+	return (
+		<FeedCard>
+			{statusLabel ? <SansSerifText content={statusLabel} style="text-xs uppercase" /> : null}
+
+			<SerifText content={data.title} style="text-lg" />
+
+			<SansSerifText content={formatTimeRange(data)} style="text-sm" />
+
+			{data.calendarName ? (
+				<SansSerifText content={data.calendarName} style="text-sm text-secondary" />
+			) : null}
+
+			{data.location ? (
+				<SansSerifText content={data.location} style="text-sm text-secondary" />
+			) : null}
+
+			{attendeeCount > 0 ? (
+				<SansSerifText
+					content={`${attendeeCount} attendee${attendeeCount === 1 ? "" : "s"}`}
+					style="text-sm text-secondary"
+				/>
+			) : null}
+
+			{slots?.insight?.content ? (
+				<SansSerifText content={slots.insight.content} style="text-sm" />
+			) : null}
+
+			{slots?.preparation?.content ? (
+				<SansSerifText content={slots.preparation.content} style="text-sm" />
+			) : null}
+
+			{slots?.crossSource?.content ? (
+				<SansSerifText content={slots.crossSource.content} style="text-sm" />
+			) : null}
+		</FeedCard>
+	)
+}

packages/aelis-source-caldav/tsconfig.json

@@ -0,0 +1,7 @@
+{
+	"extends": "../../tsconfig.json",
+	"compilerOptions": {
+		"jsxImportSource": "@nym.sh/jrx"
+	},
+	"include": ["src"]
+}

packages/aelis-source-google-calendar/src/google-calendar-source.ts

@@ -113,7 +113,7 @@ export class GoogleCalendarSource implements FeedSource<CalendarFeedItem> {
 		const now = context.time.getTime()
 		const lookaheadMs = this.lookaheadHours * 60 * 60 * 1000
 
-		return events.map((event) => createFeedItem(event, now, lookaheadMs))
+		return events.map((event) => createFeedItem(event, now, lookaheadMs, this.id))
 	}
 
 	private async resolveCalendarIds(): Promise<string[]> {
@@ -208,11 +208,13 @@ function createFeedItem(
 	event: CalendarEventData,
 	nowMs: number,
 	lookaheadMs: number,
+	sourceId: string,
 ): CalendarFeedItem {
 	const itemType = event.isAllDay ? CalendarFeedItemType.AllDay : CalendarFeedItemType.Event
 
 	return {
 		id: `calendar-${event.calendarId}-${event.eventId}`,
+		sourceId,
 		type: itemType,
 		timestamp: new Date(nowMs),
 		data: event,

packages/aelis-source-tfl/package.json

@@ -10,7 +10,12 @@
 	},
 	"dependencies": {
 		"@aelis/core": "workspace:*",
+		"@aelis/components": "workspace:*",
 		"@aelis/source-location": "workspace:*",
 		"arktype": "^2.1.0"
+	},
+	"peerDependencies": {
+		"@json-render/core": "*",
+		"@nym.sh/jrx": "*"
 	}
 }

packages/aelis-source-tfl/src/index.ts

@@ -11,3 +11,4 @@ export {
 	type TflLineStatus,
 	type TflSourceOptions,
 } from "./types.ts"
+export { renderTflAlert } from "./renderer.tsx"

packages/aelis-source-tfl/src/renderer.test.tsx

@@ -0,0 +1,103 @@
+/** @jsxImportSource @nym.sh/jrx */
+import { render } from "@nym.sh/jrx"
+import { describe, expect, test } from "bun:test"
+
+import type { TflAlertFeedItem } from "./types.ts"
+
+import { renderTflAlert } from "./renderer.tsx"
+
+function makeItem(overrides: Partial<TflAlertFeedItem["data"]> = {}): TflAlertFeedItem {
+	return {
+		id: "tfl-alert-northern-minor-delays",
+		type: "tfl-alert",
+		timestamp: new Date("2026-01-15T12:00:00Z"),
+		data: {
+			line: "northern",
+			lineName: "Northern",
+			severity: "minor-delays",
+			description: "Minor delays due to signal failure",
+			closestStationDistance: null,
+			...overrides,
+		},
+	}
+}
+
+describe("renderTflAlert", () => {
+	test("renders a FeedCard with title and description", () => {
+		const node = renderTflAlert(makeItem())
+		const spec = render(node)
+
+		const root = spec.elements[spec.root]!
+		expect(root.type).toBe("FeedCard")
+		expect(root.children!.length).toBeGreaterThanOrEqual(2)
+
+		const title = spec.elements[root.children![0]!]!
+		expect(title.type).toBe("SansSerifText")
+		expect(title.props.content).toBe("Northern · Minor delays")
+
+		const body = spec.elements[root.children![1]!]!
+		expect(body.type).toBe("SansSerifText")
+		expect(body.props.content).toBe("Minor delays due to signal failure")
+	})
+
+	test("shows nearest station distance when available", () => {
+		const node = renderTflAlert(makeItem({ closestStationDistance: 0.35 }))
+		const spec = render(node)
+
+		const root = spec.elements[spec.root]!
+		expect(root.children).toHaveLength(3)
+
+		const caption = spec.elements[root.children![2]!]!
+		expect(caption.type).toBe("SansSerifText")
+		expect(caption.props.content).toBe("Nearest station: 350m away")
+	})
+
+	test("formats distance in km when >= 1km", () => {
+		const node = renderTflAlert(makeItem({ closestStationDistance: 2.456 }))
+		const spec = render(node)
+
+		const root = spec.elements[spec.root]!
+		const caption = spec.elements[root.children![2]!]!
+		expect(caption.props.content).toBe("Nearest station: 2.5km away")
+	})
+
+	test("formats near-1km boundary as km not meters", () => {
+		const node = renderTflAlert(makeItem({ closestStationDistance: 0.9999 }))
+		const spec = render(node)
+
+		const root = spec.elements[spec.root]!
+		const caption = spec.elements[root.children![2]!]!
+		expect(caption.props.content).toBe("Nearest station: 1.0km away")
+	})
+
+	test("omits station distance when null", () => {
+		const node = renderTflAlert(makeItem({ closestStationDistance: null }))
+		const spec = render(node)
+
+		const root = spec.elements[spec.root]!
+		// Title + body only, no caption (empty fragment doesn't produce a child)
+		const children = root.children!.filter((key) => {
+			const el = spec.elements[key]
+			return el && el.type !== "Fragment"
+		})
+		expect(children).toHaveLength(2)
+	})
+
+	test("renders closure severity label", () => {
+		const node = renderTflAlert(makeItem({ severity: "closure", lineName: "Central" }))
+		const spec = render(node)
+
+		const root = spec.elements[spec.root]!
+		const title = spec.elements[root.children![0]!]!
+		expect(title.props.content).toBe("Central · Closed")
+	})
+
+	test("renders major delays severity label", () => {
+		const node = renderTflAlert(makeItem({ severity: "major-delays", lineName: "Jubilee" }))
+		const spec = render(node)
+
+		const root = spec.elements[spec.root]!
+		const title = spec.elements[root.children![0]!]!
+		expect(title.props.content).toBe("Jubilee · Major delays")
+	})
+})

packages/aelis-source-tfl/src/renderer.tsx

@@ -0,0 +1,40 @@
+/** @jsxImportSource @nym.sh/jrx */
+import type { FeedItemRenderer } from "@aelis/core"
+
+import { FeedCard, SansSerifText } from "@aelis/components"
+
+import type { TflAlertData } from "./types.ts"
+
+import { TflAlertSeverity } from "./types.ts"
+
+const SEVERITY_LABEL: Record<TflAlertSeverity, string> = {
+	[TflAlertSeverity.Closure]: "Closed",
+	[TflAlertSeverity.MajorDelays]: "Major delays",
+	[TflAlertSeverity.MinorDelays]: "Minor delays",
+}
+
+function formatDistance(km: number): string {
+	const meters = Math.round(km * 1000)
+	if (meters < 1000) {
+		return `${meters}m away`
+	}
+	return `${(meters / 1000).toFixed(1)}km away`
+}
+
+export const renderTflAlert: FeedItemRenderer<"tfl-alert", TflAlertData> = (item) => {
+	const { lineName, severity, description, closestStationDistance } = item.data
+	const severityLabel = SEVERITY_LABEL[severity]
+
+	return (
+		<FeedCard>
+			<SansSerifText content={`${lineName} · ${severityLabel}`} style="text-base font-semibold" />
+			<SansSerifText content={description} style="text-sm" />
+			{closestStationDistance !== null ? (
+				<SansSerifText
+					content={`Nearest station: ${formatDistance(closestStationDistance)}`}
+					style="text-xs text-stone-500"
+				/>
+			) : null}
+		</FeedCard>
+	)
+}

packages/aelis-source-tfl/src/tfl-source.ts

@@ -151,6 +151,7 @@ export class TflSource implements FeedSource<TflAlertFeedItem> {
 
 			return {
 				id: `tfl-alert-${status.lineId}-${status.severity}`,
+				sourceId: this.id,
 				type: TflFeedItemType.Alert,
 				timestamp: context.time,
 				data,

packages/aelis-source-tfl/tsconfig.json

@@ -0,0 +1,7 @@
+{
+	"extends": "../../tsconfig.json",
+	"compilerOptions": {
+		"jsxImportSource": "@nym.sh/jrx"
+	},
+	"include": ["src"]
+}

packages/aelis-source-weatherkit/src/weather-source.ts

@@ -167,7 +167,9 @@ export class WeatherSource implements FeedSource<WeatherFeedItem> {
 		const items: WeatherFeedItem[] = []
 
 		if (response.currentWeather) {
-			items.push(createCurrentWeatherFeedItem(response.currentWeather, timestamp, this.units))
+			items.push(
+				createCurrentWeatherFeedItem(response.currentWeather, timestamp, this.units, this.id),
+			)
 		}
 
 		if (response.forecastHourly?.hours) {
@@ -175,7 +177,7 @@ export class WeatherSource implements FeedSource<WeatherFeedItem> {
 			for (let i = 0; i < hours.length; i++) {
 				const hour = hours[i]
 				if (hour) {
-					items.push(createHourlyWeatherFeedItem(hour, i, timestamp, this.units))
+					items.push(createHourlyWeatherFeedItem(hour, i, timestamp, this.units, this.id))
 				}
 			}
 		}
@@ -185,14 +187,14 @@ export class WeatherSource implements FeedSource<WeatherFeedItem> {
 			for (let i = 0; i < days.length; i++) {
 				const day = days[i]
 				if (day) {
-					items.push(createDailyWeatherFeedItem(day, i, timestamp, this.units))
+					items.push(createDailyWeatherFeedItem(day, i, timestamp, this.units, this.id))
 				}
 			}
 		}
 
 		if (response.weatherAlerts?.alerts) {
 			for (const alert of response.weatherAlerts.alerts) {
-				items.push(createWeatherAlertFeedItem(alert, timestamp))
+				items.push(createWeatherAlertFeedItem(alert, timestamp, this.id))
 			}
 		}
 
@@ -284,6 +286,7 @@ function createCurrentWeatherFeedItem(
 	current: CurrentWeather,
 	timestamp: Date,
 	units: Units,
+	sourceId: string,
 ): WeatherFeedItem {
 	const signals: FeedItemSignals = {
 		urgency: adjustUrgencyForCondition(BASE_URGENCY.current, current.conditionCode),
@@ -292,6 +295,7 @@ function createCurrentWeatherFeedItem(
 
 	return {
 		id: `weather-current-${timestamp.getTime()}`,
+		sourceId,
 		type: WeatherFeedItemType.Current,
 		timestamp,
 		data: {
@@ -324,6 +328,7 @@ function createHourlyWeatherFeedItem(
 	index: number,
 	timestamp: Date,
 	units: Units,
+	sourceId: string,
 ): WeatherFeedItem {
 	const signals: FeedItemSignals = {
 		urgency: adjustUrgencyForCondition(BASE_URGENCY.hourly, hourly.conditionCode),
@@ -332,6 +337,7 @@ function createHourlyWeatherFeedItem(
 
 	return {
 		id: `weather-hourly-${timestamp.getTime()}-${index}`,
+		sourceId,
 		type: WeatherFeedItemType.Hourly,
 		timestamp,
 		data: {
@@ -358,6 +364,7 @@ function createDailyWeatherFeedItem(
 	index: number,
 	timestamp: Date,
 	units: Units,
+	sourceId: string,
 ): WeatherFeedItem {
 	const signals: FeedItemSignals = {
 		urgency: adjustUrgencyForCondition(BASE_URGENCY.daily, daily.conditionCode),
@@ -366,6 +373,7 @@ function createDailyWeatherFeedItem(
 
 	return {
 		id: `weather-daily-${timestamp.getTime()}-${index}`,
+		sourceId,
 		type: WeatherFeedItemType.Daily,
 		timestamp,
 		data: {
@@ -385,7 +393,11 @@ function createDailyWeatherFeedItem(
 	}
 }
 
-function createWeatherAlertFeedItem(alert: WeatherAlert, timestamp: Date): WeatherFeedItem {
+function createWeatherAlertFeedItem(
+	alert: WeatherAlert,
+	timestamp: Date,
+	sourceId: string,
+): WeatherFeedItem {
 	const signals: FeedItemSignals = {
 		urgency: adjustUrgencyForAlertSeverity(alert.severity),
 		timeRelevance: timeRelevanceForAlertSeverity(alert.severity),
@@ -393,6 +405,7 @@ function createWeatherAlertFeedItem(alert: WeatherAlert, timestamp: Date): Weath
 
 	return {
 		id: `weather-alert-${alert.id}`,
+		sourceId,
 		type: WeatherFeedItemType.Alert,
 		timestamp,
 		data: {