feat: add generic CalDAV calendar data source

Add @aris/source-caldav package that fetches calendar events from any
CalDAV server via tsdav + ical.js.

- Supports Basic auth and OAuth via explicit authMethod discriminant
- serverUrl provided at construction time, not hardcoded
- Optional timeZone for correct local day boundaries
- Credentials cleared from memory after client login
- Failed calendar fetches logged, not silently dropped
- Login promise cached with retry on failure

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

bun.lock

@@ -89,6 +89,15 @@
         "arktype": "^2.1.0",
       },
     },
+    "packages/aris-source-caldav": {
+      "name": "@aris/source-caldav",
+      "version": "0.0.0",
+      "dependencies": {
+        "@aris/core": "workspace:*",
+        "ical.js": "^2.1.0",
+        "tsdav": "^2.1.7",
+      },
+    },
     "packages/aris-source-google-calendar": {
       "name": "@aris/source-google-calendar",
       "version": "0.0.0",
@@ -135,6 +144,8 @@
 
     "@aris/data-source-weatherkit": ["@aris/data-source-weatherkit@workspace:packages/aris-data-source-weatherkit"],
 
+    "@aris/source-caldav": ["@aris/source-caldav@workspace:packages/aris-source-caldav"],
+
     "@aris/source-google-calendar": ["@aris/source-google-calendar@workspace:packages/aris-source-google-calendar"],
 
     "@aris/source-location": ["@aris/source-location@workspace:packages/aris-source-location"],
@@ -899,6 +910,8 @@
 
     "bare-events": ["bare-events@2.8.2", "", { "peerDependencies": { "bare-abort-controller": "*" }, "optionalPeers": ["bare-abort-controller"] }, "sha512-riJjyv1/mHLIPX4RwiK+oW9/4c3TEUeORHKefKAKnZ5kyslbN+HXowtbaVEqt4IMUB7OXlfixcs6gsFeo/jhiQ=="],
 
+    "base-64": ["base-64@1.0.0", "", {}, "sha512-kwDPIFCGx0NZHog36dj+tHiwP4QMzsZ3AgMViUBKI0+V5n4U0ufTCUMhnQ04diaRI8EX/QcPfql7zlhZ7j4zgg=="],
+
     "base64-js": ["base64-js@1.5.1", "", {}, "sha512-AKpaYlHn8t4SVbOHCy+b5+KKgvR4vrsD8vbvrbiQJps7fKDTkjkDry6ji0rUJjC0kzbNePLwzxq8iypo41qeWA=="],
 
     "baseline-browser-mapping": ["baseline-browser-mapping@2.9.19", "", { "bin": { "baseline-browser-mapping": "dist/cli.js" } }, "sha512-ipDqC8FrAl/76p2SSWKSI+H9tFwm7vYqXQrItCuiVPt26Km0jS+NzSsBWAaBusvSbQcfJG+JitdMm+wZAgTYqg=="],
@@ -1011,7 +1024,7 @@
 
     "create-require": ["create-require@1.1.1", "", {}, "sha512-dcKFX3jn0MpIaXjisoRvexIJVEKzaq7z2rZKxf+MSr9TkdmHmsU4m2lcLojrj/FHl8mk5VxMmYA+ftRkP/3oKQ=="],
 
-    "cross-fetch": ["cross-fetch@3.2.0", "", { "dependencies": { "node-fetch": "^2.7.0" } }, "sha512-Q+xVJLoGOeIMXZmbUK4HYk+69cQH6LudR0Vu/pRm2YlU/hDV9CiS0gKUMaWY5f2NeUH9C1nV3bsTlCo0FsTV1Q=="],
+    "cross-fetch": ["cross-fetch@4.1.0", "", { "dependencies": { "node-fetch": "^2.7.0" } }, "sha512-uKm5PU+MHTootlWEY+mZ4vvXoCn4fLQxT9dSc1sXVMSFkINTJVN8cAQROpwcKm8bJ/c7rgZVIBWzH5T78sNZZw=="],
 
     "cross-spawn": ["cross-spawn@7.0.6", "", { "dependencies": { "path-key": "^3.1.0", "shebang-command": "^2.0.0", "which": "^2.0.1" } }, "sha512-uV2QOWP2nWzsy2aMp8aRibhi9dlzF5Hgh5SHaB9OiTGEyDTiJJyx0uy51QXdyWbtAHNua4XJzUKca3OzKUd3vA=="],
 
@@ -1389,6 +1402,8 @@
 
     "hyphenate-style-name": ["hyphenate-style-name@1.1.0", "", {}, "sha512-WDC/ui2VVRrz3jOVi+XtjqkDjiVjTtFaAGiW37k6b+ohyQ5wYDOGkvCZa8+H0nx3gyvv0+BST9xuOgIyGQ00gw=="],
 
+    "ical.js": ["ical.js@2.2.1", "", {}, "sha512-yK/UlPbEs316igb/tjRgbFA8ZV75rCsBJp/hWOatpyaPNlgw0dGDmU+FoicOcwX4xXkeXOkYiOmCqNPFpNPkQg=="],
+
     "ieee754": ["ieee754@1.2.1", "", {}, "sha512-dcyqhDvX1C46lXZcVqCpK+FtMRQVdIMN6/Df5js2zouUsqG7I6sFxitIC+7KYK29KdXOLHdu9zL4sFnoVQnqaA=="],
 
     "ignore": ["ignore@5.3.0", "", {}, "sha512-g7dmpshy+gD7mh88OC9NwSGTKoc3kyLAZQRU1mt53Aw/vnvfXnbC+F/7F7QoYVKbV+KNvJx8wArewKy1vXMtlg=="],
@@ -2163,6 +2178,8 @@
 
     "tsconfig-paths": ["tsconfig-paths@3.15.0", "", { "dependencies": { "@types/json5": "^0.0.29", "json5": "^1.0.2", "minimist": "^1.2.6", "strip-bom": "^3.0.0" } }, "sha512-2Ac2RgzDe/cn48GvOe3M+o82pEFewD3UPbyoUHHdKasHwJKjds4fLXWf/Ux5kATBKN20oaFGu+jbElp1pos0mg=="],
 
+    "tsdav": ["tsdav@2.1.8", "", { "dependencies": { "base-64": "1.0.0", "cross-fetch": "4.1.0", "debug": "4.4.3", "xml-js": "1.6.11" } }, "sha512-zvQvhZLzTaEmNNgJbBlUYT/JOq9Xpw/xkxCqs7IT2d2/7o7pss0iZOlZXuHJ5VcvSvTny42Vc6+6GyzZcrCJ1g=="],
+
     "tslib": ["tslib@2.6.2", "", {}, "sha512-AEYxH93jGFPn/a2iVAwW87VuUIkR1FVUKB77NwMF7nBTDkDrrT/Hpt/IrCJ0QXhW27jTBDcf5ZY7w6RiqTMw2Q=="],
 
     "tunnel-agent": ["tunnel-agent@0.6.0", "", { "dependencies": { "safe-buffer": "^5.0.1" } }, "sha512-McnNiV1l8RYeY8tBgEpuodCC1mLUdbSN+CYBL7kJsJNInOP8UjDDEwdk6Mw60vdLLrr5NHKZhMAOSrR2NZuQ+w=="],
@@ -2285,6 +2302,8 @@
 
     "xcode": ["xcode@3.0.1", "", { "dependencies": { "simple-plist": "^1.1.0", "uuid": "^7.0.3" } }, "sha512-kCz5k7J7XbJtjABOvkc5lJmkiDh8VhjVCGNiqdKCscmVpdVUpEAyXv1xmCLkQJ5dsHqx3IPO4XW+NTDhU/fatA=="],
 
+    "xml-js": ["xml-js@1.6.11", "", { "dependencies": { "sax": "^1.2.4" }, "bin": { "xml-js": "./bin/cli.js" } }, "sha512-7rVi2KMfwfWFl+GpPg6m80IVMWXLRjO+PxTq7V2CDhoGak0wzYzFgUY2m4XJ47OGdXd8eLE8EmwfAmdjw7lC1g=="],
+
     "xml2js": ["xml2js@0.6.0", "", { "dependencies": { "sax": ">=0.6.0", "xmlbuilder": "~11.0.0" } }, "sha512-eLTh0kA8uHceqesPqSE+VvO1CDDJWMwlQfB6LuN6T8w6MaDJ8Txm8P7s5cHD0miF0V+GGTZrDQfxPZQVsur33w=="],
 
     "xmlbuilder": ["xmlbuilder@14.0.0", "", {}, "sha512-ts+B2rSe4fIckR6iquDjsKbQFK2NlUk6iG5nf14mDEyldgoc2nEKZ3jZWMPTxGQwVgToSjt6VGIho1H8/fNFTg=="],
@@ -2613,6 +2632,8 @@
 
     "fast-glob/glob-parent": ["glob-parent@5.1.2", "", { "dependencies": { "is-glob": "^4.0.1" } }, "sha512-AOIgSQCepiJYwP3ARnGx+5VnTu2HBYdzbGP45eLw1vr3zB3vZLeyed1sC9hnbcOc9/SrMyM5RPQrkGz4aS9Zow=="],
 
+    "fbjs/cross-fetch": ["cross-fetch@3.2.0", "", { "dependencies": { "node-fetch": "^2.7.0" } }, "sha512-Q+xVJLoGOeIMXZmbUK4HYk+69cQH6LudR0Vu/pRm2YlU/hDV9CiS0gKUMaWY5f2NeUH9C1nV3bsTlCo0FsTV1Q=="],
+
     "fbjs/promise": ["promise@7.3.1", "", { "dependencies": { "asap": "~2.0.3" } }, "sha512-nolQXZ/4L+bP/UGlkfaIujX9BKxGwmQ9OT4mOt5yvy8iK1h3wqTEJCijzGANTCCl9nWjY41juyAn2K3Q1hLLTg=="],
 
     "figures/escape-string-regexp": ["escape-string-regexp@1.0.5", "", {}, "sha512-vbRorB5FUQWvla16U8R/qgaFIya2qGzwDrNmCZuYKrbdSUMG6I1ZCGQRefkRVhuOkIGVne7BQ35DSfo1qvJqFg=="],
@@ -2939,6 +2960,8 @@
 
     "expo/@expo/config-plugins/semver": ["semver@7.7.2", "", { "bin": { "semver": "bin/semver.js" } }, "sha512-RF0Fw+rO5AMf9MAyaRXI4AV0Ulj5lMHqVxxdSgiVbixSCXoEmmX/jk0CuJw4+3SqroYO9VoUh+HcuJivvtJemA=="],
 
+    "fbjs/cross-fetch/node-fetch": ["node-fetch@2.7.0", "", { "dependencies": { "whatwg-url": "^5.0.0" }, "peerDependencies": { "encoding": "^0.1.0" }, "optionalPeers": ["encoding"] }, "sha512-c4FRfUm/dbcWZ7U+1Wq0AwCyFL+3nt2bEw05wfxSz+DWpWsitgmSgYmy2dQdWyKC1694ELPqMs/YzUSNozLt8A=="],
+
     "finalhandler/debug/ms": ["ms@2.0.0", "", {}, "sha512-Tpp60P6IUJDTuOq/5Z8cdskzJujfwqfOTkrwIwj7IRISpnkJnT6SyJ4PCPnGMoFjC9ddhal5KVIYtAt97ix05A=="],
 
     "glob/minimatch/brace-expansion": ["brace-expansion@1.1.12", "", { "dependencies": { "balanced-match": "^1.0.0", "concat-map": "0.0.1" } }, "sha512-9T9UjW3r0UW5c1Q7GTwllptXwhvYmEzFhzMfZ9H7FQWt+uZePjZPjBP/W1ZEyZ1twGWom5/56TF4lPcqjnDHcg=="],

packages/aris-source-caldav/README.md

@@ -0,0 +1,58 @@
+# @aris/source-caldav
+
+A FeedSource that fetches calendar events from any CalDAV server.
+
+## Usage
+
+```ts
+import { CalDavSource } from "@aris/source-caldav"
+
+// Basic auth (Nextcloud, Radicale, Baikal, iCloud, etc.)
+const source = new CalDavSource({
+	serverUrl: "https://caldav.example.com",
+	authMethod: "basic",
+	username: "user",
+	password: "pass",
+	lookAheadDays: 7, // optional, default: 0 (today only)
+	timeZone: "America/New_York", // optional, default: UTC
+})
+
+// OAuth
+const source = new CalDavSource({
+	serverUrl: "https://caldav.provider.com",
+	authMethod: "oauth",
+	accessToken: "...",
+	refreshToken: "...",
+	tokenUrl: "https://provider.com/oauth/token",
+})
+```
+
+### iCloud
+
+Use your Apple ID email as the username and an [app-specific password](https://support.apple.com/en-us/102654):
+
+```ts
+const source = new CalDavSource({
+	serverUrl: "https://caldav.icloud.com",
+	authMethod: "basic",
+	username: "you@icloud.com",
+	password: "<app-specific-password>",
+})
+```
+
+## Testing
+
+```bash
+bun test
+```
+
+### Live test
+
+`bun run test:live` connects to a real CalDAV server and prints all events to the console. It prompts for:
+
+- **CalDAV server URL** — e.g. `https://caldav.icloud.com`
+- **Username** — your account email
+- **Password** — your password (or app-specific password for iCloud)
+- **Look-ahead days** — how many days beyond today to fetch (default: 0)
+
+The script runs both `fetchContext` and `fetchItems`, printing the calendar context (in-progress events, next event, today's count) followed by each event with its title, time, location, signals, and attendees.

packages/aris-source-caldav/fixtures/all-day-event.ics

@@ -0,0 +1,11 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Test//Test//EN
+BEGIN:VEVENT
+UID:all-day-001@test
+DTSTART;VALUE=DATE:20260115
+DTEND;VALUE=DATE:20260116
+SUMMARY:Company Holiday
+STATUS:CONFIRMED
+END:VEVENT
+END:VCALENDAR

packages/aris-source-caldav/fixtures/cancelled-event.ics

@@ -0,0 +1,11 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Test//Test//EN
+BEGIN:VEVENT
+UID:cancelled-001@test
+DTSTART:20260115T120000Z
+DTEND:20260115T130000Z
+SUMMARY:Cancelled Meeting
+STATUS:CANCELLED
+END:VEVENT
+END:VCALENDAR

packages/aris-source-caldav/fixtures/minimal-event.ics

@@ -0,0 +1,10 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Test//Test//EN
+BEGIN:VEVENT
+UID:minimal-001@test
+DTSTART:20260115T180000Z
+DTEND:20260115T190000Z
+SUMMARY:Quick Chat
+END:VEVENT
+END:VCALENDAR

packages/aris-source-caldav/fixtures/recurring-event.ics

@@ -0,0 +1,20 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Test//Test//EN
+BEGIN:VEVENT
+UID:recurring-001@test
+DTSTART:20260115T090000Z
+DTEND:20260115T093000Z
+SUMMARY:Weekly Sync
+RRULE:FREQ=WEEKLY;COUNT=4
+STATUS:CONFIRMED
+END:VEVENT
+BEGIN:VEVENT
+UID:recurring-001@test
+RECURRENCE-ID:20260122T090000Z
+DTSTART:20260122T100000Z
+DTEND:20260122T103000Z
+SUMMARY:Weekly Sync (moved)
+STATUS:CONFIRMED
+END:VEVENT
+END:VCALENDAR

packages/aris-source-caldav/fixtures/single-event.ics

@@ -0,0 +1,26 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Test//Test//EN
+BEGIN:VEVENT
+UID:single-event-001@test
+DTSTART:20260115T140000Z
+DTEND:20260115T150000Z
+SUMMARY:Team Standup
+LOCATION:Conference Room A
+DESCRIPTION:Daily standup meeting
+STATUS:CONFIRMED
+URL:https://example.com/meeting/123
+ORGANIZER;CN=Alice Smith:mailto:alice@example.com
+ATTENDEE;CN=Bob Jones;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED:mailto:bob@example.com
+ATTENDEE;CN=Carol White;ROLE=OPT-PARTICIPANT;PARTSTAT=TENTATIVE:mailto:carol@example.com
+BEGIN:VALARM
+TRIGGER:-PT15M
+ACTION:DISPLAY
+DESCRIPTION:Reminder
+END:VALARM
+BEGIN:VALARM
+TRIGGER:-PT5M
+ACTION:AUDIO
+END:VALARM
+END:VEVENT
+END:VCALENDAR

packages/aris-source-caldav/package.json

@@ -0,0 +1,16 @@
+{
+	"name": "@aris/source-caldav",
+	"version": "0.0.0",
+	"type": "module",
+	"main": "src/index.ts",
+	"types": "src/index.ts",
+	"scripts": {
+		"test": "bun test .",
+		"test:live": "bun run scripts/test-live.ts"
+	},
+	"dependencies": {
+		"@aris/core": "workspace:*",
+		"ical.js": "^2.1.0",
+		"tsdav": "^2.1.7"
+	}
+}

packages/aris-source-caldav/scripts/test-live.ts

@@ -0,0 +1,62 @@
+/**
+ * Live test script for CalDavSource.
+ *
+ * Usage:
+ *   bun run test-live.ts
+ */
+
+import { CalDavSource } from "../src/index.ts"
+
+const serverUrl = prompt("CalDAV server URL:")
+const username = prompt("Username:")
+const password = prompt("Password:")
+const lookAheadRaw = prompt("Look-ahead days (default 0):")
+
+if (!serverUrl || !username || !password) {
+	console.error("Server URL, username, and password are required.")
+	process.exit(1)
+}
+
+const lookAheadDays = Number(lookAheadRaw) || 0
+
+const source = new CalDavSource({
+	serverUrl,
+	authMethod: "basic",
+	username,
+	password,
+	lookAheadDays,
+})
+
+const context = { time: new Date() }
+
+console.log(`\nFetching from ${serverUrl} as ${username} (lookAheadDays=${lookAheadDays})...\n`)
+
+const contextResult = await source.fetchContext(context)
+const items = await source.fetchItems(context)
+
+console.log("=== Context ===")
+console.log(JSON.stringify(contextResult, null, 2))
+
+console.log(`\n=== Feed Items (${items.length}) ===`)
+for (const item of items) {
+	console.log(`\n--- ${item.data.title} ---`)
+	console.log(`  ID:         ${item.id}`)
+	console.log(`  Calendar:   ${item.data.calendarName ?? "(unknown)"}`)
+	console.log(`  Start:      ${item.data.startDate.toISOString()}`)
+	console.log(`  End:        ${item.data.endDate.toISOString()}`)
+	console.log(`  All-day:    ${item.data.isAllDay}`)
+	console.log(`  Location:   ${item.data.location ?? "(none)"}`)
+	console.log(`  Status:     ${item.data.status ?? "(none)"}`)
+	console.log(`  Urgency:    ${item.signals?.urgency}`)
+	console.log(`  Relevance:  ${item.signals?.timeRelevance}`)
+	if (item.data.attendees.length > 0) {
+		console.log(`  Attendees:  ${item.data.attendees.map((a) => a.name ?? a.email).join(", ")}`)
+	}
+	if (item.data.description) {
+		console.log(`  Desc:       ${item.data.description.slice(0, 100)}`)
+	}
+}
+
+if (items.length === 0) {
+	console.log("(no events found in the time window)")
+}

packages/aris-source-caldav/src/caldav-source.test.ts

@@ -0,0 +1,482 @@
+import type { Context } from "@aris/core"
+
+import { TimeRelevance, contextValue } from "@aris/core"
+import { describe, expect, test } from "bun:test"
+import { readFileSync } from "node:fs"
+import { join } from "node:path"
+
+import type {
+	CalDavDAVCalendar,
+	CalDavDAVClient,
+	CalDavDAVObject,
+	CalDavEventData,
+} from "./types.ts"
+
+import { CalDavSource, computeSignals } from "./caldav-source.ts"
+import { CalDavCalendarKey } from "./calendar-context.ts"
+
+function loadFixture(name: string): string {
+	return readFileSync(join(import.meta.dir, "..", "fixtures", name), "utf-8")
+}
+
+function createContext(time: Date): Context {
+	return { time }
+}
+
+class MockDAVClient implements CalDavDAVClient {
+	credentials: Record<string, unknown> = {}
+	fetchCalendarsCallCount = 0
+	lastTimeRange: { start: string; end: string } | null = null
+	private calendars: CalDavDAVCalendar[]
+	private objectsByCalendarUrl: Record<string, CalDavDAVObject[]>
+
+	constructor(
+		calendars: CalDavDAVCalendar[],
+		objectsByCalendarUrl: Record<string, CalDavDAVObject[]>,
+	) {
+		this.calendars = calendars
+		this.objectsByCalendarUrl = objectsByCalendarUrl
+	}
+
+	async login(): Promise<void> {}
+
+	async fetchCalendars(): Promise<CalDavDAVCalendar[]> {
+		this.fetchCalendarsCallCount++
+		return this.calendars
+	}
+
+	async fetchCalendarObjects(params: {
+		calendar: CalDavDAVCalendar
+		timeRange: { start: string; end: string }
+	}): Promise<CalDavDAVObject[]> {
+		this.lastTimeRange = params.timeRange
+		return this.objectsByCalendarUrl[params.calendar.url] ?? []
+	}
+}
+
+function createSource(client: MockDAVClient, lookAheadDays?: number): CalDavSource {
+	return new CalDavSource({
+		serverUrl: "https://caldav.example.com",
+		authMethod: "basic",
+		username: "user",
+		password: "pass",
+		davClient: client,
+		lookAheadDays,
+	})
+}
+
+describe("CalDavSource", () => {
+	test("has correct id", () => {
+		const client = new MockDAVClient([], {})
+		const source = createSource(client)
+		expect(source.id).toBe("aris.caldav")
+	})
+
+	test("returns empty array when no calendars exist", async () => {
+		const client = new MockDAVClient([], {})
+		const source = createSource(client)
+		const items = await source.fetchItems(createContext(new Date("2026-01-15T12:00:00Z")))
+		expect(items).toEqual([])
+	})
+
+	test("returns feed items from a single calendar", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") }],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		const items = await source.fetchItems(createContext(new Date("2026-01-15T12:00:00Z")))
+
+		expect(items).toHaveLength(1)
+		expect(items[0]!.type).toBe("caldav-event")
+		expect(items[0]!.id).toBe("caldav-event-single-event-001@test")
+		expect(items[0]!.data.title).toBe("Team Standup")
+		expect(items[0]!.data.location).toBe("Conference Room A")
+		expect(items[0]!.data.calendarName).toBe("Work")
+		expect(items[0]!.data.attendees).toHaveLength(2)
+		expect(items[0]!.data.alarms).toHaveLength(2)
+	})
+
+	test("returns feed items from multiple calendars", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") }],
+			"/cal/personal": [
+				{
+					url: "/cal/personal/event2.ics",
+					data: loadFixture("all-day-event.ics"),
+				},
+			],
+		}
+		const client = new MockDAVClient(
+			[
+				{ url: "/cal/work", displayName: "Work" },
+				{ url: "/cal/personal", displayName: "Personal" },
+			],
+			objects,
+		)
+		const source = createSource(client)
+
+		const items = await source.fetchItems(createContext(new Date("2026-01-15T12:00:00Z")))
+
+		expect(items).toHaveLength(2)
+
+		const standup = items.find((i) => i.data.title === "Team Standup")
+		const holiday = items.find((i) => i.data.title === "Company Holiday")
+
+		expect(standup).toBeDefined()
+		expect(standup!.data.calendarName).toBe("Work")
+
+		expect(holiday).toBeDefined()
+		expect(holiday!.data.calendarName).toBe("Personal")
+		expect(holiday!.data.isAllDay).toBe(true)
+	})
+
+	test("skips objects with non-string data", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [
+				{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") },
+				{ url: "/cal/work/bad.ics", data: 12345 },
+				{ url: "/cal/work/empty.ics" },
+			],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		const items = await source.fetchItems(createContext(new Date("2026-01-15T12:00:00Z")))
+		expect(items).toHaveLength(1)
+		expect(items[0]!.data.title).toBe("Team Standup")
+	})
+
+	test("uses context time as feed item timestamp", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") }],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		const now = new Date("2026-01-15T12:00:00Z")
+		const items = await source.fetchItems(createContext(now))
+		expect(items[0]!.timestamp).toEqual(now)
+	})
+
+	test("assigns signals based on event proximity", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [
+				{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") },
+				{ url: "/cal/work/allday.ics", data: loadFixture("all-day-event.ics") },
+			],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		// 2 hours before the event at 14:00
+		const items = await source.fetchItems(createContext(new Date("2026-01-15T12:00:00Z")))
+
+		const standup = items.find((i) => i.data.title === "Team Standup")
+		const holiday = items.find((i) => i.data.title === "Company Holiday")
+
+		expect(standup!.signals!.urgency).toBe(0.7) // within 2 hours
+		expect(standup!.signals!.timeRelevance).toBe(TimeRelevance.Upcoming)
+		expect(holiday!.signals!.urgency).toBe(0.3) // all-day
+		expect(holiday!.signals!.timeRelevance).toBe(TimeRelevance.Ambient)
+	})
+
+	test("handles calendar with non-string displayName", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/weird": [
+				{
+					url: "/cal/weird/event1.ics",
+					data: loadFixture("minimal-event.ics"),
+				},
+			],
+		}
+		const client = new MockDAVClient(
+			[{ url: "/cal/weird", displayName: { _cdata: "Weird Calendar" } }],
+			objects,
+		)
+		const source = createSource(client)
+
+		const items = await source.fetchItems(createContext(new Date("2026-01-15T12:00:00Z")))
+		expect(items[0]!.data.calendarName).toBeNull()
+	})
+
+	test("handles recurring events with exceptions", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [
+				{
+					url: "/cal/work/recurring.ics",
+					data: loadFixture("recurring-event.ics"),
+				},
+			],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		const items = await source.fetchItems(createContext(new Date("2026-01-15T08:00:00Z")))
+
+		expect(items).toHaveLength(2)
+
+		const base = items.find((i) => i.data.title === "Weekly Sync")
+		const exception = items.find((i) => i.data.title === "Weekly Sync (moved)")
+
+		expect(base).toBeDefined()
+		expect(base!.data.recurrenceId).toBeNull()
+
+		expect(exception).toBeDefined()
+		expect(exception!.data.recurrenceId).not.toBeNull()
+		expect(exception!.id).toContain("-")
+	})
+
+	test("caches events within the same refresh cycle", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") }],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		const context = createContext(new Date("2026-01-15T12:00:00Z"))
+
+		await source.fetchContext(context)
+		await source.fetchItems(context)
+
+		// Same context.time reference — fetchEvents should only hit the client once
+		expect(client.fetchCalendarsCallCount).toBe(1)
+	})
+
+	test("uses timezone for time range when provided", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") }],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+
+		// 2026-01-15T22:00:00Z = 2026-01-16T09:00:00 in Australia/Sydney (AEDT, UTC+11)
+		const source = new CalDavSource({
+			serverUrl: "https://caldav.example.com",
+			authMethod: "basic",
+			username: "user",
+			password: "pass",
+			davClient: client,
+			timeZone: "Australia/Sydney",
+		})
+
+		await source.fetchItems(createContext(new Date("2026-01-15T22:00:00Z")))
+
+		// "Today" in Sydney is Jan 16, so start should be Jan 15 13:00 UTC (midnight Jan 16 AEDT)
+		expect(client.lastTimeRange).not.toBeNull()
+		expect(client.lastTimeRange!.start).toBe("2026-01-15T13:00:00.000Z")
+		// End should be Jan 16 13:00 UTC (midnight Jan 17 AEDT) — 1 day window
+		expect(client.lastTimeRange!.end).toBe("2026-01-16T13:00:00.000Z")
+	})
+
+	test("defaults to UTC midnight when no timezone provided", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") }],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		await source.fetchItems(createContext(new Date("2026-01-15T22:00:00Z")))
+
+		expect(client.lastTimeRange).not.toBeNull()
+		expect(client.lastTimeRange!.start).toBe("2026-01-15T00:00:00.000Z")
+		expect(client.lastTimeRange!.end).toBe("2026-01-16T00:00:00.000Z")
+	})
+
+	test("refetches events for a different context time", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") }],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		await source.fetchItems(createContext(new Date("2026-01-15T12:00:00Z")))
+		await source.fetchItems(createContext(new Date("2026-01-15T13:00:00Z")))
+
+		// Different context.time references — should fetch twice
+		expect(client.fetchCalendarsCallCount).toBe(2)
+	})
+})
+
+describe("CalDavSource.fetchContext", () => {
+	test("returns empty context when no calendars exist", async () => {
+		const client = new MockDAVClient([], {})
+		const source = createSource(client)
+		const ctx = await source.fetchContext(createContext(new Date("2026-01-15T12:00:00Z")))
+		const calendar = contextValue(ctx as Context, CalDavCalendarKey)
+
+		expect(calendar).toBeDefined()
+		expect(calendar!.inProgress).toEqual([])
+		expect(calendar!.nextEvent).toBeNull()
+		expect(calendar!.hasTodayEvents).toBe(false)
+		expect(calendar!.todayEventCount).toBe(0)
+	})
+
+	test("identifies in-progress events", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") }],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		// 14:30 is during the 14:00-15:00 event
+		const ctx = await source.fetchContext(createContext(new Date("2026-01-15T14:30:00Z")))
+		const calendar = contextValue(ctx as Context, CalDavCalendarKey)
+
+		expect(calendar!.inProgress).toHaveLength(1)
+		expect(calendar!.inProgress[0]!.title).toBe("Team Standup")
+	})
+
+	test("identifies next upcoming event", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") }],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		// 12:00 is before the 14:00 event
+		const ctx = await source.fetchContext(createContext(new Date("2026-01-15T12:00:00Z")))
+		const calendar = contextValue(ctx as Context, CalDavCalendarKey)
+
+		expect(calendar!.inProgress).toHaveLength(0)
+		expect(calendar!.nextEvent).not.toBeNull()
+		expect(calendar!.nextEvent!.title).toBe("Team Standup")
+	})
+
+	test("excludes all-day events from inProgress and nextEvent", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [{ url: "/cal/work/allday.ics", data: loadFixture("all-day-event.ics") }],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		const ctx = await source.fetchContext(createContext(new Date("2026-01-15T12:00:00Z")))
+		const calendar = contextValue(ctx as Context, CalDavCalendarKey)
+
+		expect(calendar!.inProgress).toHaveLength(0)
+		expect(calendar!.nextEvent).toBeNull()
+		expect(calendar!.hasTodayEvents).toBe(true)
+		expect(calendar!.todayEventCount).toBe(1)
+	})
+
+	test("counts all events including all-day in todayEventCount", async () => {
+		const objects: Record<string, CalDavDAVObject[]> = {
+			"/cal/work": [
+				{ url: "/cal/work/event1.ics", data: loadFixture("single-event.ics") },
+				{ url: "/cal/work/allday.ics", data: loadFixture("all-day-event.ics") },
+			],
+		}
+		const client = new MockDAVClient([{ url: "/cal/work", displayName: "Work" }], objects)
+		const source = createSource(client)
+
+		const ctx = await source.fetchContext(createContext(new Date("2026-01-15T12:00:00Z")))
+		const calendar = contextValue(ctx as Context, CalDavCalendarKey)
+
+		expect(calendar!.todayEventCount).toBe(2)
+		expect(calendar!.hasTodayEvents).toBe(true)
+	})
+})
+
+describe("computeSignals", () => {
+	const now = new Date("2026-01-15T12:00:00Z")
+
+	function makeEvent(overrides: Partial<CalDavEventData>): CalDavEventData {
+		return {
+			uid: "test-uid",
+			title: "Test",
+			startDate: new Date("2026-01-15T14:00:00Z"),
+			endDate: new Date("2026-01-15T15:00:00Z"),
+			isAllDay: false,
+			location: null,
+			description: null,
+			calendarName: null,
+			status: null,
+			url: null,
+			organizer: null,
+			attendees: [],
+			alarms: [],
+			recurrenceId: null,
+			...overrides,
+		}
+	}
+
+	test("all-day events get urgency 0.3 and ambient relevance", () => {
+		const event = makeEvent({ isAllDay: true })
+		const signals = computeSignals(event, now)
+		expect(signals.urgency).toBe(0.3)
+		expect(signals.timeRelevance).toBe(TimeRelevance.Ambient)
+	})
+
+	test("events starting within 30 minutes get urgency 0.9 and imminent relevance", () => {
+		const event = makeEvent({
+			startDate: new Date("2026-01-15T12:20:00Z"),
+		})
+		const signals = computeSignals(event, now)
+		expect(signals.urgency).toBe(0.9)
+		expect(signals.timeRelevance).toBe(TimeRelevance.Imminent)
+	})
+
+	test("events starting exactly at 30 minutes get urgency 0.9", () => {
+		const event = makeEvent({
+			startDate: new Date("2026-01-15T12:30:00Z"),
+		})
+		expect(computeSignals(event, now).urgency).toBe(0.9)
+	})
+
+	test("events starting within 2 hours get urgency 0.7 and upcoming relevance", () => {
+		const event = makeEvent({
+			startDate: new Date("2026-01-15T13:00:00Z"),
+		})
+		const signals = computeSignals(event, now)
+		expect(signals.urgency).toBe(0.7)
+		expect(signals.timeRelevance).toBe(TimeRelevance.Upcoming)
+	})
+
+	test("events later today get urgency 0.5", () => {
+		const event = makeEvent({
+			startDate: new Date("2026-01-15T20:00:00Z"),
+		})
+		expect(computeSignals(event, now).urgency).toBe(0.5)
+	})
+
+	test("in-progress events get urgency 0.8 and imminent relevance", () => {
+		const event = makeEvent({
+			startDate: new Date("2026-01-15T11:00:00Z"),
+			endDate: new Date("2026-01-15T13:00:00Z"),
+		})
+		const signals = computeSignals(event, now)
+		expect(signals.urgency).toBe(0.8)
+		expect(signals.timeRelevance).toBe(TimeRelevance.Imminent)
+	})
+
+	test("fully past events get urgency 0.2 and ambient relevance", () => {
+		const event = makeEvent({
+			startDate: new Date("2026-01-15T09:00:00Z"),
+			endDate: new Date("2026-01-15T10:00:00Z"),
+		})
+		const signals = computeSignals(event, now)
+		expect(signals.urgency).toBe(0.2)
+		expect(signals.timeRelevance).toBe(TimeRelevance.Ambient)
+	})
+
+	test("events on future days get urgency 0.2", () => {
+		const event = makeEvent({
+			startDate: new Date("2026-01-16T10:00:00Z"),
+		})
+		expect(computeSignals(event, now).urgency).toBe(0.2)
+	})
+
+	test("urgency boundaries are correct", () => {
+		// 31 minutes from now should be 0.7 (within 2 hours, not within 30 min)
+		const event31min = makeEvent({
+			startDate: new Date("2026-01-15T12:31:00Z"),
+		})
+		expect(computeSignals(event31min, now).urgency).toBe(0.7)
+
+		// 2 hours 1 minute from now should be 0.5 (later today, not within 2 hours)
+		const event2h1m = makeEvent({
+			startDate: new Date("2026-01-15T14:01:00Z"),
+		})
+		expect(computeSignals(event2h1m, now).urgency).toBe(0.5)
+	})
+})

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

@@ -0,0 +1,323 @@
+import type { ActionDefinition, Context, FeedItemSignals, FeedSource } from "@aris/core"
+
+import { TimeRelevance, UnknownActionError } from "@aris/core"
+import { DAVClient } from "tsdav"
+
+import type { CalDavDAVClient, CalDavEventData, CalDavFeedItem } from "./types.ts"
+
+import { CalDavCalendarKey, type CalendarContext } from "./calendar-context.ts"
+import { parseICalEvents } from "./ical-parser.ts"
+
+// -- Source options --
+
+interface CalDavSourceBaseOptions {
+	serverUrl: string
+	/** Number of additional days beyond today to fetch. Default: 0 (today only). */
+	lookAheadDays?: number
+	/** IANA timezone for determining "today" (e.g. "America/New_York"). Default: UTC. */
+	timeZone?: string
+	/** Optional DAV client for testing. */
+	davClient?: CalDavDAVClient
+}
+
+interface CalDavSourceBasicAuthOptions extends CalDavSourceBaseOptions {
+	authMethod: "basic"
+	username: string
+	password: string
+}
+
+interface CalDavSourceOAuthOptions extends CalDavSourceBaseOptions {
+	authMethod: "oauth"
+	accessToken: string
+	refreshToken: string
+	tokenUrl: string
+	expiration?: number
+	clientId?: string
+	clientSecret?: string
+}
+
+export type CalDavSourceOptions = CalDavSourceBasicAuthOptions | CalDavSourceOAuthOptions
+
+const DEFAULT_LOOK_AHEAD_DAYS = 0
+
+/**
+ * A FeedSource that fetches calendar events from any CalDAV server.
+ *
+ * Supports Basic auth (username/password) and OAuth (access token + refresh token).
+ * The server URL is provided at construction time.
+ *
+ * @example
+ * ```ts
+ * // Basic auth (self-hosted servers)
+ * const source = new CalDavSource({
+ *   serverUrl: "https://nextcloud.example.com/remote.php/dav",
+ *   authMethod: "basic",
+ *   username: "user",
+ *   password: "pass",
+ * })
+ *
+ * // OAuth (cloud providers)
+ * const source = new CalDavSource({
+ *   serverUrl: "https://caldav.provider.com",
+ *   authMethod: "oauth",
+ *   accessToken: "...",
+ *   refreshToken: "...",
+ *   tokenUrl: "https://provider.com/oauth/token",
+ * })
+ * ```
+ */
+export class CalDavSource implements FeedSource<CalDavFeedItem> {
+	readonly id = "aris.caldav"
+
+	private options: CalDavSourceOptions | null
+	private readonly lookAheadDays: number
+	private readonly timeZone: string | undefined
+	private readonly injectedClient: CalDavDAVClient | null
+	private clientPromise: Promise<CalDavDAVClient> | null = null
+	private cachedEvents: { time: Date; events: CalDavEventData[] } | null = null
+
+	constructor(options: CalDavSourceOptions) {
+		this.options = options
+		this.lookAheadDays = options.lookAheadDays ?? DEFAULT_LOOK_AHEAD_DAYS
+		this.timeZone = options.timeZone
+		this.injectedClient = options.davClient ?? null
+	}
+
+	async listActions(): Promise<Record<string, ActionDefinition>> {
+		return {}
+	}
+
+	async executeAction(actionId: string): Promise<void> {
+		throw new UnknownActionError(actionId)
+	}
+
+	async fetchContext(context: Context): Promise<Partial<Context> | null> {
+		const events = await this.fetchEvents(context)
+		if (events.length === 0) {
+			return {
+				[CalDavCalendarKey]: {
+					inProgress: [],
+					nextEvent: null,
+					hasTodayEvents: false,
+					todayEventCount: 0,
+				},
+			}
+		}
+
+		const now = context.time
+		const inProgress = events.filter((e) => !e.isAllDay && e.startDate <= now && e.endDate > now)
+
+		const upcoming = events
+			.filter((e) => !e.isAllDay && e.startDate > now)
+			.sort((a, b) => a.startDate.getTime() - b.startDate.getTime())
+
+		const calendarContext: CalendarContext = {
+			inProgress,
+			nextEvent: upcoming[0] ?? null,
+			hasTodayEvents: events.length > 0,
+			todayEventCount: events.length,
+		}
+
+		return { [CalDavCalendarKey]: calendarContext }
+	}
+
+	async fetchItems(context: Context): Promise<CalDavFeedItem[]> {
+		const now = context.time
+		const events = await this.fetchEvents(context)
+		return events.map((event) => createFeedItem(event, now))
+	}
+
+	private async fetchEvents(context: Context): Promise<CalDavEventData[]> {
+		if (this.cachedEvents && this.cachedEvents.time === context.time) {
+			return this.cachedEvents.events
+		}
+
+		const client = await this.connectClient()
+		const calendars = await client.fetchCalendars()
+
+		const { start, end } = computeTimeRange(context.time, this.lookAheadDays, this.timeZone)
+
+		const results = await Promise.allSettled(
+			calendars.map(async (calendar) => {
+				const objects = await client.fetchCalendarObjects({
+					calendar,
+					timeRange: {
+						start: start.toISOString(),
+						end: end.toISOString(),
+					},
+				})
+				// tsdav types displayName as string | Record<string, unknown> | undefined
+				const calendarName = typeof calendar.displayName === "string" ? calendar.displayName : null
+				return { objects, calendarName }
+			}),
+		)
+
+		const allEvents: CalDavEventData[] = []
+		for (const result of results) {
+			if (result.status === "rejected") {
+				console.warn("[aris.caldav] Failed to fetch calendar:", result.reason)
+				continue
+			}
+			const { objects, calendarName } = result.value
+			for (const obj of objects) {
+				if (typeof obj.data !== "string") continue
+
+				const events = parseICalEvents(obj.data, calendarName)
+				for (const event of events) {
+					allEvents.push(event)
+				}
+			}
+		}
+
+		this.cachedEvents = { time: context.time, events: allEvents }
+		return allEvents
+	}
+
+	private connectClient(): Promise<CalDavDAVClient> {
+		if (this.injectedClient) {
+			return Promise.resolve(this.injectedClient)
+		}
+
+		if (!this.clientPromise) {
+			this.clientPromise = this.createAndLoginClient().catch((err) => {
+				this.clientPromise = null
+				throw err
+			})
+		}
+
+		return this.clientPromise
+	}
+
+	private async createAndLoginClient(): Promise<CalDavDAVClient> {
+		const opts = this.options
+		if (!opts) {
+			throw new Error("CalDavSource options have already been consumed")
+		}
+
+		let client: CalDavDAVClient
+
+		if (opts.authMethod === "basic") {
+			client = new DAVClient({
+				serverUrl: opts.serverUrl,
+				credentials: {
+					username: opts.username,
+					password: opts.password,
+				},
+				authMethod: "Basic",
+				defaultAccountType: "caldav",
+			})
+		} else {
+			client = new DAVClient({
+				serverUrl: opts.serverUrl,
+				credentials: {
+					tokenUrl: opts.tokenUrl,
+					refreshToken: opts.refreshToken,
+					accessToken: opts.accessToken,
+					expiration: opts.expiration,
+					clientId: opts.clientId,
+					clientSecret: opts.clientSecret,
+				},
+				authMethod: "Oauth",
+				defaultAccountType: "caldav",
+			})
+		}
+
+		await client.login()
+		this.options = null
+		return client
+	}
+}
+
+function computeTimeRange(
+	now: Date,
+	lookAheadDays: number,
+	timeZone?: string,
+): { start: Date; end: Date } {
+	const start = startOfDay(now, timeZone)
+	const end = new Date(start.getTime() + (1 + lookAheadDays) * 24 * 60 * 60 * 1000)
+	return { start, end }
+}
+
+/**
+ * Returns midnight (start of day) as a UTC Date.
+ * When timeZone is provided, "midnight" is local midnight in that timezone
+ * converted to UTC. Otherwise, UTC midnight.
+ */
+function startOfDay(date: Date, timeZone?: string): Date {
+	if (!timeZone) {
+		const d = new Date(date)
+		d.setUTCHours(0, 0, 0, 0)
+		return d
+	}
+
+	// Extract the local year/month/day in the target timezone
+	const parts = new Intl.DateTimeFormat("en-CA", {
+		timeZone,
+		year: "numeric",
+		month: "2-digit",
+		day: "2-digit",
+	}).formatToParts(date)
+
+	const year = Number(parts.find((p) => p.type === "year")!.value)
+	const month = Number(parts.find((p) => p.type === "month")!.value)
+	const day = Number(parts.find((p) => p.type === "day")!.value)
+
+	// Binary-search-free approach: construct a UTC date at the local date's noon,
+	// then use the timezone offset at that moment to find local midnight in UTC.
+	const noonUtc = Date.UTC(year, month - 1, day, 12, 0, 0)
+	const noonLocal = new Date(noonUtc).toLocaleString("sv-SE", { timeZone, hour12: false })
+	// sv-SE locale formats as "YYYY-MM-DD HH:MM:SS" which Date can parse
+	const noonLocalMs = new Date(noonLocal + "Z").getTime()
+	const offsetMs = noonLocalMs - noonUtc
+
+	return new Date(Date.UTC(year, month - 1, day) - offsetMs)
+}
+
+export function computeSignals(event: CalDavEventData, now: Date): FeedItemSignals {
+	if (event.isAllDay) {
+		return { urgency: 0.3, timeRelevance: TimeRelevance.Ambient }
+	}
+
+	const msUntilStart = event.startDate.getTime() - now.getTime()
+
+	// Event already started
+	if (msUntilStart < 0) {
+		const isInProgress = now.getTime() < event.endDate.getTime()
+		return isInProgress
+			? { urgency: 0.8, timeRelevance: TimeRelevance.Imminent }
+			: { urgency: 0.2, timeRelevance: TimeRelevance.Ambient }
+	}
+
+	// Starting within 30 minutes
+	if (msUntilStart <= 30 * 60 * 1000) {
+		return { urgency: 0.9, timeRelevance: TimeRelevance.Imminent }
+	}
+
+	// Starting within 2 hours
+	if (msUntilStart <= 2 * 60 * 60 * 1000) {
+		return { urgency: 0.7, timeRelevance: TimeRelevance.Upcoming }
+	}
+
+	// Later today
+	const startOfDay = new Date(now)
+	startOfDay.setUTCHours(0, 0, 0, 0)
+	const endOfDay = new Date(startOfDay)
+	endOfDay.setUTCDate(endOfDay.getUTCDate() + 1)
+
+	if (event.startDate.getTime() < endOfDay.getTime()) {
+		return { urgency: 0.5, timeRelevance: TimeRelevance.Upcoming }
+	}
+
+	// Future days
+	return { urgency: 0.2, timeRelevance: TimeRelevance.Ambient }
+}
+
+function createFeedItem(event: CalDavEventData, now: Date): CalDavFeedItem {
+	return {
+		id: `caldav-event-${event.uid}${event.recurrenceId ? `-${event.recurrenceId}` : ""}`,
+		type: "caldav-event",
+		timestamp: now,
+		data: event,
+		signals: computeSignals(event, now),
+	}
+}

packages/aris-source-caldav/src/calendar-context.ts

@@ -0,0 +1,24 @@
+import type { ContextKey } from "@aris/core"
+
+import { contextKey } from "@aris/core"
+
+import type { CalDavEventData } from "./types.ts"
+
+/**
+ * Calendar context for downstream sources.
+ *
+ * Provides a snapshot of the user's upcoming CalDAV events so other sources
+ * can adapt (e.g. a commute source checking if there's a meeting soon).
+ */
+export interface CalendarContext {
+	/** Events happening right now */
+	inProgress: CalDavEventData[]
+	/** Next upcoming event, if any */
+	nextEvent: CalDavEventData | null
+	/** Whether the user has any events today */
+	hasTodayEvents: boolean
+	/** Total number of events today */
+	todayEventCount: number
+}
+
+export const CalDavCalendarKey: ContextKey<CalendarContext> = contextKey("caldavCalendar")

packages/aris-source-caldav/src/ical-parser.test.ts

@@ -0,0 +1,107 @@
+import { describe, expect, test } from "bun:test"
+import { readFileSync } from "node:fs"
+import { join } from "node:path"
+
+import { parseICalEvents } from "./ical-parser.ts"
+
+function loadFixture(name: string): string {
+	return readFileSync(join(import.meta.dir, "..", "fixtures", name), "utf-8")
+}
+
+describe("parseICalEvents", () => {
+	test("parses a full event with all fields", () => {
+		const events = parseICalEvents(loadFixture("single-event.ics"), "Work")
+
+		expect(events).toHaveLength(1)
+		const event = events[0]!
+
+		expect(event.uid).toBe("single-event-001@test")
+		expect(event.title).toBe("Team Standup")
+		expect(event.startDate).toEqual(new Date("2026-01-15T14:00:00Z"))
+		expect(event.endDate).toEqual(new Date("2026-01-15T15:00:00Z"))
+		expect(event.isAllDay).toBe(false)
+		expect(event.location).toBe("Conference Room A")
+		expect(event.description).toBe("Daily standup meeting")
+		expect(event.calendarName).toBe("Work")
+		expect(event.status).toBe("confirmed")
+		expect(event.url).toBe("https://example.com/meeting/123")
+		expect(event.organizer).toBe("Alice Smith")
+		expect(event.recurrenceId).toBeNull()
+
+		expect(event.attendees).toHaveLength(2)
+		expect(event.attendees[0]).toEqual({
+			name: "Bob Jones",
+			email: "bob@example.com",
+			role: "required",
+			status: "accepted",
+		})
+		expect(event.attendees[1]).toEqual({
+			name: "Carol White",
+			email: "carol@example.com",
+			role: "optional",
+			status: "tentative",
+		})
+
+		expect(event.alarms).toHaveLength(2)
+		expect(event.alarms[0]).toEqual({ trigger: "-PT15M", action: "DISPLAY" })
+		expect(event.alarms[1]).toEqual({ trigger: "-PT5M", action: "AUDIO" })
+	})
+
+	test("parses an all-day event with optional fields as null", () => {
+		const events = parseICalEvents(loadFixture("all-day-event.ics"), null)
+
+		expect(events).toHaveLength(1)
+		const event = events[0]!
+
+		expect(event.isAllDay).toBe(true)
+		expect(event.title).toBe("Company Holiday")
+		expect(event.calendarName).toBeNull()
+		expect(event.location).toBeNull()
+		expect(event.description).toBeNull()
+		expect(event.url).toBeNull()
+		expect(event.organizer).toBeNull()
+		expect(event.attendees).toEqual([])
+		expect(event.alarms).toEqual([])
+	})
+
+	test("parses recurring event with exception", () => {
+		const events = parseICalEvents(loadFixture("recurring-event.ics"), "Team")
+
+		expect(events).toHaveLength(2)
+		expect(events[0]!.uid).toBe("recurring-001@test")
+		expect(events[1]!.uid).toBe("recurring-001@test")
+
+		const base = events.find((e) => e.title === "Weekly Sync")
+		expect(base).toBeDefined()
+		expect(base!.recurrenceId).toBeNull()
+
+		const exception = events.find((e) => e.title === "Weekly Sync (moved)")
+		expect(exception).toBeDefined()
+		expect(exception!.recurrenceId).not.toBeNull()
+	})
+
+	test("parses minimal event with defaults", () => {
+		const events = parseICalEvents(loadFixture("minimal-event.ics"), null)
+
+		expect(events).toHaveLength(1)
+		const event = events[0]!
+
+		expect(event.uid).toBe("minimal-001@test")
+		expect(event.title).toBe("Quick Chat")
+		expect(event.startDate).toEqual(new Date("2026-01-15T18:00:00Z"))
+		expect(event.endDate).toEqual(new Date("2026-01-15T19:00:00Z"))
+		expect(event.location).toBeNull()
+		expect(event.description).toBeNull()
+		expect(event.status).toBeNull()
+		expect(event.url).toBeNull()
+		expect(event.organizer).toBeNull()
+		expect(event.attendees).toEqual([])
+		expect(event.alarms).toEqual([])
+		expect(event.recurrenceId).toBeNull()
+	})
+
+	test("parses cancelled status", () => {
+		const events = parseICalEvents(loadFixture("cancelled-event.ics"), null)
+		expect(events[0]!.status).toBe("cancelled")
+	})
+})

packages/aris-source-caldav/src/ical-parser.ts

@@ -0,0 +1,153 @@
+import ICAL from "ical.js"
+
+import {
+	AttendeeRole,
+	AttendeeStatus,
+	CalDavEventStatus,
+	type CalDavAlarm,
+	type CalDavAttendee,
+	type CalDavEventData,
+} from "./types.ts"
+
+/**
+ * Parses a raw iCalendar string and extracts all VEVENT components
+ * into CalDavEventData objects.
+ *
+ * @param icsData - Raw iCalendar string from a CalDAV response
+ * @param calendarName - Display name of the calendar this event belongs to
+ */
+export function parseICalEvents(icsData: string, calendarName: string | null): CalDavEventData[] {
+	const jcal = ICAL.parse(icsData)
+	const comp = new ICAL.Component(jcal)
+	const vevents = comp.getAllSubcomponents("vevent")
+
+	return vevents.map((vevent: InstanceType<typeof ICAL.Component>) =>
+		parseVEvent(vevent, calendarName),
+	)
+}
+
+function parseVEvent(
+	vevent: InstanceType<typeof ICAL.Component>,
+	calendarName: string | null,
+): CalDavEventData {
+	const event = new ICAL.Event(vevent)
+
+	return {
+		uid: event.uid ?? "",
+		title: event.summary ?? "",
+		startDate: event.startDate?.toJSDate() ?? new Date(0),
+		endDate: event.endDate?.toJSDate() ?? new Date(0),
+		isAllDay: event.startDate?.isDate ?? false,
+		location: event.location ?? null,
+		description: event.description ?? null,
+		calendarName,
+		status: parseStatus(asStringOrNull(vevent.getFirstPropertyValue("status"))),
+		url: asStringOrNull(vevent.getFirstPropertyValue("url")),
+		organizer: parseOrganizer(asStringOrNull(event.organizer), vevent),
+		attendees: parseAttendees(Array.isArray(event.attendees) ? event.attendees : []),
+		alarms: parseAlarms(vevent),
+		recurrenceId: event.recurrenceId ? event.recurrenceId.toString() : null,
+	}
+}
+
+function parseStatus(raw: string | null): CalDavEventStatus | null {
+	if (!raw) return null
+	switch (raw.toLowerCase()) {
+		case "confirmed":
+			return CalDavEventStatus.Confirmed
+		case "tentative":
+			return CalDavEventStatus.Tentative
+		case "cancelled":
+			return CalDavEventStatus.Cancelled
+		default:
+			return null
+	}
+}
+
+function parseOrganizer(
+	value: string | null,
+	vevent: InstanceType<typeof ICAL.Component>,
+): string | null {
+	if (!value) return null
+
+	// Try CN parameter first
+	const prop = vevent.getFirstProperty("organizer")
+	if (prop) {
+		const cn = prop.getParameter("cn") as string | undefined
+		if (cn) return cn
+	}
+
+	// Fall back to mailto: value
+	return value.replace(/^mailto:/i, "")
+}
+
+function parseAttendees(properties: unknown[]): CalDavAttendee[] {
+	if (properties.length === 0) return []
+
+	return properties.flatMap((prop) => {
+		if (!prop || typeof prop !== "object" || !("getFirstValue" in prop)) return []
+		const p = prop as InstanceType<typeof ICAL.Property>
+		const value = asStringOrNull(p.getFirstValue())
+		const cn = asStringOrNull(p.getParameter("cn"))
+		const role = asStringOrNull(p.getParameter("role"))
+		const partstat = asStringOrNull(p.getParameter("partstat"))
+
+		return [
+			{
+				name: cn,
+				email: value ? value.replace(/^mailto:/i, "") : null,
+				role: parseAttendeeRole(role),
+				status: parseAttendeeStatus(partstat),
+			},
+		]
+	})
+}
+
+function parseAttendeeRole(raw: string | null): AttendeeRole | null {
+	if (!raw) return null
+	switch (raw.toUpperCase()) {
+		case "CHAIR":
+			return AttendeeRole.Chair
+		case "REQ-PARTICIPANT":
+			return AttendeeRole.Required
+		case "OPT-PARTICIPANT":
+			return AttendeeRole.Optional
+		default:
+			return null
+	}
+}
+
+function parseAttendeeStatus(raw: string | null): AttendeeStatus | null {
+	if (!raw) return null
+	switch (raw.toUpperCase()) {
+		case "ACCEPTED":
+			return AttendeeStatus.Accepted
+		case "DECLINED":
+			return AttendeeStatus.Declined
+		case "TENTATIVE":
+			return AttendeeStatus.Tentative
+		case "NEEDS-ACTION":
+			return AttendeeStatus.NeedsAction
+		default:
+			return null
+	}
+}
+
+function parseAlarms(vevent: InstanceType<typeof ICAL.Component>): CalDavAlarm[] {
+	const valarms = vevent.getAllSubcomponents("valarm")
+	if (!valarms || valarms.length === 0) return []
+
+	return valarms.map((valarm: InstanceType<typeof ICAL.Component>) => {
+		const trigger = valarm.getFirstPropertyValue("trigger")
+		const action = asStringOrNull(valarm.getFirstPropertyValue("action"))
+
+		return {
+			trigger: trigger ? trigger.toString() : "",
+			action: action ?? "DISPLAY",
+		}
+	})
+}
+
+function asStringOrNull(value: unknown): string | null {
+	return typeof value === "string" ? value : null
+}

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

@@ -0,0 +1,15 @@
+export { CalDavCalendarKey, type CalendarContext } from "./calendar-context.ts"
+export { CalDavSource, type CalDavSourceOptions } from "./caldav-source.ts"
+export { parseICalEvents } from "./ical-parser.ts"
+export {
+	AttendeeRole,
+	AttendeeStatus,
+	CalDavEventStatus,
+	type CalDavAlarm,
+	type CalDavAttendee,
+	type CalDavDAVCalendar,
+	type CalDavDAVClient,
+	type CalDavDAVObject,
+	type CalDavEventData,
+	type CalDavFeedItem,
+} from "./types.ts"

packages/aris-source-caldav/src/types.ts

@@ -0,0 +1,93 @@
+import type { FeedItem } from "@aris/core"
+
+// -- Event status --
+
+export const CalDavEventStatus = {
+	Confirmed: "confirmed",
+	Tentative: "tentative",
+	Cancelled: "cancelled",
+} as const
+
+export type CalDavEventStatus = (typeof CalDavEventStatus)[keyof typeof CalDavEventStatus]
+
+// -- Attendee types --
+
+export const AttendeeRole = {
+	Chair: "chair",
+	Required: "required",
+	Optional: "optional",
+} as const
+
+export type AttendeeRole = (typeof AttendeeRole)[keyof typeof AttendeeRole]
+
+export const AttendeeStatus = {
+	Accepted: "accepted",
+	Declined: "declined",
+	Tentative: "tentative",
+	NeedsAction: "needs-action",
+} as const
+
+export type AttendeeStatus = (typeof AttendeeStatus)[keyof typeof AttendeeStatus]
+
+export interface CalDavAttendee {
+	name: string | null
+	email: string | null
+	role: AttendeeRole | null
+	status: AttendeeStatus | null
+}
+
+// -- Alarm --
+
+export interface CalDavAlarm {
+	/** ISO 8601 duration relative to event start, e.g. "-PT15M" */
+	trigger: string
+	/** e.g. "DISPLAY", "AUDIO" */
+	action: string
+}
+
+// -- Event data --
+
+export interface CalDavEventData extends Record<string, unknown> {
+	uid: string
+	title: string
+	startDate: Date
+	endDate: Date
+	isAllDay: boolean
+	location: string | null
+	description: string | null
+	calendarName: string | null
+	status: CalDavEventStatus | null
+	url: string | null
+	organizer: string | null
+	attendees: CalDavAttendee[]
+	alarms: CalDavAlarm[]
+	recurrenceId: string | null
+}
+
+// -- Feed item --
+
+export type CalDavFeedItem = FeedItem<"caldav-event", CalDavEventData>
+
+// -- DAV client interface --
+
+export interface CalDavDAVObject {
+	data?: unknown
+	etag?: string
+	url: string
+}
+
+export interface CalDavDAVCalendar {
+	displayName?: string | Record<string, unknown>
+	url: string
+}
+
+/** Subset of tsdav's DAVClient used by CalDavSource. */
+export interface CalDavDAVClient {
+	login(): Promise<void>
+	fetchCalendars(): Promise<CalDavDAVCalendar[]>
+	fetchCalendarObjects(params: {
+		calendar: CalDavDAVCalendar
+		timeRange: { start: string; end: string }
+	}): Promise<CalDavDAVObject[]>
+	credentials: Record<string, unknown>
+}