diff --git a/.env.example b/.env.example
index e46684c..f77bfec 100644
--- a/.env.example
+++ b/.env.example
@@ -34,3 +34,11 @@ NPM_AUTH_TOKEN=
 
 # === MinIO (über mana-media) ===
 CARDS_MEDIA_BUCKET=cards-storage
+
+# === DSGVO Service-Key ===
+# X-Service-Key-Wert, mit dem mana-admin DSGVO-Export/Delete-Calls
+# autorisiert. In Prod aus mana-auth.app_service_keys.
+CARDS_DSGVO_SERVICE_KEY=msk_dev_change_me_dsgvo
+
+# === Public-URL für Deep-Links in Share-Handlers + Search-Hits ===
+CARDS_PUBLIC_URL=http://localhost:3082
diff --git a/apps/api/src/index.ts b/apps/api/src/index.ts
index 7f5d9d4..e83a88a 100644
--- a/apps/api/src/index.ts
+++ b/apps/api/src/index.ts
@@ -6,6 +6,10 @@ import { healthRoute } from './routes/health.ts';
 import { decksRouter } from './routes/decks.ts';
 import { cardsRouter } from './routes/cards.ts';
 import { reviewsRouter } from './routes/reviews.ts';
+import { shareRouter } from './routes/share.ts';
+import { toolsRouter } from './routes/tools.ts';
+import { searchRouter } from './routes/search.ts';
+import { dsgvoRouter } from './routes/dsgvo.ts';
 
 const app = new Hono();
 
@@ -31,6 +35,10 @@ app.route('/.well-known/mana-app.json', manifestRoute);
 app.route('/api/v1/decks', decksRouter());
 app.route('/api/v1/cards', cardsRouter());
 app.route('/api/v1/reviews', reviewsRouter());
+app.route('/api/v1/share', shareRouter());
+app.route('/api/v1/tools', toolsRouter());
+app.route('/api/v1/search', searchRouter());
+app.route('/api/v1/dsgvo', dsgvoRouter());
 
 app.get('/', (c) =>
 	c.json({
diff --git a/apps/api/src/lib/inbox-deck.ts b/apps/api/src/lib/inbox-deck.ts
new file mode 100644
index 0000000..5d9a09d
--- /dev/null
+++ b/apps/api/src/lib/inbox-deck.ts
@@ -0,0 +1,40 @@
+import { and, eq } from 'drizzle-orm';
+
+import type { CardsDb } from '../db/connection.ts';
+import { decks } from '../db/schema/index.ts';
+import { ulid } from './ulid.ts';
+
+/** Stabiler Name des Inbox-Decks pro User. Auto-Created bei erstem Share. */
+export const INBOX_DECK_NAME = 'Inbox';
+
+/**
+ * Holt das Inbox-Deck eines Users oder legt es neu an.
+ * Wird von allen Share-Receive-Handlern benutzt — eingehende
+ * Shares landen immer in der Inbox, der User kann sie später
+ * in andere Decks umsortieren.
+ */
+export async function ensureInboxDeck(db: CardsDb, userId: string) {
+	const [existing] = await db
+		.select()
+		.from(decks)
+		.where(and(eq(decks.userId, userId), eq(decks.name, INBOX_DECK_NAME)))
+		.limit(1);
+	if (existing) return existing;
+
+	const now = new Date();
+	const [created] = await db
+		.insert(decks)
+		.values({
+			id: ulid(),
+			userId,
+			name: INBOX_DECK_NAME,
+			description: 'Eingehende Shares aus anderen Apps. Sortiere sie in eigene Decks um.',
+			color: '#888888',
+			visibility: 'private',
+			fsrsSettings: {},
+			createdAt: now,
+			updatedAt: now,
+		})
+		.returning();
+	return created;
+}
diff --git a/apps/api/src/lib/search.ts b/apps/api/src/lib/search.ts
new file mode 100644
index 0000000..c90d47e
--- /dev/null
+++ b/apps/api/src/lib/search.ts
@@ -0,0 +1,76 @@
+import { and, eq, sql } from 'drizzle-orm';
+
+import type { CardsDb } from '../db/connection.ts';
+import { cards, decks } from '../db/schema/index.ts';
+
+const APP_BASE_URL = process.env.CARDS_PUBLIC_URL ?? 'https://cardecky.mana.how';
+
+export type SearchHit = {
+	id: string;
+	type: 'card';
+	title: string;
+	snippet?: string;
+	link: string;
+	score: number;
+	created_at?: string;
+	updated_at?: string;
+};
+
+/**
+ * MVP-Suche: case-insensitive ILIKE auf der `fields` JSONB-Spalte
+ * und auf Deck-Name. Vector-/Trigram-Suche kommt später (eigener
+ * Index, separate Phase).
+ *
+ * Score-Heuristik MVP: 1.0 für Treffer (kein Ranking), absteigend
+ * sortiert nach updated_at. Echtes Scoring wenn pg_trgm/vector
+ * eingerichtet sind.
+ */
+export async function searchUserCards(
+	db: CardsDb,
+	userId: string,
+	query: string,
+	maxResults = 30
+): Promise<{ hits: SearchHit[]; tookMs: number }> {
+	const t0 = Date.now();
+	const pattern = `%${query.replace(/[%_]/g, '\\$&')}%`;
+
+	const rows = await db
+		.select({
+			id: cards.id,
+			deckId: cards.deckId,
+			fields: cards.fields,
+			createdAt: cards.createdAt,
+			updatedAt: cards.updatedAt,
+			deckName: decks.name,
+		})
+		.from(cards)
+		.innerJoin(decks, eq(decks.id, cards.deckId))
+		.where(
+			and(
+				eq(cards.userId, userId),
+				sql`(${cards.fields}::text ILIKE ${pattern} OR ${decks.name} ILIKE ${pattern})`
+			)
+		)
+		.orderBy(sql`${cards.updatedAt} DESC`)
+		.limit(Math.min(maxResults, 200));
+
+	const hits = rows.map((r): SearchHit => {
+		const fields = r.fields as Record<string, string>;
+		const front = fields.front ?? '';
+		const back = fields.back ?? '';
+		const title = front.split('\n')[0]?.slice(0, 200) ?? r.deckName;
+		const snippet = back.slice(0, 200) || undefined;
+		return {
+			id: r.id,
+			type: 'card',
+			title: title || '(leer)',
+			snippet,
+			link: `${APP_BASE_URL}/c/${r.id}`,
+			score: 1.0,
+			created_at: r.createdAt.toISOString(),
+			updated_at: r.updatedAt.toISOString(),
+		};
+	});
+
+	return { hits, tookMs: Date.now() - t0 };
+}
diff --git a/apps/api/src/middleware/service-key.ts b/apps/api/src/middleware/service-key.ts
new file mode 100644
index 0000000..bfc34a5
--- /dev/null
+++ b/apps/api/src/middleware/service-key.ts
@@ -0,0 +1,41 @@
+import type { MiddlewareHandler } from 'hono';
+
+/**
+ * Service-Key-Middleware für DSGVO-Endpunkte und sonstige
+ * service-zu-service-Calls.
+ *
+ * Heute (Phase 5): vergleicht `X-Service-Key`-Header per
+ * constant-time-Compare gegen `process.env.CARDS_DSGVO_SERVICE_KEY`.
+ *
+ * Phase F-1: ersetzt durch Verifikation gegen mana-auth's
+ * `apps.app_service_keys` Tabelle (caller-App = `mana-admin`).
+ */
+
+function constantTimeEquals(a: string, b: string): boolean {
+	if (a.length !== b.length) return false;
+	let mismatch = 0;
+	for (let i = 0; i < a.length; i++) {
+		mismatch |= a.charCodeAt(i) ^ b.charCodeAt(i);
+	}
+	return mismatch === 0;
+}
+
+export function serviceKeyAuth(opts: { envVar: string }): MiddlewareHandler {
+	return async (c, next) => {
+		const expected = process.env[opts.envVar];
+		if (!expected) {
+			return c.json(
+				{
+					error: 'service_key_not_configured',
+					detail: `${opts.envVar} env-var is not set`,
+				},
+				500
+			);
+		}
+		const provided = c.req.header('X-Service-Key');
+		if (!provided || !constantTimeEquals(provided, expected)) {
+			return c.json({ error: 'service_key_invalid' }, 401);
+		}
+		await next();
+	};
+}
diff --git a/apps/api/src/routes/dsgvo.ts b/apps/api/src/routes/dsgvo.ts
new file mode 100644
index 0000000..69ca893
--- /dev/null
+++ b/apps/api/src/routes/dsgvo.ts
@@ -0,0 +1,121 @@
+import { eq } from 'drizzle-orm';
+import { Hono } from 'hono';
+
+import { getDb, type CardsDb } from '../db/connection.ts';
+import {
+	cards,
+	decks,
+	importJobs,
+	mediaRefs,
+	reviews,
+	studySessions,
+	tags,
+} from '../db/schema/index.ts';
+import { serviceKeyAuth } from '../middleware/service-key.ts';
+
+export type DsgvoDeps = { db?: CardsDb };
+
+/**
+ * DSGVO-Endpunkte. Aufgerufen von mana-admin im Verein-DSGVO-
+ * Fan-Out (Auskunft Art. 15/20 + Löschung Art. 17).
+ *
+ * Auth: Service-Key (`X-Service-Key` muss `CARDS_DSGVO_SERVICE_KEY`
+ * matchen). Phase F-1: ersetzt durch mana-auth-Service-Key-Lookup.
+ */
+export function dsgvoRouter(deps: DsgvoDeps = {}): Hono {
+	const r = new Hono();
+	const dbOf = () => deps.db ?? getDb();
+
+	r.use('*', serviceKeyAuth({ envVar: 'CARDS_DSGVO_SERVICE_KEY' }));
+
+	/**
+	 * Voll-Export aller Cards-Daten eines Users. Liefert serialisier-
+	 * bares JSON. mana-admin packt das mit den Antworten anderer Apps
+	 * in einen ZIP für den User.
+	 */
+	r.get('/export', async (c) => {
+		const userId = c.req.query('user_id');
+		if (!userId) return c.json({ error: 'missing_user_id' }, 400);
+
+		const db = dbOf();
+		const [decksRows, cardsRows, reviewsRows, sessionsRows, tagsRows, mediaRows, importsRows] =
+			await Promise.all([
+				db.select().from(decks).where(eq(decks.userId, userId)),
+				db.select().from(cards).where(eq(cards.userId, userId)),
+				db.select().from(reviews).where(eq(reviews.userId, userId)),
+				db.select().from(studySessions).where(eq(studySessions.userId, userId)),
+				db.select().from(tags).where(eq(tags.userId, userId)),
+				db.select().from(mediaRefs).where(eq(mediaRefs.userId, userId)),
+				db.select().from(importJobs).where(eq(importJobs.userId, userId)),
+			]);
+
+		return c.json({
+			user_id: userId,
+			exported_at: new Date().toISOString(),
+			app: 'cards',
+			app_version: process.env.CARDS_API_VERSION ?? '0.0.0',
+			data: {
+				decks: decksRows.map((d) => ({ ...d, createdAt: d.createdAt.toISOString(), updatedAt: d.updatedAt.toISOString() })),
+				cards: cardsRows.map((x) => ({
+					...x,
+					createdAt: x.createdAt.toISOString(),
+					updatedAt: x.updatedAt.toISOString(),
+				})),
+				reviews: reviewsRows.map((r) => ({
+					...r,
+					due: r.due.toISOString(),
+					lastReview: r.lastReview ? r.lastReview.toISOString() : null,
+				})),
+				study_sessions: sessionsRows.map((s) => ({
+					...s,
+					startedAt: s.startedAt.toISOString(),
+					finishedAt: s.finishedAt ? s.finishedAt.toISOString() : null,
+				})),
+				tags: tagsRows.map((t) => ({ ...t, createdAt: t.createdAt.toISOString() })),
+				media_refs: mediaRows.map((m) => ({ ...m, createdAt: m.createdAt.toISOString() })),
+				import_jobs: importsRows.map((j) => ({
+					...j,
+					createdAt: j.createdAt.toISOString(),
+					finishedAt: j.finishedAt ? j.finishedAt.toISOString() : null,
+				})),
+			},
+		});
+	});
+
+	/**
+	 * Vollständige Löschung aller Cards-Daten eines Users. FK-Cascades
+	 * räumen automatisch:
+	 *   decks → cards → reviews
+	 *           cards → media_refs
+	 *           cards → card_tags
+	 *           decks → tags
+	 *           decks → study_sessions
+	 * Verbleibend: import_jobs (eigene Tabelle ohne FK) — wird separat gelöscht.
+	 */
+	r.post('/delete', async (c) => {
+		const body = await c.req.json().catch(() => null);
+		const userId = (body as { user_id?: string } | null)?.user_id;
+		if (!userId) return c.json({ error: 'missing_user_id' }, 400);
+
+		const db = dbOf();
+		const [deletedDecks, deletedImports] = await db.transaction(async (tx) => {
+			const dd = await tx.delete(decks).where(eq(decks.userId, userId)).returning({ id: decks.id });
+			const di = await tx
+				.delete(importJobs)
+				.where(eq(importJobs.userId, userId))
+				.returning({ id: importJobs.id });
+			return [dd, di];
+		});
+
+		return c.json({
+			deleted: true,
+			user_id: userId,
+			counts: {
+				decks: deletedDecks.length,
+				import_jobs: deletedImports.length,
+			},
+		});
+	});
+
+	return r;
+}
diff --git a/apps/api/src/routes/search.ts b/apps/api/src/routes/search.ts
new file mode 100644
index 0000000..b201da5
--- /dev/null
+++ b/apps/api/src/routes/search.ts
@@ -0,0 +1,67 @@
+import { Hono } from 'hono';
+
+import {
+	SEARCH_ENVELOPE_VERSION,
+	type SearchResultEnvelope,
+} from '@cards/domain';
+
+import { getDb, type CardsDb } from '../db/connection.ts';
+import { authMiddleware, type AuthVars } from '../middleware/auth.ts';
+import { searchUserCards } from '../lib/search.ts';
+
+const APP_VERSION = process.env.CARDS_API_VERSION ?? '0.0.0';
+
+export type SearchDeps = { db?: CardsDb };
+
+/**
+ * GET /api/v1/search?q=...
+ *
+ * Liefert eine `SearchResultEnvelope` (Phase 5.5 — MVP) im Format,
+ * das der mana-search Aggregator erwartet. Aufrufer ist mana-search,
+ * der parallel an alle App-Endpoints fan-outet.
+ */
+export function searchRouter(deps: SearchDeps = {}): Hono<{ Variables: AuthVars }> {
+	const r = new Hono<{ Variables: AuthVars }>();
+	const dbOf = () => deps.db ?? getDb();
+
+	r.use('*', authMiddleware);
+
+	r.get('/', async (c) => {
+		const userId = c.get('userId');
+		const q = c.req.query('q')?.trim();
+		const limit = Number(c.req.query('limit') ?? 30);
+
+		if (!q) {
+			return c.json({ error: 'missing_query' }, 422);
+		}
+		if (q.length > 500) {
+			return c.json({ error: 'query_too_long', max: 500 }, 422);
+		}
+
+		const { hits, tookMs } = await searchUserCards(dbOf(), userId, q, limit);
+
+		const envelope: SearchResultEnvelope = {
+			envelope_version: SEARCH_ENVELOPE_VERSION,
+			query: q,
+			app: 'cards',
+			app_version: APP_VERSION,
+			results: hits.map((h) => ({
+				id: h.id,
+				type: 'card',
+				title: h.title,
+				snippet: h.snippet,
+				link: h.link,
+				score: h.score,
+				created_at: h.created_at,
+				updated_at: h.updated_at,
+			})),
+			total: hits.length,
+			partial: false,
+			took_ms: tookMs,
+		};
+
+		return c.json(envelope);
+	});
+
+	return r;
+}
diff --git a/apps/api/src/routes/share.ts b/apps/api/src/routes/share.ts
new file mode 100644
index 0000000..192c24d
--- /dev/null
+++ b/apps/api/src/routes/share.ts
@@ -0,0 +1,119 @@
+import { Hono } from 'hono';
+
+import { parseEnvelope, validatePayloadForType } from '@cards/domain';
+
+import manifest from '../../../../app-manifest.json' with { type: 'json' };
+
+import { getDb, type CardsDb } from '../db/connection.ts';
+import { authMiddleware, type AuthVars } from '../middleware/auth.ts';
+import { SHARE_HANDLERS, type ShareHandlerName } from '../share-handlers/index.ts';
+
+export type ShareDeps = { db?: CardsDb };
+
+/** Manifest-Lookup: Type → Handler-Name. */
+const ACCEPTS_BY_TYPE = new Map(manifest.accepts.map((a) => [a.type, a.handler] as const));
+
+export function shareRouter(deps: ShareDeps = {}): Hono<{ Variables: AuthVars }> {
+	const r = new Hono<{ Variables: AuthVars }>();
+	const dbOf = () => deps.db ?? getDb();
+
+	r.use('*', authMiddleware);
+
+	r.post('/receive', async (c) => {
+		const userId = c.get('userId');
+
+		// Body kann `{ envelope, delivery_token }` oder direkt der Envelope sein.
+		const body = await c.req.json().catch(() => null);
+		if (!body || typeof body !== 'object') {
+			return c.json({ accepted: false, reason: 'invalid_json' }, 400);
+		}
+		const wrapped = body as { envelope?: unknown; delivery_token?: string };
+		const rawEnvelope = wrapped.envelope ?? body;
+		// const deliveryToken = wrapped.delivery_token; // Phase F-1: validieren
+
+		// 1. Schema-Validierung (inkl. Cross-User-Sperre)
+		const parsed = parseEnvelope(rawEnvelope);
+		if (!parsed.success) {
+			return c.json(
+				{
+					accepted: false,
+					reason: 'envelope_invalid',
+					issues: parsed.error.issues.map(
+						(i) => `${i.path.join('.') || '<root>'}: ${i.message}`
+					),
+				},
+				422
+			);
+		}
+		const env = parsed.data;
+
+		// 2. User-Match
+		if (env.to.user_id !== userId) {
+			return c.json({ accepted: false, reason: 'user_id_mismatch' }, 403);
+		}
+
+		// 3. Empfänger-App-Match
+		if (env.to.app !== manifest.id) {
+			return c.json(
+				{
+					accepted: false,
+					reason: 'wrong_recipient',
+					expected: manifest.id,
+					actual: env.to.app,
+				},
+				422
+			);
+		}
+
+		// 4. Type akzeptiert?
+		const handlerName = ACCEPTS_BY_TYPE.get(env.type);
+		if (!handlerName) {
+			return c.json(
+				{ accepted: false, reason: 'type_not_accepted', type: env.type },
+				422
+			);
+		}
+
+		// 5. Payload validieren gegen sein eigenes Schema
+		const payloadCheck = validatePayloadForType(env.type, env.payload);
+		if (!payloadCheck.success) {
+			return c.json(
+				{
+					accepted: false,
+					reason: payloadCheck.error,
+					issues: 'issues' in payloadCheck ? payloadCheck.issues : undefined,
+				},
+				422
+			);
+		}
+
+		// 6. Handler holen + dispatchen
+		const handler = SHARE_HANDLERS[handlerName as ShareHandlerName];
+		if (!handler) {
+			return c.json(
+				{ accepted: false, reason: 'handler_not_registered', handler: handlerName },
+				501
+			);
+		}
+
+		try {
+			const result = await handler(dbOf(), userId, payloadCheck.data as never);
+			return c.json({
+				accepted: true,
+				target_link: result.target_link,
+				resulting_id: result.resulting_id,
+			});
+		} catch (e) {
+			return c.json(
+				{
+					accepted: false,
+					reason: 'handler_error',
+					message: (e as Error).message,
+				},
+				500
+			);
+		}
+	});
+
+	return r;
+}
diff --git a/apps/api/src/routes/tools.ts b/apps/api/src/routes/tools.ts
new file mode 100644
index 0000000..7018c8d
--- /dev/null
+++ b/apps/api/src/routes/tools.ts
@@ -0,0 +1,145 @@
+import { eq } from 'drizzle-orm';
+import { Hono } from 'hono';
+
+import {
+	CardsCreateInputSchema,
+	CardsSearchInputSchema,
+	newReview,
+	subIndexCount,
+} from '@cards/domain';
+
+import { getDb, type CardsDb } from '../db/connection.ts';
+import { cards, decks, reviews } from '../db/schema/index.ts';
+import { authMiddleware, type AuthVars } from '../middleware/auth.ts';
+import { ulid } from '../lib/ulid.ts';
+import { searchUserCards } from '../lib/search.ts';
+
+const APP_BASE_URL = process.env.CARDS_PUBLIC_URL ?? 'https://cardecky.mana.how';
+const APP_VERSION = process.env.CARDS_API_VERSION ?? '0.0.0';
+
+export type ToolsDeps = { db?: CardsDb };
+
+/**
+ * Tool-Invoke-Endpoint für mana-mcp / Persona-Runner / Claude.
+ * Dispatch nach `:name`. Auth: User-JWT (X-User-Id-Header im Dev-Stub).
+ *
+ * Phase F-1: zusätzlich Service-Key-Pfad für mcp-getriggerte Calls
+ * mit user-on-behalf-of-Token.
+ */
+export function toolsRouter(deps: ToolsDeps = {}): Hono<{ Variables: AuthVars }> {
+	const r = new Hono<{ Variables: AuthVars }>();
+	const dbOf = () => deps.db ?? getDb();
+
+	r.use('*', authMiddleware);
+
+	r.post('/:name', async (c) => {
+		const userId = c.get('userId');
+		const name = c.req.param('name');
+		const body = await c.req.json().catch(() => null);
+		if (body == null) return c.json({ error: 'invalid_json' }, 400);
+
+		switch (name) {
+			case 'cards.create': {
+				const parsed = CardsCreateInputSchema.safeParse(body);
+				if (!parsed.success) {
+					return c.json(
+						{ error: 'invalid_input', issues: parsed.error.issues.map((i) => i.message) },
+						422
+					);
+				}
+				const [deck] = await dbOf()
+					.select({ id: decks.id, userId: decks.userId })
+					.from(decks)
+					.where(eq(decks.id, parsed.data.deck_id))
+					.limit(1);
+				if (!deck) return c.json({ error: 'deck_not_found' }, 404);
+				if (deck.userId !== userId) return c.json({ error: 'deck_not_owned' }, 403);
+
+				const cardId = ulid();
+				const now = new Date();
+				const [row] = await dbOf().transaction(async (tx) => {
+					const [card] = await tx
+						.insert(cards)
+						.values({
+							id: cardId,
+							deckId: parsed.data.deck_id,
+							userId,
+							type: parsed.data.type,
+							fields: parsed.data.fields,
+							mediaRefs: parsed.data.media_refs ?? [],
+							createdAt: now,
+							updatedAt: now,
+						})
+						.returning();
+					const initial = Array.from(
+						{ length: subIndexCount(parsed.data.type) },
+						(_, i) => i
+					).map((subIndex) => {
+						const r = newReview({ userId, cardId, subIndex, now });
+						return {
+							cardId: r.card_id,
+							subIndex: r.sub_index,
+							userId: r.user_id,
+							due: new Date(r.due),
+							stability: r.stability,
+							difficulty: r.difficulty,
+							elapsedDays: r.elapsed_days,
+							scheduledDays: r.scheduled_days,
+							learningSteps: r.learning_steps,
+							reps: r.reps,
+							lapses: r.lapses,
+							state: r.state,
+							lastReview: r.last_review ? new Date(r.last_review) : null,
+						};
+					});
+					if (initial.length > 0) await tx.insert(reviews).values(initial);
+					return [card];
+				});
+				return c.json({
+					id: row.id,
+					deck_id: row.deckId,
+					user_id: row.userId,
+					type: row.type,
+					fields: row.fields,
+					media_refs: row.mediaRefs ?? [],
+					content_hash: row.contentHash,
+					created_at: row.createdAt.toISOString(),
+					updated_at: row.updatedAt.toISOString(),
+				});
+			}
+
+			case 'cards.search': {
+				const parsed = CardsSearchInputSchema.safeParse(body);
+				if (!parsed.success) {
+					return c.json(
+						{ error: 'invalid_input', issues: parsed.error.issues.map((i) => i.message) },
+						422
+					);
+				}
+				const max = parsed.data.max_results ?? 30;
+				const { hits, tookMs } = await searchUserCards(dbOf(), userId, parsed.data.query, max);
+				return c.json({
+					query: parsed.data.query,
+					results: hits.map((h) => ({
+						id: h.id,
+						type: 'card' as const,
+						title: h.title,
+						snippet: h.snippet,
+						link: h.link,
+						score: h.score,
+					})),
+					total: hits.length,
+					took_ms: tookMs,
+					app: 'cards',
+					app_version: APP_VERSION,
+					base_url: APP_BASE_URL,
+				});
+			}
+
+			default:
+				return c.json({ error: 'unknown_tool', name }, 404);
+		}
+	});
+
+	return r;
+}
diff --git a/apps/api/src/share-handlers/index.ts b/apps/api/src/share-handlers/index.ts
new file mode 100644
index 0000000..6fa7443
--- /dev/null
+++ b/apps/api/src/share-handlers/index.ts
@@ -0,0 +1,130 @@
+import { newReview, subIndexCount } from '@cards/domain';
+import type { QuotePayload, TextPayload, UrlPayload } from '@cards/domain';
+
+import type { CardsDb } from '../db/connection.ts';
+import { cards, reviews } from '../db/schema/index.ts';
+import { ensureInboxDeck } from '../lib/inbox-deck.ts';
+import { ulid } from '../lib/ulid.ts';
+
+/**
+ * Antwort-Shape eines Share-Handlers — wird vom Receive-Endpoint
+ * an den sendenden Peer zurückgegeben.
+ */
+export type HandlerResult = {
+	target_link: string;
+	resulting_id: string;
+};
+
+const APP_BASE_URL = process.env.CARDS_PUBLIC_URL ?? 'https://cardecky.mana.how';
+
+/**
+ * Legt eine basic-Karte mit (front,back) im Inbox-Deck an, inkl.
+ * der ts-fsrs-Initial-Reviews. Gibt Karte-ID + Deep-Link zurück.
+ */
+async function persistCardInInbox(
+	db: CardsDb,
+	userId: string,
+	front: string,
+	back: string
+): Promise<HandlerResult> {
+	const inbox = await ensureInboxDeck(db, userId);
+	const cardId = ulid();
+	const now = new Date();
+
+	await db.transaction(async (tx) => {
+		await tx.insert(cards).values({
+			id: cardId,
+			deckId: inbox.id,
+			userId,
+			type: 'basic',
+			fields: { front, back },
+			mediaRefs: [],
+			createdAt: now,
+			updatedAt: now,
+		});
+
+		const initial = Array.from({ length: subIndexCount('basic') }, (_, i) => i).map(
+			(subIndex) => {
+				const r = newReview({ userId, cardId, subIndex, now });
+				return {
+					cardId: r.card_id,
+					subIndex: r.sub_index,
+					userId: r.user_id,
+					due: new Date(r.due),
+					stability: r.stability,
+					difficulty: r.difficulty,
+					elapsedDays: r.elapsed_days,
+					scheduledDays: r.scheduled_days,
+					learningSteps: r.learning_steps,
+					reps: r.reps,
+					lapses: r.lapses,
+					state: r.state,
+					lastReview: r.last_review ? new Date(r.last_review) : null,
+				};
+			}
+		);
+		if (initial.length > 0) {
+			await tx.insert(reviews).values(initial);
+		}
+	});
+
+	return {
+		target_link: `${APP_BASE_URL}/c/${cardId}`,
+		resulting_id: cardId,
+	};
+}
+
+/**
+ * mana/quote → Karte. Front = Zitat-Text, Back = Quelle (URL bevorzugt,
+ * sonst Source-String, sonst leer).
+ */
+export async function createCardFromQuote(
+	db: CardsDb,
+	userId: string,
+	payload: QuotePayload
+): Promise<HandlerResult> {
+	const front = payload.text;
+	const back = payload.source_url ?? payload.source ?? '';
+	return persistCardInInbox(db, userId, front, back);
+}
+
+/**
+ * mana/url → Karte. Front = Titel (oder URL falls kein Titel),
+ * Back = URL + Description/Snippet.
+ */
+export async function saveLinkAsCard(
+	db: CardsDb,
+	userId: string,
+	payload: UrlPayload
+): Promise<HandlerResult> {
+	const front = payload.title ?? payload.url;
+	const summary = payload.description ?? payload.snippet ?? '';
+	const back = summary ? `${payload.url}\n\n${summary}` : payload.url;
+	return persistCardInInbox(db, userId, front, back);
+}
+
+/**
+ * mana/text → Karte. Front = erste Zeile (oder erste 200 Zeichen),
+ * Back = Rest. Heuristisch — User kann später trennen.
+ */
+export async function createCardFromText(
+	db: CardsDb,
+	userId: string,
+	payload: TextPayload
+): Promise<HandlerResult> {
+	const text = payload.text.trim();
+	const firstNl = text.indexOf('\n');
+	const frontEnd = firstNl > 0 && firstNl < 200 ? firstNl : Math.min(200, text.length);
+	const front = text.slice(0, frontEnd).trim();
+	const back = text.slice(frontEnd).trim();
+	return persistCardInInbox(db, userId, front, back || '(weiter ausarbeiten)');
+}
+
+/** Manifest-Handler-Map. Key = `accepts[].handler` aus app-manifest.json. */
+export const SHARE_HANDLERS = {
+	create_card_from_quote: createCardFromQuote,
+	save_link_as_card: saveLinkAsCard,
+	create_card_from_text: createCardFromText,
+} as const;
+
+export type ShareHandlerName = keyof typeof SHARE_HANDLERS;
diff --git a/apps/api/tests/dsgvo.test.ts b/apps/api/tests/dsgvo.test.ts
new file mode 100644
index 0000000..b127d7a
--- /dev/null
+++ b/apps/api/tests/dsgvo.test.ts
@@ -0,0 +1,110 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { Hono } from 'hono';
+
+import { dsgvoRouter } from '../src/routes/dsgvo.ts';
+import type { CardsDb } from '../src/db/connection.ts';
+
+const ORIG_ENV = process.env.CARDS_DSGVO_SERVICE_KEY;
+const TEST_KEY = 'msk_test_dsgvo_key_42';
+
+beforeEach(() => {
+	process.env.CARDS_DSGVO_SERVICE_KEY = TEST_KEY;
+});
+
+afterEach(() => {
+	if (ORIG_ENV === undefined) {
+		delete process.env.CARDS_DSGVO_SERVICE_KEY;
+	} else {
+		process.env.CARDS_DSGVO_SERVICE_KEY = ORIG_ENV;
+	}
+});
+
+function buildApp() {
+	const stub = {
+		select: () => ({ from: () => ({ where: () => [] as never[] }) }),
+		delete: () => ({ where: () => ({ returning: async () => [] }) }),
+		transaction: async (fn: (tx: unknown) => unknown) =>
+			fn({
+				delete: () => ({ where: () => ({ returning: async () => [] }) }),
+			}),
+	};
+	const app = new Hono();
+	app.route('/api/v1/dsgvo', dsgvoRouter({ db: stub as unknown as CardsDb }));
+	return { app };
+}
+
+describe('dsgvoRouter — Service-Key-Gate', () => {
+	it('GET /export ohne Service-Key ist 401', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/dsgvo/export?user_id=u-1');
+		expect(res.status).toBe(401);
+	});
+
+	it('POST /delete mit falschem Key ist 401', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/dsgvo/delete', {
+			method: 'POST',
+			headers: { 'X-Service-Key': 'wrong', 'Content-Type': 'application/json' },
+			body: JSON.stringify({ user_id: 'u-1' }),
+		});
+		expect(res.status).toBe(401);
+	});
+
+	it('GET /export mit Key + ohne user_id ist 400', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/dsgvo/export', {
+			headers: { 'X-Service-Key': TEST_KEY },
+		});
+		expect(res.status).toBe(400);
+	});
+
+	it('GET /export mit Key + user_id liefert JSON-Bundle', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/dsgvo/export?user_id=u-1', {
+			headers: { 'X-Service-Key': TEST_KEY },
+		});
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as {
+			user_id: string;
+			app: string;
+			data: { decks: unknown[]; cards: unknown[]; reviews: unknown[] };
+		};
+		expect(body.user_id).toBe('u-1');
+		expect(body.app).toBe('cards');
+		expect(Array.isArray(body.data.decks)).toBe(true);
+		expect(Array.isArray(body.data.cards)).toBe(true);
+		expect(Array.isArray(body.data.reviews)).toBe(true);
+	});
+
+	it('POST /delete mit Key + user_id liefert counts', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/dsgvo/delete', {
+			method: 'POST',
+			headers: { 'X-Service-Key': TEST_KEY, 'Content-Type': 'application/json' },
+			body: JSON.stringify({ user_id: 'u-1' }),
+		});
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as {
+			deleted: boolean;
+			user_id: string;
+			counts: { decks: number; import_jobs: number };
+		};
+		expect(body.deleted).toBe(true);
+		expect(body.user_id).toBe('u-1');
+		expect(body.counts.decks).toBe(0);
+		expect(body.counts.import_jobs).toBe(0);
+	});
+});
+
+describe('dsgvoRouter — Key-not-configured Pfad', () => {
+	it('Wenn ENV fehlt → 500 service_key_not_configured', async () => {
+		delete process.env.CARDS_DSGVO_SERVICE_KEY;
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/dsgvo/export?user_id=u-1', {
+			headers: { 'X-Service-Key': 'whatever' },
+		});
+		expect(res.status).toBe(500);
+		const body = (await res.json()) as { error: string };
+		expect(body.error).toBe('service_key_not_configured');
+	});
+});
diff --git a/apps/api/tests/search.test.ts b/apps/api/tests/search.test.ts
new file mode 100644
index 0000000..5120308
--- /dev/null
+++ b/apps/api/tests/search.test.ts
@@ -0,0 +1,67 @@
+import { describe, it, expect } from 'vitest';
+import { Hono } from 'hono';
+
+import { searchRouter } from '../src/routes/search.ts';
+import type { CardsDb } from '../src/db/connection.ts';
+
+function buildApp() {
+	const stub = {
+		select: () => ({
+			from: () => ({
+				innerJoin: () => ({
+					where: () => ({ orderBy: () => ({ limit: () => [] }) }),
+				}),
+			}),
+		}),
+	};
+	const app = new Hono();
+	app.route('/api/v1/search', searchRouter({ db: stub as unknown as CardsDb }));
+	return { app };
+}
+
+describe('searchRouter — Auth-Gate', () => {
+	it('GET ohne X-User-Id ist 401', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/search?q=foo');
+		expect(res.status).toBe(401);
+	});
+});
+
+describe('searchRouter — Query-Validation', () => {
+	it('GET ohne q ist 422', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/search', {
+			headers: { 'X-User-Id': 'u-1' },
+		});
+		expect(res.status).toBe(422);
+	});
+
+	it('GET mit q über 500 Zeichen ist 422', async () => {
+		const { app } = buildApp();
+		const long = 'x'.repeat(501);
+		const res = await app.request(`/api/v1/search?q=${encodeURIComponent(long)}`, {
+			headers: { 'X-User-Id': 'u-1' },
+		});
+		expect(res.status).toBe(422);
+	});
+
+	it('GET mit gültigem q liefert SearchResultEnvelope', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/search?q=Konfuzius', {
+			headers: { 'X-User-Id': 'u-1' },
+		});
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as {
+			envelope_version: string;
+			query: string;
+			app: string;
+			results: unknown[];
+			partial: boolean;
+		};
+		expect(body.envelope_version).toBe('0.1');
+		expect(body.query).toBe('Konfuzius');
+		expect(body.app).toBe('cards');
+		expect(Array.isArray(body.results)).toBe(true);
+		expect(body.partial).toBe(false);
+	});
+});
diff --git a/apps/api/tests/share.test.ts b/apps/api/tests/share.test.ts
new file mode 100644
index 0000000..f5fdb50
--- /dev/null
+++ b/apps/api/tests/share.test.ts
@@ -0,0 +1,144 @@
+import { describe, it, expect } from 'vitest';
+import { Hono } from 'hono';
+
+import { shareRouter } from '../src/routes/share.ts';
+import type { CardsDb } from '../src/db/connection.ts';
+
+function buildApp() {
+	const stub = {} as CardsDb;
+	const app = new Hono();
+	app.route('/api/v1/share', shareRouter({ db: stub }));
+	return { app };
+}
+
+const userA = '00000000-0000-0000-0000-00000000aaaa';
+const userB = '00000000-0000-0000-0000-00000000bbbb';
+
+function envelope(overrides: Record<string, unknown> = {}) {
+	return {
+		envelope_version: '0.1',
+		share_id: '01HZ0EJW6V6N4SM3X5RHKR8B5T', // ULID-Pattern
+		from: {
+			app: 'zitate',
+			app_version: '1.0.0',
+			user_id: userA,
+			timestamp: new Date().toISOString(),
+		},
+		to: {
+			app: 'cards',
+			user_id: userA,
+		},
+		type: 'mana/quote',
+		payload: { text: 'Lernen ohne Nachdenken ist verlorene Mühe', source: 'Konfuzius' },
+		intent: 'user_action',
+		consent_recorded_at: new Date().toISOString(),
+		...overrides,
+	};
+}
+
+describe('shareRouter — Auth-Gate', () => {
+	it('POST /receive ohne X-User-Id ist 401', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/share/receive', {
+			method: 'POST',
+			body: JSON.stringify(envelope()),
+		});
+		expect(res.status).toBe(401);
+	});
+});
+
+describe('shareRouter — Envelope-Validation', () => {
+	it('Body kein JSON → 400', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/share/receive', {
+			method: 'POST',
+			headers: { 'X-User-Id': userA, 'Content-Type': 'application/json' },
+			body: 'not-json',
+		});
+		expect(res.status).toBe(400);
+	});
+
+	it('Cross-User-Share ist 422 (envelope_invalid)', async () => {
+		const { app } = buildApp();
+		const env = envelope({
+			to: { app: 'cards', user_id: userB }, // anderer User → Cross-User
+		});
+		const res = await app.request('/api/v1/share/receive', {
+			method: 'POST',
+			headers: { 'X-User-Id': userA, 'Content-Type': 'application/json' },
+			body: JSON.stringify(env),
+		});
+		expect(res.status).toBe(422);
+		const body = (await res.json()) as { reason: string };
+		expect(body.reason).toBe('envelope_invalid');
+	});
+
+	it('User-Mismatch (envelope.to.user_id != X-User-Id) ist 403', async () => {
+		const { app } = buildApp();
+		const env = envelope({
+			from: { ...envelope().from, user_id: userB },
+			to: { app: 'cards', user_id: userB },
+		});
+		const res = await app.request('/api/v1/share/receive', {
+			method: 'POST',
+			headers: { 'X-User-Id': userA, 'Content-Type': 'application/json' },
+			body: JSON.stringify(env),
+		});
+		expect(res.status).toBe(403);
+		const body = (await res.json()) as { reason: string };
+		expect(body.reason).toBe('user_id_mismatch');
+	});
+
+	it('Wrong-Recipient (to.app != cards) ist 422', async () => {
+		const { app } = buildApp();
+		const env = envelope({ to: { app: 'memoro', user_id: userA } });
+		const res = await app.request('/api/v1/share/receive', {
+			method: 'POST',
+			headers: { 'X-User-Id': userA, 'Content-Type': 'application/json' },
+			body: JSON.stringify(env),
+		});
+		expect(res.status).toBe(422);
+		const body = (await res.json()) as { reason: string };
+		expect(body.reason).toBe('wrong_recipient');
+	});
+
+	it('Unbekannter Type ist 422', async () => {
+		const { app } = buildApp();
+		const env = envelope({ type: 'mana/unknown-thing', payload: {} });
+		const res = await app.request('/api/v1/share/receive', {
+			method: 'POST',
+			headers: { 'X-User-Id': userA, 'Content-Type': 'application/json' },
+			body: JSON.stringify(env),
+		});
+		expect(res.status).toBe(422);
+		const body = (await res.json()) as { reason: string };
+		expect(body.reason).toBe('type_not_accepted');
+	});
+
+	it('Quote-Payload ohne text ist 422', async () => {
+		const { app } = buildApp();
+		const env = envelope({ payload: { source: 'X' } });
+		const res = await app.request('/api/v1/share/receive', {
+			method: 'POST',
+			headers: { 'X-User-Id': userA, 'Content-Type': 'application/json' },
+			body: JSON.stringify(env),
+		});
+		expect(res.status).toBe(422);
+		const body = (await res.json()) as { reason: string };
+		expect(body.reason).toBe('invalid_payload');
+	});
+
+	it('Wrapped Body { envelope, delivery_token } akzeptiert', async () => {
+		const { app } = buildApp();
+		const env = envelope({ to: { app: 'memoro', user_id: userA } });
+		const res = await app.request('/api/v1/share/receive', {
+			method: 'POST',
+			headers: { 'X-User-Id': userA, 'Content-Type': 'application/json' },
+			body: JSON.stringify({ envelope: env, delivery_token: 'tok_xyz' }),
+		});
+		// Wrong-Recipient nicht 422 → Wrapper wurde korrekt unwrapped (sonst wäre es envelope_invalid)
+		expect(res.status).toBe(422);
+		const body = (await res.json()) as { reason: string };
+		expect(body.reason).toBe('wrong_recipient');
+	});
+});
diff --git a/apps/api/tests/tools.test.ts b/apps/api/tests/tools.test.ts
new file mode 100644
index 0000000..071a145
--- /dev/null
+++ b/apps/api/tests/tools.test.ts
@@ -0,0 +1,96 @@
+import { describe, it, expect } from 'vitest';
+import { Hono } from 'hono';
+
+import { toolsRouter } from '../src/routes/tools.ts';
+import type { CardsDb } from '../src/db/connection.ts';
+
+function buildApp() {
+	const stub = {
+		select: () => ({
+			from: () => ({
+				where: () => ({ limit: () => [] }),
+				innerJoin: () => ({
+					where: () => ({ orderBy: () => ({ limit: () => [] }) }),
+				}),
+			}),
+		}),
+	};
+	const app = new Hono();
+	app.route('/api/v1/tools', toolsRouter({ db: stub as unknown as CardsDb }));
+	return { app };
+}
+
+describe('toolsRouter — Auth-Gate', () => {
+	it('POST /:name ohne X-User-Id ist 401', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/tools/cards.create', {
+			method: 'POST',
+			body: '{}',
+		});
+		expect(res.status).toBe(401);
+	});
+});
+
+describe('toolsRouter — Tool-Dispatch', () => {
+	it('Unbekanntes Tool ist 404', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/tools/cards.unknown', {
+			method: 'POST',
+			headers: { 'X-User-Id': 'u-1', 'Content-Type': 'application/json' },
+			body: '{}',
+		});
+		expect(res.status).toBe(404);
+		const body = (await res.json()) as { error: string };
+		expect(body.error).toBe('unknown_tool');
+	});
+
+	it('cards.create mit invalid input ist 422', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/tools/cards.create', {
+			method: 'POST',
+			headers: { 'X-User-Id': 'u-1', 'Content-Type': 'application/json' },
+			body: '{}',
+		});
+		expect(res.status).toBe(422);
+	});
+
+	it('cards.create mit gültigem Input erreicht Deck-Lookup (404 bei stub)', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/tools/cards.create', {
+			method: 'POST',
+			headers: { 'X-User-Id': 'u-1', 'Content-Type': 'application/json' },
+			body: JSON.stringify({
+				deck_id: 'd-1',
+				type: 'basic',
+				fields: { front: 'Q', back: 'A' },
+			}),
+		});
+		expect(res.status).toBe(404);
+		const body = (await res.json()) as { error: string };
+		expect(body.error).toBe('deck_not_found');
+	});
+
+	it('cards.search ohne query ist 422', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/tools/cards.search', {
+			method: 'POST',
+			headers: { 'X-User-Id': 'u-1', 'Content-Type': 'application/json' },
+			body: '{}',
+		});
+		expect(res.status).toBe(422);
+	});
+
+	it('cards.search mit gültigem query → 200 mit envelope-Shape', async () => {
+		const { app } = buildApp();
+		const res = await app.request('/api/v1/tools/cards.search', {
+			method: 'POST',
+			headers: { 'X-User-Id': 'u-1', 'Content-Type': 'application/json' },
+			body: JSON.stringify({ query: 'Konfuzius' }),
+		});
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as { query: string; results: unknown[]; app: string };
+		expect(body.query).toBe('Konfuzius');
+		expect(Array.isArray(body.results)).toBe(true);
+		expect(body.app).toBe('cards');
+	});
+});
diff --git a/packages/cards-domain/src/index.ts b/packages/cards-domain/src/index.ts
index 92f8426..4d82e68 100644
--- a/packages/cards-domain/src/index.ts
+++ b/packages/cards-domain/src/index.ts
@@ -9,4 +9,5 @@
 
 export * from './schemas/index.ts';
 export * from './fsrs.ts';
+export * from './protocol/index.ts';
 // export * from './cloze.ts';  // Phase 8 oder später: Cloze-Parser
diff --git a/packages/cards-domain/src/protocol/envelope.ts b/packages/cards-domain/src/protocol/envelope.ts
new file mode 100644
index 0000000..ea0bc48
--- /dev/null
+++ b/packages/cards-domain/src/protocol/envelope.ts
@@ -0,0 +1,69 @@
+// TEMPORARY MIRROR von @mana/shared-share-protocol/envelope.
+//
+// Solange `pkg.mana.how` für Cards nicht erreichbar ist (NPM_AUTH_TOKEN
+// in `~/.npmrc` fehlt), halten wir die Schemas hier lokal. Sobald
+// Verdaccio offen ist, wird diese Datei gegen einen Re-Export aus
+// `@mana/shared-share-protocol` getauscht — alle Imports sind in der
+// Form `import { ShareEnvelopeSchema } from '@cards/domain'` formuliert,
+// damit der Swap eine reine 1-Liner-Edit-Aufgabe ist.
+//
+// Bei jedem Update der mana-Spec muss diese Datei nachgezogen werden,
+// bis der Swap erfolgt. Stand: 2026-05-08, ENVELOPE_VERSION 0.1.
+
+import { z } from 'zod';
+
+export const ENVELOPE_VERSION = '0.1' as const;
+
+const ULID_REGEX = /^[0-9A-HJKMNP-TV-Z]{26}$/;
+const TYPE_NAME_REGEX = /^mana\/[a-z][a-z0-9-]+$/;
+
+const SignatureSchema = z.object({
+	algorithm: z.literal('eddsa'),
+	key_id: z.string().min(1),
+	signature: z.string().min(1),
+});
+
+export const ShareEnvelopeSchema = z.object({
+	envelope_version: z.literal(ENVELOPE_VERSION),
+	share_id: z.string().regex(ULID_REGEX, 'must be ULID'),
+
+	from: z.object({
+		app: z.string().min(1),
+		app_version: z.string().min(1),
+		user_id: z.string().uuid(),
+		timestamp: z.string().datetime(),
+		instance_id: z.string().max(120).optional(),
+	}),
+
+	to: z.object({
+		app: z.string().min(1),
+		user_id: z.string().uuid(),
+	}),
+
+	type: z.string().regex(TYPE_NAME_REGEX, 'must be "mana/<kind>"'),
+	payload: z.unknown(),
+
+	source_link: z.string().max(2000).optional(),
+	user_note: z.string().max(500).optional(),
+	ttl_seconds: z.number().int().positive().optional(),
+
+	intent: z.enum(['user_action', 'automation', 'agent_tool']).default('user_action'),
+	consent_recorded_at: z.string().datetime(),
+
+	signature: SignatureSchema.optional(),
+});
+
+export type ShareEnvelope = z.infer<typeof ShareEnvelopeSchema>;
+
+/** Strict-Variante: Cross-User-Shares hart verboten. */
+export const ShareEnvelopeStrictSchema = ShareEnvelopeSchema.refine(
+	(env) => env.from.user_id === env.to.user_id,
+	{
+		message: 'cross-user shares forbidden — from.user_id must equal to.user_id',
+		path: ['to', 'user_id'],
+	}
+);
+
+export function parseEnvelope(raw: unknown) {
+	return ShareEnvelopeStrictSchema.safeParse(raw);
+}
diff --git a/packages/cards-domain/src/protocol/index.ts b/packages/cards-domain/src/protocol/index.ts
new file mode 100644
index 0000000..41275f7
--- /dev/null
+++ b/packages/cards-domain/src/protocol/index.ts
@@ -0,0 +1,7 @@
+// Public Re-Exports der lokalen Protocol-Mirror.
+// Wenn @mana/shared-share-protocol via Verdaccio verfügbar ist,
+// wird hier auf einen Re-Export aus dem npm-Paket umgestellt.
+
+export * from './envelope.ts';
+export * from './payloads.ts';
+export * from './search.ts';
diff --git a/packages/cards-domain/src/protocol/payloads.ts b/packages/cards-domain/src/protocol/payloads.ts
new file mode 100644
index 0000000..c286c02
--- /dev/null
+++ b/packages/cards-domain/src/protocol/payloads.ts
@@ -0,0 +1,83 @@
+// TEMPORARY MIRROR — siehe envelope.ts.
+//
+// Payload-Schemas für die `accepts[]` aus dem Cards-Manifest:
+// `mana/quote`, `mana/url`, `mana/text`. Andere known types
+// (`mana/transcript`, `mana/link`, `mana/note`, etc.) werden wir
+// erst ergänzen, wenn Cards sie aktiv akzeptiert.
+
+import { z } from 'zod';
+
+export const MANA_TYPE_QUOTE = 'mana/quote' as const;
+export const MANA_TYPE_URL = 'mana/url' as const;
+export const MANA_TYPE_TEXT = 'mana/text' as const;
+
+export const QuotePayloadSchema = z
+	.object({
+		text: z.string().min(1).max(8000),
+		source: z.string().max(500).optional(),
+		source_url: z.string().url().optional(),
+		source_kind: z
+			.enum(['book', 'article', 'talk', 'conversation', 'transcript', 'link', 'manual', 'other'])
+			.optional(),
+		language: z
+			.string()
+			.regex(/^[a-z]{2}(-[A-Z]{2})?$/)
+			.optional(),
+		tags: z.array(z.string().max(64)).max(50).optional(),
+	})
+	.strict();
+export type QuotePayload = z.infer<typeof QuotePayloadSchema>;
+
+/**
+ * `mana/url` — externe Web-Adresse mit optionalen OG-Metadaten.
+ * (Mana-Spec nennt dies `mana/link`. Wir akzeptieren dieselben
+ * Felder, aber unter unserem deklarierten Type-Namen `mana/url`.)
+ */
+export const UrlPayloadSchema = z
+	.object({
+		url: z.string().url(),
+		title: z.string().max(500).optional(),
+		description: z.string().max(2000).optional(),
+		snippet: z.string().max(2000).optional(),
+		image_url: z.string().url().optional(),
+		site_name: z.string().max(200).optional(),
+		favicon_url: z.string().url().optional(),
+	})
+	.strict();
+export type UrlPayload = z.infer<typeof UrlPayloadSchema>;
+
+export const TextPayloadSchema = z
+	.object({
+		text: z.string().min(1).max(50000),
+		format: z.enum(['plain', 'markdown', 'html']).default('plain'),
+		source: z.string().max(500).optional(),
+		source_url: z.string().url().optional(),
+	})
+	.strict();
+export type TextPayload = z.infer<typeof TextPayloadSchema>;
+
+/** Map vom Type-String zum Payload-Schema. */
+export const PAYLOAD_SCHEMAS = {
+	[MANA_TYPE_QUOTE]: QuotePayloadSchema,
+	[MANA_TYPE_URL]: UrlPayloadSchema,
+	[MANA_TYPE_TEXT]: TextPayloadSchema,
+} as const;
+
+export type AcceptedShareType = keyof typeof PAYLOAD_SCHEMAS;
+
+export function validatePayloadForType(
+	type: string,
+	payload: unknown
+): { success: true; data: unknown } | { success: false; error: 'unknown_type' | 'invalid_payload'; issues?: string[] } {
+	const schema = PAYLOAD_SCHEMAS[type as AcceptedShareType];
+	if (!schema) return { success: false, error: 'unknown_type' };
+	const r = schema.safeParse(payload);
+	if (!r.success) {
+		return {
+			success: false,
+			error: 'invalid_payload',
+			issues: r.error.issues.map((i) => `${i.path.join('.')}: ${i.message}`),
+		};
+	}
+	return { success: true, data: r.data };
+}
diff --git a/packages/cards-domain/src/protocol/search.ts b/packages/cards-domain/src/protocol/search.ts
new file mode 100644
index 0000000..06bebe8
--- /dev/null
+++ b/packages/cards-domain/src/protocol/search.ts
@@ -0,0 +1,39 @@
+// TEMPORARY MIRROR — siehe envelope.ts.
+
+import { z } from 'zod';
+
+export const SEARCH_ENVELOPE_VERSION = '0.1' as const;
+
+export const SearchHitSchema = z.object({
+	id: z.string().min(1),
+	type: z.string().min(1),
+	title: z.string().min(1).max(300),
+	snippet: z.string().max(1000).optional(),
+	link: z.string().min(1),
+	score: z.number().min(0).max(1),
+	highlights: z
+		.array(
+			z.object({
+				field: z.string().max(80),
+				fragment: z.string().max(500),
+			})
+		)
+		.max(10)
+		.optional(),
+	meta: z.record(z.string(), z.unknown()).optional(),
+	created_at: z.string().datetime().optional(),
+	updated_at: z.string().datetime().optional(),
+});
+export type SearchHit = z.infer<typeof SearchHitSchema>;
+
+export const SearchResultEnvelopeSchema = z.object({
+	envelope_version: z.literal(SEARCH_ENVELOPE_VERSION),
+	query: z.string().min(1).max(500),
+	app: z.string().min(1),
+	app_version: z.string().min(1),
+	results: z.array(SearchHitSchema).max(200),
+	total: z.number().int().nonnegative(),
+	partial: z.boolean(),
+	took_ms: z.number().int().nonnegative(),
+});
+export type SearchResultEnvelope = z.infer<typeof SearchResultEnvelopeSchema>;