diff --git a/services/mana-auth/src/auth/better-auth.config.ts b/services/mana-auth/src/auth/better-auth.config.ts
index d84fc6dec..010e6e3b3 100644
--- a/services/mana-auth/src/auth/better-auth.config.ts
+++ b/services/mana-auth/src/auth/better-auth.config.ts
@@ -38,7 +38,11 @@ import {
 } from '../email/send';
 import { sourceAppStore, passwordResetRedirectStore } from './stores';
 import { TRUSTED_ORIGINS } from './sso-origins';
-import { assertValidSpaceMetadataForCreate, assertSpaceIsDeletable } from '../spaces';
+import {
+	assertValidSpaceMetadataForCreate,
+	assertSpaceIsDeletable,
+	createPersonalSpaceFor,
+} from '../spaces';
 
 // Re-export so existing imports (`import { TRUSTED_ORIGINS } from './better-auth.config'`)
 // keep working. New code should import from './sso-origins' directly.
@@ -202,6 +206,32 @@ export function createBetterAuth(databaseUrl: string) {
 			updateAge: 60 * 60 * 24, // Update session once per day
 		},
 
+		/**
+		 * Database hooks — lifecycle callbacks for core tables.
+		 *
+		 * `user.create.after` runs after a successful signup and provisions
+		 * the user's personal Space (a Better Auth organization of type
+		 * `personal`). Every user needs one because modules store private
+		 * data like mood, dreams, sleep there. Failure propagates: an
+		 * orphan user without a personal space is a worse state than a
+		 * retry-able signup error.
+		 *
+		 * See docs/plans/spaces-foundation.md and ../spaces/personal-space.ts.
+		 */
+		databaseHooks: {
+			user: {
+				create: {
+					after: async (user) => {
+						await createPersonalSpaceFor(db, {
+							id: user.id,
+							email: user.email,
+							name: user.name,
+						});
+					},
+				},
+			},
+		},
+
 		// Base URL for callbacks and redirects
 		baseURL: process.env.BASE_URL || 'http://localhost:3001',
 
diff --git a/services/mana-auth/src/spaces/index.ts b/services/mana-auth/src/spaces/index.ts
index 0de87628d..218315622 100644
--- a/services/mana-auth/src/spaces/index.ts
+++ b/services/mana-auth/src/spaces/index.ts
@@ -13,3 +13,11 @@ export {
 	assertSpaceIsDeletable,
 	buildSpaceMetadata,
 } from './metadata';
+
+export {
+	createPersonalSpaceFor,
+	candidateSlugFromEmail,
+	resolveUniqueSlug,
+	dbSlugTaken,
+	type SlugTakenLookup,
+} from './personal-space';
diff --git a/services/mana-auth/src/spaces/personal-space.spec.ts b/services/mana-auth/src/spaces/personal-space.spec.ts
new file mode 100644
index 000000000..ceb7fab10
--- /dev/null
+++ b/services/mana-auth/src/spaces/personal-space.spec.ts
@@ -0,0 +1,74 @@
+/**
+ * Tests for personal-space slug derivation and uniqueness resolution.
+ *
+ * createPersonalSpaceFor is covered by an integration test (DB-backed)
+ * once that harness exists — here we pin down the pure string logic and
+ * the slug-collision loop.
+ */
+
+import { describe, it, expect } from 'bun:test';
+import { candidateSlugFromEmail, resolveUniqueSlug, type SlugTakenLookup } from './personal-space';
+
+describe('candidateSlugFromEmail', () => {
+	it('takes the local part and lowercases it', () => {
+		expect(candidateSlugFromEmail('Till@memoro.ai')).toBe('till');
+		expect(candidateSlugFromEmail('Foo.Bar@X.de')).toBe('foo-bar');
+	});
+
+	it('strips non-alphanumerics and collapses dashes', () => {
+		expect(candidateSlugFromEmail('a..b+c@x.de')).toBe('a-b-c');
+	});
+
+	it('trims leading/trailing dashes', () => {
+		expect(candidateSlugFromEmail('--till--@x.de')).toBe('till');
+	});
+
+	it('caps at 30 characters', () => {
+		const long = 'a'.repeat(60) + '@x.de';
+		const slug = candidateSlugFromEmail(long);
+		expect(slug.length).toBeLessThanOrEqual(30);
+	});
+
+	it('falls back to a random slug when stripping empties the string', () => {
+		expect(candidateSlugFromEmail('_____@x.de')).toMatch(/^user-[a-z0-9]{6}$/);
+	});
+
+	it('falls back when local-part contains only whitespace', () => {
+		expect(candidateSlugFromEmail('  @x.de')).toMatch(/^user-[a-z0-9]{6}$/);
+	});
+
+	it('preserves digits', () => {
+		expect(candidateSlugFromEmail('user42@x.de')).toBe('user42');
+	});
+});
+
+function lookupFor(taken: string[]): SlugTakenLookup {
+	const set = new Set(taken);
+	return async (slug) => set.has(slug);
+}
+
+describe('resolveUniqueSlug', () => {
+	it('returns the base slug when free', async () => {
+		expect(await resolveUniqueSlug('till', lookupFor([]))).toBe('till');
+	});
+
+	it('appends -2 on single collision', async () => {
+		expect(await resolveUniqueSlug('till', lookupFor(['till']))).toBe('till-2');
+	});
+
+	it('walks through suffixes until free', async () => {
+		expect(await resolveUniqueSlug('till', lookupFor(['till', 'till-2', 'till-3']))).toBe('till-4');
+	});
+
+	it('skips reserved slugs even when DB says free', async () => {
+		expect(await resolveUniqueSlug('admin', lookupFor([]))).toBe('admin-2');
+		expect(await resolveUniqueSlug('api', lookupFor([]))).toBe('api-2');
+		expect(await resolveUniqueSlug('me', lookupFor([]))).toBe('me-2');
+	});
+
+	it('does NOT skip non-reserved slugs that happen to contain reserved words', async () => {
+		// We only match the exact reserved set; `admins`, `apikey`, `myself` are fine.
+		expect(await resolveUniqueSlug('admins', lookupFor([]))).toBe('admins');
+		expect(await resolveUniqueSlug('myself', lookupFor([]))).toBe('myself');
+	});
+});
diff --git a/services/mana-auth/src/spaces/personal-space.ts b/services/mana-auth/src/spaces/personal-space.ts
new file mode 100644
index 000000000..d8d3a7d01
--- /dev/null
+++ b/services/mana-auth/src/spaces/personal-space.ts
@@ -0,0 +1,153 @@
+/**
+ * Personal-Space auto-creation.
+ *
+ * Every user gets a Space of type `personal` at signup — their private
+ * default context for modules like mood, dreams, sleep, etc. This module
+ * implements the creation logic and the slug-collision handling it needs.
+ *
+ * Called from `databaseHooks.user.create.after` in better-auth.config.ts.
+ * If creation fails (e.g. a DB error), the hook propagates the error and
+ * the signup fails — orphan users without a personal space would be a
+ * worse failure mode than a retry-able signup error.
+ */
+
+import { and, eq } from 'drizzle-orm';
+import { nanoid } from 'nanoid';
+import { organizations, members } from '../db/schema/organizations';
+import type { Database } from '../db/connection';
+import { buildSpaceMetadata } from './metadata';
+
+/** Max suffix we try before giving up on collision resolution. */
+const MAX_SLUG_SUFFIX = 999;
+
+/** Slugs we never hand out — reserved for system routes or future use. */
+const RESERVED_SLUGS = new Set([
+	'me',
+	'admin',
+	'api',
+	'auth',
+	'login',
+	'logout',
+	'signup',
+	'signin',
+	'register',
+	'settings',
+	'new',
+	'app',
+	'www',
+	'support',
+	'help',
+	'billing',
+	'invite',
+]);
+
+/**
+ * Turn an email local-part (or any free-form input) into a slug candidate.
+ * Lowercase, alphanumerics + hyphens only, max 30 chars.
+ */
+export function candidateSlugFromEmail(email: string): string {
+	const localPart = email.split('@', 1)[0] ?? '';
+	const slug = localPart
+		.toLowerCase()
+		.replace(/[^a-z0-9-]+/g, '-')
+		.replace(/-+/g, '-')
+		.replace(/^-|-$/g, '')
+		.slice(0, 30);
+	// If stripping left nothing, fall back to a short random string so the
+	// caller always gets a non-empty base to work from.
+	return slug || `user-${nanoid(6).toLowerCase()}`;
+}
+
+/** Lookup function: returns true iff the given slug is already taken. */
+export type SlugTakenLookup = (slug: string) => Promise<boolean>;
+
+/**
+ * Find a free slug by appending `-2`, `-3`, … if the base is taken or
+ * reserved. Gives up after MAX_SLUG_SUFFIX attempts and falls back to a
+ * random suffix — in practice collision at that scale means something's
+ * wrong with the base generator, not real contention.
+ *
+ * Takes an injectable `isSlugTaken` function so unit tests don't need a
+ * DB. Production code uses `dbSlugTaken(db)` (below) as the adapter.
+ */
+export async function resolveUniqueSlug(
+	base: string,
+	isSlugTaken: SlugTakenLookup
+): Promise<string> {
+	const isFree = async (slug: string): Promise<boolean> => {
+		if (RESERVED_SLUGS.has(slug)) return false;
+		return !(await isSlugTaken(slug));
+	};
+
+	if (await isFree(base)) return base;
+
+	for (let i = 2; i <= MAX_SLUG_SUFFIX; i++) {
+		const candidate = `${base}-${i}`;
+		if (await isFree(candidate)) return candidate;
+	}
+
+	// Defensive fallback — should never be reached under realistic load.
+	return `${base}-${nanoid(6).toLowerCase()}`;
+}
+
+/** Adapter: turns a Drizzle db into a SlugTakenLookup. */
+export function dbSlugTaken(db: Database): SlugTakenLookup {
+	return async (slug) => {
+		const existing = await db
+			.select({ id: organizations.id })
+			.from(organizations)
+			.where(eq(organizations.slug, slug))
+			.limit(1);
+		return existing.length > 0;
+	};
+}
+
+/**
+ * Create the personal space for a freshly-registered user.
+ *
+ * Idempotent: if the user already owns a space of type `personal`, returns
+ * its id without creating a second one. Protects against accidental retry
+ * in the auth signup flow.
+ */
+export async function createPersonalSpaceFor(
+	db: Database,
+	user: { id: string; email: string; name?: string | null }
+): Promise<{ organizationId: string; slug: string; created: boolean }> {
+	// Idempotency guard — check for existing personal space via member join.
+	const existing = await db
+		.select({ orgId: organizations.id, slug: organizations.slug, metadata: organizations.metadata })
+		.from(organizations)
+		.innerJoin(members, eq(members.organizationId, organizations.id))
+		.where(eq(members.userId, user.id));
+
+	for (const row of existing) {
+		const meta = row.metadata as { type?: string } | null;
+		if (meta?.type === 'personal') {
+			return { organizationId: row.orgId, slug: row.slug ?? '', created: false };
+		}
+	}
+
+	const base = candidateSlugFromEmail(user.email);
+	const slug = await resolveUniqueSlug(base, dbSlugTaken(db));
+	const orgId = nanoid();
+	const memberId = nanoid();
+	const displayName = user.name?.trim() || user.email.split('@', 1)[0] || 'Personal';
+
+	await db.transaction(async (tx) => {
+		await tx.insert(organizations).values({
+			id: orgId,
+			name: displayName,
+			slug,
+			metadata: buildSpaceMetadata('personal'),
+			logo: null,
+		});
+		await tx.insert(members).values({
+			id: memberId,
+			organizationId: orgId,
+			userId: user.id,
+			role: 'owner',
+		});
+	});
+
+	return { organizationId: orgId, slug, created: true };
+}