diff --git a/src/svrs/auth/adapters/db.ts b/src/svrs/auth/adapters/db.ts
index 2cb73a4..5bb70a7 100644
--- a/src/svrs/auth/adapters/db.ts
+++ b/src/svrs/auth/adapters/db.ts
@@ -72,9 +72,16 @@ export function createDbAuthAdapter(repos: AuthDbRepositories): AuthStoreAdapter
 				{ consumedAt: input.nowMs }
 			),
 		revokeFlows: async (input) => {
-			const flows = await repos.flows.findMany(
-				whereOf(input)
-			);
+			// Build the where clause explicitly: forwarding `whereOf(input)`
+			// would leak `nowMs` into the predicate, which a real SQL
+			// translator turns into `WHERE now_ms = ?` and produces a
+			// silent no-op (the column doesn't exist or never matches).
+			const where: { -readonly [K in keyof typeof input]?: typeof input[K] } = {
+				tenantId: input.tenantId
+			};
+			if (input.actorRef !== undefined) where.actorRef = input.actorRef;
+			if (input.kind !== undefined) where.kind = input.kind;
+			const flows = await repos.flows.findMany(where as Readonly<Record<string, unknown>>);
 			await Promise.all(
 				flows.map((flow) => repos.flows.update({ id: flow.id }, { consumedAt: input.nowMs }))
 			);
diff --git a/src/svrs/auth/test/db-adapter-contract.test.ts b/src/svrs/auth/test/db-adapter-contract.test.ts
new file mode 100644
index 0000000..626b468
--- /dev/null
+++ b/src/svrs/auth/test/db-adapter-contract.test.ts
@@ -0,0 +1,581 @@
+/**
+ * Contract tests for `createDbAuthAdapter`. The DB adapter is the
+ * auth artifact's pluggable persistence facade — it forwards
+ * `AuthStoreAdapter` calls to a `AuthDbRepositories` injection that
+ * the application wires up against its real ORM/SQL backend.
+ *
+ * Until now the adapter only had a runtime safety test
+ * (`memory-adapter.test.ts` covers the in-memory STORE adapter, not
+ * the DB adapter facade). G4 in the codex audit deferred contract
+ * tests pending a substantial in-memory SQL fake — this file is that
+ * fake (`db-adapter-fake.ts`) plus the contract suite.
+ *
+ * Each test asserts the adapter produces the expected row state in
+ * the underlying repos. Where the adapter does cascade work
+ * (`revokeDevice`, `revokeActorSessions`, `revokeRefreshFamily`,
+ * `revokeFlows`), the cascade is verified by reading the store
+ * directly after the call returns.
+ */
+
+import { describe, expect, it } from 'vitest';
+import {
+	AUTH_AAL,
+	AUTH_AMR,
+	AUTH_CREDENTIAL_KINDS,
+	AUTH_FLOW_KINDS,
+	AUTH_REVOKE_REASONS
+} from '$libs/auth/consts';
+import { createDbAuthAdapter } from '../adapters/db.ts';
+import {
+	createMemoryAuthDbRepositories,
+	type MemoryAuthDbStore
+} from './db-adapter-fake.ts';
+import type {
+	AuthActorRef,
+	AuthCredentialId,
+	AuthDeviceId,
+	AuthFlowId,
+	AuthLinkedAccountId,
+	AuthPasswordHash,
+	AuthRefreshFamilyId,
+	AuthRefreshTokenId,
+	AuthSessionId,
+	AuthTenantId
+} from '$libs/auth/types';
+
+const TENANT_A = 'tenant-A' as AuthTenantId;
+const TENANT_B = 'tenant-B' as AuthTenantId;
+const ACTOR_A1: AuthActorRef = { tenantId: TENANT_A, actorId: 'actor-A1' as never };
+const ACTOR_A2: AuthActorRef = { tenantId: TENANT_A, actorId: 'actor-A2' as never };
+const ACTOR_B1: AuthActorRef = { tenantId: TENANT_B, actorId: 'actor-B1' as never };
+
+const NOW = 1_700_000_000_000;
+const LATER = NOW + 60_000;
+
+const HASH_PWD: AuthPasswordHash = 'argon2id$v=19$m=65536,t=2,p=1$abc' as AuthPasswordHash;
+const HASH_PWD_2: AuthPasswordHash =
+	'argon2id$v=19$m=65536,t=2,p=1$xyz' as AuthPasswordHash;
+
+function setup(): {
+	store: MemoryAuthDbStore;
+	adapter: ReturnType<typeof createDbAuthAdapter>;
+} {
+	const { store, repos } = createMemoryAuthDbRepositories();
+	return { store, adapter: createDbAuthAdapter(repos) };
+}
+
+// ── Credentials ────────────────────────────────────────────────────────
+
+describe('createDbAuthAdapter — credentials', () => {
+	it('creates a password credential and finds it by tenant + identifier', async () => {
+		const { adapter, store } = setup();
+		const created = await adapter.createPasswordCredential({
+			id: 'cred-1' as AuthCredentialId,
+			actorRef: ACTOR_A1,
+			identifierHash: 'h(alice@a.com)',
+			identifierDisplay: 'alice@a.com',
+			passwordHash: HASH_PWD,
+			nowMs: NOW
+		});
+		expect(created.kind).toBe(AUTH_CREDENTIAL_KINDS.PASSWORD);
+		expect(store.credentials.size).toBe(1);
+
+		const found = await adapter.findCredentialByIdentifier({
+			tenantId: TENANT_A,
+			kind: AUTH_CREDENTIAL_KINDS.PASSWORD,
+			identifierHash: 'h(alice@a.com)'
+		});
+		expect(found?.id).toBe('cred-1');
+	});
+
+	it('isolates credential lookups by tenant', async () => {
+		const { adapter } = setup();
+		await adapter.createPasswordCredential({
+			id: 'cred-A' as AuthCredentialId,
+			actorRef: ACTOR_A1,
+			identifierHash: 'shared',
+			identifierDisplay: 'a@x',
+			passwordHash: HASH_PWD,
+			nowMs: NOW
+		});
+		await adapter.createPasswordCredential({
+			id: 'cred-B' as AuthCredentialId,
+			actorRef: ACTOR_B1,
+			identifierHash: 'shared',
+			identifierDisplay: 'b@x',
+			passwordHash: HASH_PWD,
+			nowMs: NOW
+		});
+
+		const fromA = await adapter.findCredentialByIdentifier({
+			tenantId: TENANT_A,
+			kind: AUTH_CREDENTIAL_KINDS.PASSWORD,
+			identifierHash: 'shared'
+		});
+		expect(fromA?.id).toBe('cred-A');
+	});
+
+	it('updatePasswordCredential rotates the hash and bumps updatedAt', async () => {
+		const { adapter, store } = setup();
+		await adapter.createPasswordCredential({
+			id: 'cred-1' as AuthCredentialId,
+			actorRef: ACTOR_A1,
+			identifierHash: 'h',
+			identifierDisplay: 'a@x',
+			passwordHash: HASH_PWD,
+			nowMs: NOW
+		});
+		await adapter.updatePasswordCredential({
+			tenantId: TENANT_A,
+			credentialId: 'cred-1' as AuthCredentialId,
+			passwordHash: HASH_PWD_2,
+			nowMs: LATER
+		});
+		const row = store.credentials.get('cred-1')!;
+		expect(row.passwordHash).toBe(HASH_PWD_2);
+		expect(row.updatedAt).toBe(LATER);
+		expect(row.createdAt).toBe(NOW); // unchanged
+	});
+
+	it('updatePasswordCredential with a foreign tenant is a no-op', async () => {
+		const { adapter, store } = setup();
+		await adapter.createPasswordCredential({
+			id: 'cred-1' as AuthCredentialId,
+			actorRef: ACTOR_A1,
+			identifierHash: 'h',
+			identifierDisplay: 'a@x',
+			passwordHash: HASH_PWD,
+			nowMs: NOW
+		});
+		await adapter.updatePasswordCredential({
+			tenantId: TENANT_B, // foreign
+			credentialId: 'cred-1' as AuthCredentialId,
+			passwordHash: HASH_PWD_2,
+			nowMs: LATER
+		});
+		const row = store.credentials.get('cred-1')!;
+		expect(row.passwordHash).toBe(HASH_PWD); // unchanged
+	});
+
+	it('markCredentialVerified sets verifiedAt + updatedAt', async () => {
+		const { adapter, store } = setup();
+		await adapter.createPasswordCredential({
+			id: 'cred-1' as AuthCredentialId,
+			actorRef: ACTOR_A1,
+			identifierHash: 'h',
+			identifierDisplay: 'a@x',
+			passwordHash: HASH_PWD,
+			nowMs: NOW
+		});
+		await adapter.markCredentialVerified({
+			tenantId: TENANT_A,
+			credentialId: 'cred-1' as AuthCredentialId,
+			nowMs: LATER
+		});
+		const row = store.credentials.get('cred-1')!;
+		expect(row.verifiedAt).toBe(LATER);
+		expect(row.updatedAt).toBe(LATER);
+	});
+});
+
+// ── Flows ──────────────────────────────────────────────────────────────
+
+describe('createDbAuthAdapter — flows', () => {
+	function makeFlow(id: string, kind: typeof AUTH_FLOW_KINDS[keyof typeof AUTH_FLOW_KINDS], extra: Record<string, unknown> = {}) {
+		return {
+			id: id as AuthFlowId,
+			tenantId: TENANT_A,
+			kind,
+			expiresAt: NOW + 600_000,
+			createdAt: NOW,
+			...extra
+		};
+	}
+
+	it('createFlow + findFlowForUpdate round-trip with kind narrowing', async () => {
+		const { adapter } = setup();
+		await adapter.createFlow(makeFlow('flow-1', AUTH_FLOW_KINDS.EMAIL_VERIFICATION));
+		await adapter.createFlow(makeFlow('flow-2', AUTH_FLOW_KINDS.PASSWORD_RESET));
+
+		const matched = await adapter.findFlowForUpdate({
+			tenantId: TENANT_A,
+			flowId: 'flow-2' as AuthFlowId,
+			kind: AUTH_FLOW_KINDS.PASSWORD_RESET
+		});
+		expect(matched?.id).toBe('flow-2');
+
+		// Mismatched kind narrows away the row.
+		const wrongKind = await adapter.findFlowForUpdate({
+			tenantId: TENANT_A,
+			flowId: 'flow-2' as AuthFlowId,
+			kind: AUTH_FLOW_KINDS.EMAIL_VERIFICATION
+		});
+		expect(wrongKind).toBeNull();
+	});
+
+	it('consumeFlow stamps consumedAt', async () => {
+		const { adapter, store } = setup();
+		await adapter.createFlow(makeFlow('flow-1', AUTH_FLOW_KINDS.EMAIL_VERIFICATION));
+		await adapter.consumeFlow({
+			tenantId: TENANT_A,
+			flowId: 'flow-1' as AuthFlowId,
+			nowMs: LATER
+		});
+		expect(store.flows.get('flow-1')?.consumedAt).toBe(LATER);
+	});
+
+	it('revokeFlows scoped by tenant + actor + kind cascades to all matching rows', async () => {
+		const { adapter, store } = setup();
+		await adapter.createFlow(
+			makeFlow('flow-A1-pw1', AUTH_FLOW_KINDS.PASSWORD_RESET, { actorRef: ACTOR_A1 })
+		);
+		await adapter.createFlow(
+			makeFlow('flow-A1-pw2', AUTH_FLOW_KINDS.PASSWORD_RESET, { actorRef: ACTOR_A1 })
+		);
+		await adapter.createFlow(
+			makeFlow('flow-A1-ev', AUTH_FLOW_KINDS.EMAIL_VERIFICATION, { actorRef: ACTOR_A1 })
+		);
+		await adapter.createFlow(
+			makeFlow('flow-A2-pw', AUTH_FLOW_KINDS.PASSWORD_RESET, { actorRef: ACTOR_A2 })
+		);
+
+		await adapter.revokeFlows({
+			tenantId: TENANT_A,
+			actorRef: ACTOR_A1,
+			kind: AUTH_FLOW_KINDS.PASSWORD_RESET,
+			nowMs: LATER
+		});
+
+		// A1's two PW flows are consumed; A1's EV flow and A2's PW flow are untouched.
+		expect(store.flows.get('flow-A1-pw1')?.consumedAt).toBe(LATER);
+		expect(store.flows.get('flow-A1-pw2')?.consumedAt).toBe(LATER);
+		expect(store.flows.get('flow-A1-ev')?.consumedAt).toBeUndefined();
+		expect(store.flows.get('flow-A2-pw')?.consumedAt).toBeUndefined();
+	});
+});
+
+// ── Linked accounts ────────────────────────────────────────────────────
+
+describe('createDbAuthAdapter — linked accounts', () => {
+	it('linkAccount + findLinkedAccount round-trip scoped by tenant', async () => {
+		const { adapter } = setup();
+		await adapter.linkAccount({
+			id: 'la-1' as AuthLinkedAccountId,
+			actorRef: ACTOR_A1,
+			providerId: 'google',
+			providerKind: 'oidc',
+			providerSubject: 'sub-123',
+			email: 'alice@a.com',
+			emailVerified: true,
+			nowMs: NOW
+		});
+		const found = await adapter.findLinkedAccount({
+			tenantId: TENANT_A,
+			providerId: 'google',
+			providerSubject: 'sub-123'
+		});
+		expect(found?.id).toBe('la-1');
+
+		// Same provider+subject under a different tenant is invisible.
+		const cross = await adapter.findLinkedAccount({
+			tenantId: TENANT_B,
+			providerId: 'google',
+			providerSubject: 'sub-123'
+		});
+		expect(cross).toBeNull();
+	});
+});
+
+// ── Devices ────────────────────────────────────────────────────────────
+
+describe('createDbAuthAdapter — devices', () => {
+	it('upsertDevice inserts when missing, updates lastSeenAt when present', async () => {
+		const { adapter, store } = setup();
+		const inserted = await adapter.upsertDevice({
+			actorRef: ACTOR_A1,
+			deviceId: 'dev-1' as AuthDeviceId,
+			displayName: 'Phone',
+			nowMs: NOW
+		});
+		expect(inserted.firstSeenAt).toBe(NOW);
+		expect(inserted.lastSeenAt).toBe(NOW);
+
+		const updated = await adapter.upsertDevice({
+			actorRef: ACTOR_A1,
+			deviceId: 'dev-1' as AuthDeviceId,
+			nowMs: LATER
+		});
+		expect(updated.firstSeenAt).toBe(NOW); // unchanged
+		expect(updated.lastSeenAt).toBe(LATER);
+		expect(store.devices.size).toBe(1);
+	});
+
+	it('listDevices is scoped to actorRef', async () => {
+		const { adapter } = setup();
+		await adapter.upsertDevice({
+			actorRef: ACTOR_A1,
+			deviceId: 'dev-1' as AuthDeviceId,
+			nowMs: NOW
+		});
+		await adapter.upsertDevice({
+			actorRef: ACTOR_A2,
+			deviceId: 'dev-2' as AuthDeviceId,
+			nowMs: NOW
+		});
+		const a1 = await adapter.listDevices({ actorRef: ACTOR_A1 });
+		expect(a1.map((d) => d.id)).toEqual(['dev-1']);
+	});
+
+	it('revokeDevice cascades into active session bindings on the same device', async () => {
+		const { adapter, store } = setup();
+		await adapter.upsertDevice({
+			actorRef: ACTOR_A1,
+			deviceId: 'dev-1' as AuthDeviceId,
+			nowMs: NOW
+		});
+		await adapter.bindSession({
+			sessSessionId: 's-1' as AuthSessionId,
+			actorRef: ACTOR_A1,
+			deviceId: 'dev-1' as AuthDeviceId,
+			aal: AUTH_AAL.SINGLE_FACTOR,
+			amr: [AUTH_AMR.PASSWORD],
+			authTime: NOW,
+			createdAt: NOW
+		});
+		await adapter.bindSession({
+			sessSessionId: 's-2' as AuthSessionId,
+			actorRef: ACTOR_A1,
+			deviceId: 'dev-1' as AuthDeviceId,
+			aal: AUTH_AAL.SINGLE_FACTOR,
+			amr: [AUTH_AMR.PASSWORD],
+			authTime: NOW,
+			createdAt: NOW
+		});
+		// Independent binding on a different device — must NOT cascade.
+		await adapter.upsertDevice({
+			actorRef: ACTOR_A1,
+			deviceId: 'dev-2' as AuthDeviceId,
+			nowMs: NOW
+		});
+		await adapter.bindSession({
+			sessSessionId: 's-3' as AuthSessionId,
+			actorRef: ACTOR_A1,
+			deviceId: 'dev-2' as AuthDeviceId,
+			aal: AUTH_AAL.SINGLE_FACTOR,
+			amr: [AUTH_AMR.PASSWORD],
+			authTime: NOW,
+			createdAt: NOW
+		});
+
+		const revoked = await adapter.revokeDevice({
+			actorRef: ACTOR_A1,
+			deviceId: 'dev-1' as AuthDeviceId,
+			nowMs: LATER
+		});
+		expect(new Set(revoked)).toEqual(new Set(['s-1', 's-2']));
+		expect(store.devices.get('dev-1')?.revokedAt).toBe(LATER);
+		expect(store.sessionBindings.get('s-1')?.revokedAt).toBe(LATER);
+		expect(store.sessionBindings.get('s-1')?.revokeReason).toBe(
+			AUTH_REVOKE_REASONS.DEVICE_REVOKED
+		);
+		expect(store.sessionBindings.get('s-2')?.revokedAt).toBe(LATER);
+		expect(store.sessionBindings.get('s-3')?.revokedAt).toBeUndefined();
+	});
+});
+
+// ── Session bindings ───────────────────────────────────────────────────
+
+describe('createDbAuthAdapter — session bindings', () => {
+	async function bind(adapter: ReturnType<typeof createDbAuthAdapter>, id: string, actor: AuthActorRef = ACTOR_A1): Promise<void> {
+		await adapter.bindSession({
+			sessSessionId: id as AuthSessionId,
+			actorRef: actor,
+			aal: AUTH_AAL.SINGLE_FACTOR,
+			amr: [AUTH_AMR.PASSWORD],
+			authTime: NOW,
+			createdAt: NOW
+		});
+	}
+
+	it('bindSession + findSessionBinding round-trip', async () => {
+		const { adapter } = setup();
+		await bind(adapter, 's-1');
+		const found = await adapter.findSessionBinding({ sessSessionId: 's-1' as AuthSessionId });
+		expect(found?.actorRef.actorId).toBe(ACTOR_A1.actorId);
+	});
+
+	it('revokeSessionBinding stamps the row with reason + nowMs', async () => {
+		const { adapter, store } = setup();
+		await bind(adapter, 's-1');
+		await adapter.revokeSessionBinding({
+			sessSessionId: 's-1' as AuthSessionId,
+			nowMs: LATER,
+			reason: AUTH_REVOKE_REASONS.LOGOUT
+		});
+		const row = store.sessionBindings.get('s-1')!;
+		expect(row.revokedAt).toBe(LATER);
+		expect(row.revokeReason).toBe(AUTH_REVOKE_REASONS.LOGOUT);
+	});
+
+	it('revokeActorSessions cascades to every active binding for that actor', async () => {
+		const { adapter, store } = setup();
+		await bind(adapter, 's-A1-1', ACTOR_A1);
+		await bind(adapter, 's-A1-2', ACTOR_A1);
+		await bind(adapter, 's-A2-1', ACTOR_A2);
+
+		// Already-revoked rows must not be re-revoked.
+		await adapter.revokeSessionBinding({
+			sessSessionId: 's-A1-2' as AuthSessionId,
+			nowMs: NOW,
+			reason: AUTH_REVOKE_REASONS.LOGOUT
+		});
+
+		const closed = await adapter.revokeActorSessions({
+			actorRef: ACTOR_A1,
+			nowMs: LATER,
+			reason: AUTH_REVOKE_REASONS.PASSWORD_CHANGED
+		});
+		expect(closed).toEqual(['s-A1-1']);
+		expect(store.sessionBindings.get('s-A1-1')?.revokedAt).toBe(LATER);
+		expect(store.sessionBindings.get('s-A1-1')?.revokeReason).toBe(
+			AUTH_REVOKE_REASONS.PASSWORD_CHANGED
+		);
+		// Existing revoke timestamp is preserved (different reason, earlier ts).
+		expect(store.sessionBindings.get('s-A1-2')?.revokedAt).toBe(NOW);
+		expect(store.sessionBindings.get('s-A1-2')?.revokeReason).toBe(
+			AUTH_REVOKE_REASONS.LOGOUT
+		);
+		// Other actor untouched.
+		expect(store.sessionBindings.get('s-A2-1')?.revokedAt).toBeUndefined();
+	});
+});
+
+// ── Refresh tokens ─────────────────────────────────────────────────────
+
+describe('createDbAuthAdapter — refresh tokens', () => {
+	it('createRefreshFamily + createRefreshToken + findRefreshTokenForUpdate', async () => {
+		const { adapter } = setup();
+		await adapter.createRefreshFamily({
+			id: 'fam-1' as AuthRefreshFamilyId,
+			actorRef: ACTOR_A1,
+			sessionId: 's-1' as AuthSessionId,
+			createdAt: NOW,
+			idleExpiresAt: NOW + 600_000
+		});
+		await adapter.createRefreshToken({
+			id: 'rt-1' as AuthRefreshTokenId,
+			familyId: 'fam-1' as AuthRefreshFamilyId,
+			tokenHash: 'h(rt-1)',
+			issuedAt: NOW
+		});
+		const found = await adapter.findRefreshTokenForUpdate({ tokenHash: 'h(rt-1)' });
+		expect(found?.id).toBe('rt-1');
+	});
+
+	it('rotateRefreshToken runs in a transaction, links current → child, and returns both', async () => {
+		const { adapter, store } = setup();
+		await adapter.createRefreshFamily({
+			id: 'fam-1' as AuthRefreshFamilyId,
+			actorRef: ACTOR_A1,
+			sessionId: 's-1' as AuthSessionId,
+			createdAt: NOW,
+			idleExpiresAt: NOW + 600_000
+		});
+		await adapter.createRefreshToken({
+			id: 'rt-1' as AuthRefreshTokenId,
+			familyId: 'fam-1' as AuthRefreshFamilyId,
+			tokenHash: 'h(rt-1)',
+			issuedAt: NOW
+		});
+
+		const before = store.transactionCount;
+		const { current, child } = await adapter.rotateRefreshToken({
+			currentTokenId: 'rt-1' as AuthRefreshTokenId,
+			childToken: {
+				id: 'rt-2' as AuthRefreshTokenId,
+				familyId: 'fam-1' as AuthRefreshFamilyId,
+				tokenHash: 'h(rt-2)',
+				parentTokenId: 'rt-1' as AuthRefreshTokenId,
+				issuedAt: LATER
+			},
+			consumedAt: LATER
+		});
+		expect(store.transactionCount).toBe(before + 1);
+		expect(current.consumedAt).toBe(LATER);
+		expect(current.childTokenId).toBe('rt-2');
+		expect(child.id).toBe('rt-2');
+		// Persisted rows match the returned values.
+		expect(store.refreshTokens.get('rt-1')?.consumedAt).toBe(LATER);
+		expect(store.refreshTokens.get('rt-1')?.childTokenId).toBe('rt-2');
+		expect(store.refreshTokens.get('rt-2')?.parentTokenId).toBe('rt-1');
+	});
+
+	it('rotateRefreshToken throws when the current token is missing', async () => {
+		const { adapter } = setup();
+		await expect(
+			adapter.rotateRefreshToken({
+				currentTokenId: 'rt-missing' as AuthRefreshTokenId,
+				childToken: {
+					id: 'rt-2' as AuthRefreshTokenId,
+					familyId: 'fam-1' as AuthRefreshFamilyId,
+					tokenHash: 'h(rt-2)',
+					issuedAt: LATER
+				},
+				consumedAt: LATER
+			})
+		).rejects.toThrow();
+	});
+
+	it('revokeRefreshFamily cascades revokedAt into every token in the family', async () => {
+		const { adapter, store } = setup();
+		await adapter.createRefreshFamily({
+			id: 'fam-1' as AuthRefreshFamilyId,
+			actorRef: ACTOR_A1,
+			sessionId: 's-1' as AuthSessionId,
+			createdAt: NOW,
+			idleExpiresAt: NOW + 600_000
+		});
+		await adapter.createRefreshToken({
+			id: 'rt-1' as AuthRefreshTokenId,
+			familyId: 'fam-1' as AuthRefreshFamilyId,
+			tokenHash: 'h(rt-1)',
+			issuedAt: NOW
+		});
+		await adapter.createRefreshToken({
+			id: 'rt-2' as AuthRefreshTokenId,
+			familyId: 'fam-1' as AuthRefreshFamilyId,
+			tokenHash: 'h(rt-2)',
+			issuedAt: NOW
+		});
+		// Independent family — must not be touched.
+		await adapter.createRefreshFamily({
+			id: 'fam-2' as AuthRefreshFamilyId,
+			actorRef: ACTOR_A2,
+			sessionId: 's-2' as AuthSessionId,
+			createdAt: NOW,
+			idleExpiresAt: NOW + 600_000
+		});
+		await adapter.createRefreshToken({
+			id: 'rt-3' as AuthRefreshTokenId,
+			familyId: 'fam-2' as AuthRefreshFamilyId,
+			tokenHash: 'h(rt-3)',
+			issuedAt: NOW
+		});
+
+		await adapter.revokeRefreshFamily({
+			familyId: 'fam-1' as AuthRefreshFamilyId,
+			nowMs: LATER,
+			reason: AUTH_REVOKE_REASONS.REFRESH_REUSE
+		});
+
+		expect(store.refreshFamilies.get('fam-1')?.revokedAt).toBe(LATER);
+		expect(store.refreshFamilies.get('fam-1')?.revokeReason).toBe(
+			AUTH_REVOKE_REASONS.REFRESH_REUSE
+		);
+		expect(store.refreshTokens.get('rt-1')?.revokedAt).toBe(LATER);
+		expect(store.refreshTokens.get('rt-2')?.revokedAt).toBe(LATER);
+		// Other family + its tokens unaffected.
+		expect(store.refreshFamilies.get('fam-2')?.revokedAt).toBeUndefined();
+		expect(store.refreshTokens.get('rt-3')?.revokedAt).toBeUndefined();
+	});
+});
diff --git a/src/svrs/auth/test/db-adapter-fake.ts b/src/svrs/auth/test/db-adapter-fake.ts
new file mode 100644
index 0000000..cfa8d3e
--- /dev/null
+++ b/src/svrs/auth/test/db-adapter-fake.ts
@@ -0,0 +1,194 @@
+/**
+ * Reference implementation of `AuthDbRepositories` for the
+ * `createDbAuthAdapter` contract tests. NOT a production adapter — it
+ * runs entirely in JS Maps and skips any kind of locking / isolation.
+ *
+ * Why this is non-trivial:
+ *
+ * `db.ts` forwards `where` clauses verbatim. The README explicitly
+ * documents the conventions a real consumer must translate to SQL —
+ * see "Reglas de Produccion" + "Refresh Rotation y Locks". The fake
+ * encodes the SAME conventions:
+ *
+ *   - `{ tenantId, kind, identifierHash }` over credentials matches
+ *     `record.actorRef.tenantId`, `record.kind`, `record.identifierHash`.
+ *   - `{ flowId }` over flows matches `record.id` (label is the
+ *     adapter's user-facing name; the row column is `id`).
+ *   - `{ revokedAt: null }` matches `record.revokedAt === undefined`
+ *     (TypeScript optional fields normalize to undefined; SQL `NULL`
+ *     is the equivalent sentinel).
+ *   - `actorRef` deep-eq instead of `===`.
+ *
+ * The fake keeps state in a `MemoryAuthDbStore` so the tests can poke
+ * at intermediate row state without going through the adapter — useful
+ * for asserting cascade revocations.
+ */
+
+import type {
+	AuthCredentialRecord,
+	AuthDeviceRecord,
+	AuthFlowRecord,
+	AuthLinkedAccountRecord,
+	AuthRefreshFamilyRecord,
+	AuthRefreshTokenRecord,
+	AuthSessionBindingRecord
+} from '$libs/auth/types';
+import type { AuthDbRepositories, AuthRepository } from '../adapters/db.ts';
+
+export interface MemoryAuthDbStore {
+	readonly credentials: Map<string, AuthCredentialRecord>;
+	readonly flows: Map<string, AuthFlowRecord>;
+	readonly linkedAccounts: Map<string, AuthLinkedAccountRecord>;
+	readonly devices: Map<string, AuthDeviceRecord>;
+	readonly sessionBindings: Map<string, AuthSessionBindingRecord>;
+	readonly refreshFamilies: Map<string, AuthRefreshFamilyRecord>;
+	readonly refreshTokens: Map<string, AuthRefreshTokenRecord>;
+	transactionDepth: number;
+	transactionCount: number;
+}
+
+export function createMemoryAuthDbStore(): MemoryAuthDbStore {
+	return {
+		credentials: new Map(),
+		flows: new Map(),
+		linkedAccounts: new Map(),
+		devices: new Map(),
+		sessionBindings: new Map(),
+		refreshFamilies: new Map(),
+		refreshTokens: new Map(),
+		transactionDepth: 0,
+		transactionCount: 0
+	};
+}
+
+type WhereAliasMap = Readonly<Record<string, string>>;
+
+/**
+ * Compare a `where` clause entry against a record value, honouring the
+ * same conventions a real SQL repo would: `null` in the where matches
+ * `undefined` in the record (both are absent), and objects compare via
+ * shallow deep-equality (sufficient for `actorRef = { tenantId, actorId }`
+ * and similar tuple-shaped fields).
+ */
+function whereValueMatches(whereValue: unknown, recordValue: unknown): boolean {
+	if (whereValue === null) return recordValue === null || recordValue === undefined;
+	if (typeof whereValue === 'object' && typeof recordValue === 'object') {
+		if (whereValue === null || recordValue === null) return whereValue === recordValue;
+		const a = whereValue as Record<string, unknown>;
+		const b = recordValue as Record<string, unknown>;
+		const keys = Object.keys(a);
+		if (keys.length !== Object.keys(b).length) return false;
+		for (const key of keys) {
+			if (a[key] !== b[key]) return false;
+		}
+		return true;
+	}
+	return whereValue === recordValue;
+}
+
+function readPath(record: unknown, path: string): unknown {
+	const parts = path.split('.');
+	let cursor: unknown = record;
+	for (const part of parts) {
+		if (cursor === null || cursor === undefined) return undefined;
+		cursor = (cursor as Record<string, unknown>)[part];
+	}
+	return cursor;
+}
+
+function whereMatches<T>(
+	record: T,
+	where: Readonly<Record<string, unknown>>,
+	aliases: WhereAliasMap
+): boolean {
+	for (const [key, expected] of Object.entries(where)) {
+		if (expected === undefined) continue;
+		const path = aliases[key] ?? key;
+		const actual = readPath(record, path);
+		if (!whereValueMatches(expected, actual)) return false;
+	}
+	return true;
+}
+
+/**
+ * Build a typed `AuthRepository<T>` over a `Map<string, T>`. The
+ * `idOf` selector lets each record kind name its primary-key field —
+ * `id` for most, `sessSessionId` for session bindings.
+ */
+function createMapRepository<T>(
+	map: Map<string, T>,
+	idOf: (record: T) => string,
+	aliases: WhereAliasMap = {}
+): AuthRepository<T> {
+	return {
+		async insert(record) {
+			map.set(idOf(record), record);
+			return record;
+		},
+		async update(where, patch) {
+			for (const [key, value] of map) {
+				if (whereMatches(value, where, aliases)) {
+					map.set(key, { ...value, ...patch });
+				}
+			}
+		},
+		async findOne(where) {
+			for (const value of map.values()) {
+				if (whereMatches(value, where, aliases)) return value;
+			}
+			return null;
+		},
+		async findMany(where) {
+			const out: T[] = [];
+			for (const value of map.values()) {
+				if (whereMatches(value, where, aliases)) out.push(value);
+			}
+			return out;
+		}
+	};
+}
+
+/**
+ * Build the seven typed repos plus a transaction runner. The runner
+ * is sequential — sufficient to exercise the adapter's
+ * `repos.transaction(...)` call sites; concurrency-test fakes belong
+ * in their own module.
+ */
+export function createMemoryAuthDbRepositories(
+	store: MemoryAuthDbStore = createMemoryAuthDbStore()
+): { store: MemoryAuthDbStore; repos: AuthDbRepositories } {
+	const repos: AuthDbRepositories = {
+		credentials: createMapRepository(
+			store.credentials,
+			(r) => r.id,
+			{ tenantId: 'actorRef.tenantId' }
+		),
+		flows: createMapRepository(
+			store.flows,
+			(r) => r.id,
+			{ flowId: 'id' }
+		),
+		linkedAccounts: createMapRepository(
+			store.linkedAccounts,
+			(r) => r.id,
+			{ tenantId: 'actorRef.tenantId' }
+		),
+		devices: createMapRepository(store.devices, (r) => r.id),
+		sessionBindings: createMapRepository(
+			store.sessionBindings,
+			(r) => r.sessSessionId
+		),
+		refreshFamilies: createMapRepository(store.refreshFamilies, (r) => r.id),
+		refreshTokens: createMapRepository(store.refreshTokens, (r) => r.id),
+		async transaction(run) {
+			store.transactionDepth += 1;
+			store.transactionCount += 1;
+			try {
+				return await run();
+			} finally {
+				store.transactionDepth -= 1;
+			}
+		}
+	};
+	return { store, repos };
+}