diff --git a/shared/src/admin/admin.schema.spec.ts b/shared/src/admin/admin.schema.spec.ts
index d7b8b3303..b3b6d8a81 100644
--- a/shared/src/admin/admin.schema.spec.ts
+++ b/shared/src/admin/admin.schema.spec.ts
@@ -1,47 +1,71 @@
 import {
   adminUserCreateRequestSchema,
+  adminUserUpdateRequestSchema,
   adminPermissionsRequestSchema,
   adminInviteCreateRequestSchema,
   adminFeatureToggleRequestSchema,
+  adminTemplateNameRequestSchema,
+  adminOidcUpdateRequestSchema,
+  adminAddonUpdateRequestSchema,
+  adminCollabFeaturesRequestSchema,
+  adminNotificationPreferencesRequestSchema,
+  adminDefaultUserSettingsRequestSchema,
+  adminTestNotificationRequestSchema,
 } from './admin.schema';
 
 import { describe, it, expect } from 'vitest';
 
 describe('adminUserCreateRequestSchema', () => {
-  it('requires an email; role limited to user/admin', () => {
+  it('accepts the full body the client sends', () => {
     expect(
       adminUserCreateRequestSchema.safeParse({
+        username: 'u',
         email: 'a@b.c',
         password: 'p',
         role: 'admin',
       }).success,
     ).toBe(true);
-    expect(adminUserCreateRequestSchema.safeParse({ email: 'a@b.c' }).success).toBe(true);
-    expect(adminUserCreateRequestSchema.safeParse({ password: 'p' }).success).toBe(false);
-    expect(adminUserCreateRequestSchema.safeParse({ email: 'a@b.c', role: 'root' }).success).toBe(false);
+  });
+
+  it('leaves the missing-field and invalid-role 400s to the service', () => {
+    // All fields optional: the service answers 'Username, email and password are required'.
+    expect(adminUserCreateRequestSchema.safeParse({}).success).toBe(true);
+    // role is z.string(), not an enum: the service answers 'Invalid role'.
+    expect(adminUserCreateRequestSchema.safeParse({ email: 'a@b.c', role: 'root' }).success).toBe(true);
+  });
+
+  it('rejects wrongly-typed fields and strips unknown keys', () => {
+    expect(adminUserCreateRequestSchema.safeParse({ email: 42 }).success).toBe(false);
+    expect(adminUserCreateRequestSchema.parse({ email: 'a@b.c', extra: 1 })).toEqual({ email: 'a@b.c' });
+  });
+});
+
+describe('adminUserUpdateRequestSchema', () => {
+  it('accepts partial updates, including an empty body', () => {
+    expect(adminUserUpdateRequestSchema.safeParse({ role: 'user' }).success).toBe(true);
+    expect(adminUserUpdateRequestSchema.safeParse({}).success).toBe(true);
+    expect(adminUserUpdateRequestSchema.safeParse({ username: 5 }).success).toBe(false);
   });
 });
 
 describe('adminPermissionsRequestSchema', () => {
   it('requires a permissions record', () => {
-    expect(
-      adminPermissionsRequestSchema.safeParse({
-        permissions: { trip_edit: { user: true } },
-      }).success,
-    ).toBe(true);
+    expect(adminPermissionsRequestSchema.safeParse({ permissions: { trip_edit: 'admin' } }).success).toBe(true);
     expect(adminPermissionsRequestSchema.safeParse({}).success).toBe(false);
+    expect(adminPermissionsRequestSchema.safeParse({ permissions: null }).success).toBe(false);
+  });
+
+  it('keeps values unknown so bad levels land in the service `skipped` list, not a 400', () => {
+    expect(adminPermissionsRequestSchema.safeParse({ permissions: { trip_edit: 'nonsense' } }).success).toBe(true);
   });
 });
 
 describe('adminInviteCreateRequestSchema', () => {
-  it('accepts optional uses/expiry/role', () => {
-    expect(
-      adminInviteCreateRequestSchema.safeParse({
-        max_uses: 5,
-        expires_in_days: 7,
-      }).success,
-    ).toBe(true);
+  it('accepts optional uses/expiry/role and both number and string ids', () => {
+    expect(adminInviteCreateRequestSchema.safeParse({ max_uses: 5, expires_in_days: 7 }).success).toBe(true);
+    expect(adminInviteCreateRequestSchema.safeParse({ max_uses: '5', trip_id: '3' }).success).toBe(true);
     expect(adminInviteCreateRequestSchema.safeParse({}).success).toBe(true);
+    expect(adminInviteCreateRequestSchema.safeParse({ trip_id: null }).success).toBe(true);
     expect(adminInviteCreateRequestSchema.safeParse({ role: 'root' }).success).toBe(false);
   });
 });
@@ -50,5 +74,83 @@ describe('adminFeatureToggleRequestSchema', () => {
   it('requires a boolean enabled', () => {
     expect(adminFeatureToggleRequestSchema.safeParse({ enabled: true }).success).toBe(true);
     expect(adminFeatureToggleRequestSchema.safeParse({ enabled: 'yes' }).success).toBe(false);
+    expect(adminFeatureToggleRequestSchema.safeParse({}).success).toBe(false);
+  });
+});
+
+describe('adminTemplateNameRequestSchema', () => {
+  it('keeps name optional so the service owns the "required" 400, and strips extras', () => {
+    expect(adminTemplateNameRequestSchema.safeParse({ name: 'Beach' }).success).toBe(true);
+    expect(adminTemplateNameRequestSchema.safeParse({}).success).toBe(true);
+    expect(adminTemplateNameRequestSchema.parse({ name: 'Beach', description: 'x' })).toEqual({ name: 'Beach' });
+    expect(adminTemplateNameRequestSchema.safeParse({ name: 7 }).success).toBe(false);
+  });
+});
+
+describe('adminOidcUpdateRequestSchema', () => {
+  it('accepts the client body and strips the extra oidc_only key', () => {
+    const body = { issuer: 'https://i', client_id: 'c', display_name: 'd', discovery_url: 'u' };
+    expect(adminOidcUpdateRequestSchema.safeParse(body).success).toBe(true);
+    expect(adminOidcUpdateRequestSchema.parse({ ...body, oidc_only: false })).toEqual(body);
+    // Empty strings must survive — they are the "clear SSO config" signal.
+    expect(adminOidcUpdateRequestSchema.parse({ issuer: '', client_id: '' })).toEqual({ issuer: '', client_id: '' });
+  });
+});
+
+describe('adminAddonUpdateRequestSchema', () => {
+  it('accepts either shape and keeps config free-form', () => {
+    expect(adminAddonUpdateRequestSchema.safeParse({ enabled: true }).success).toBe(true);
+    const config = { provider: 'openai', model: 'm', apiKey: '••••', multimodal: true, nested: { a: 1 } };
+    expect(adminAddonUpdateRequestSchema.parse({ config })).toEqual({ config });
+    expect(adminAddonUpdateRequestSchema.safeParse({ enabled: 'yes' }).success).toBe(false);
+  });
+});
+
+describe('adminCollabFeaturesRequestSchema', () => {
+  it('accepts a single computed key', () => {
+    expect(adminCollabFeaturesRequestSchema.safeParse({ chat: false }).success).toBe(true);
+    expect(adminCollabFeaturesRequestSchema.safeParse({}).success).toBe(true);
+    expect(adminCollabFeaturesRequestSchema.safeParse({ polls: 'no' }).success).toBe(false);
+  });
+});
+
+describe('adminNotificationPreferencesRequestSchema', () => {
+  it('accepts arbitrary event types and channel ids, including plugin channels', () => {
+    expect(
+      adminNotificationPreferencesRequestSchema.safeParse({
+        trip_reminder: { email: true, 'plugin:acme': false },
+      }).success,
+    ).toBe(true);
+    expect(adminNotificationPreferencesRequestSchema.safeParse({}).success).toBe(true);
+    expect(adminNotificationPreferencesRequestSchema.safeParse({ x: { email: 'yes' } }).success).toBe(false);
+  });
+});
+
+describe('adminDefaultUserSettingsRequestSchema', () => {
+  it('keeps null as the reset sentinel and rejects non-objects', () => {
+    expect(adminDefaultUserSettingsRequestSchema.parse({ theme: 'dark', density: null, compact: true })).toEqual({
+      theme: 'dark',
+      density: null,
+      compact: true,
+    });
+    expect(adminDefaultUserSettingsRequestSchema.safeParse([]).success).toBe(false);
+    expect(adminDefaultUserSettingsRequestSchema.safeParse(null).success).toBe(false);
+  });
+});
+
+describe('adminTestNotificationRequestSchema', () => {
+  it('accepts an empty body and both inApp shapes', () => {
+    expect(adminTestNotificationRequestSchema.safeParse({}).success).toBe(true);
+    expect(adminTestNotificationRequestSchema.safeParse({ event: 'trip_reminder', inApp: true }).success).toBe(true);
+    expect(
+      adminTestNotificationRequestSchema.safeParse({
+        event: 'x',
+        scope: 'admin',
+        targetId: 1,
+        params: { a: 'b' },
+        inApp: { type: 'boolean', positiveCallback: { action: 'test_approve', payload: {} } },
+      }).success,
+    ).toBe(true);
+    expect(adminTestNotificationRequestSchema.safeParse({ targetId: 'one' }).success).toBe(false);
   });
 });
diff --git a/shared/src/admin/admin.schema.ts b/shared/src/admin/admin.schema.ts
index 08c54b315..d0482557e 100644
--- a/shared/src/admin/admin.schema.ts
+++ b/shared/src/admin/admin.schema.ts
@@ -3,31 +3,49 @@ import { z } from 'zod';
 /**
  * Admin API contract for /api/admin (admin-only).
  *
- * The admin service validates most bodies itself (returning {error,status}), so
- * these schemas pin the well-defined ones: user create/update, the permission
- * matrix, invites and the boolean feature toggles. Free-form bodies (OIDC
- * settings, addon config, default user settings) stay with the service.
+ * These schemas exist to satisfy the body-contract ratchet without changing
+ * behavior, so they are deliberately permissive: wherever AdminService already
+ * emits a bespoke 400 of its own ('Invalid role', 'Name is required',
+ * 'Username, email and password are required'), the field stays optional and
+ * loosely typed so that error survives byte-identically. Every object schema is
+ * non-strict — several clients and tests send extra keys and expect success.
  */
+
 export const adminUserCreateRequestSchema = z.object({
-  email: z.string(),
-  password: z.string().optional(),
   username: z.string().optional(),
-  role: z.enum(['user', 'admin']).optional(),
+  email: z.string().optional(),
+  password: z.string().optional(),
+  // Deliberately z.string(), not z.enum: the service's own 'Invalid role' 400
+  // is the pinned contract for a bad role.
+  role: z.string().optional(),
 });
 export type AdminUserCreateRequest = z.infer<typeof adminUserCreateRequestSchema>;
 
+export const adminUserUpdateRequestSchema = z.object({
+  username: z.string().optional(),
+  email: z.string().optional(),
+  password: z.string().optional(),
+  role: z.string().optional(),
+});
+export type AdminUserUpdateRequest = z.infer<typeof adminUserUpdateRequestSchema>;
+
+// Values stay z.unknown(): PermissionsService.savePermissions reports unknown
+// levels through its `skipped` list (a 200 response field the admin UI shows),
+// so narrowing to z.string() would turn that into a 400.
 export const adminPermissionsRequestSchema = z.object({
   permissions: z.record(z.string(), z.unknown()),
 });
 export type AdminPermissionsRequest = z.infer<typeof adminPermissionsRequestSchema>;
 
 export const adminInviteCreateRequestSchema = z.object({
-  max_uses: z.number().optional(),
-  expires_in_days: z.number().optional(),
+  // string | number: the service parses with parseInt(String(x)), and the
+  // admin UI sends numbers while older clients sent strings.
+  max_uses: z.union([z.number(), z.string()]).optional(),
+  expires_in_days: z.union([z.number(), z.string()]).optional(),
   role: z.enum(['user', 'admin']).optional(),
   // Optional trip binding (#1402): a user who registers via the link is
   // auto-added to this trip. Nullable/absent = a plain registration invite.
-  trip_id: z.number().int().positive().nullable().optional(),
+  trip_id: z.union([z.number(), z.string()]).nullable().optional(),
 });
 export type AdminInviteCreateRequest = z.infer<typeof adminInviteCreateRequestSchema>;
 
@@ -35,3 +53,60 @@ export const adminFeatureToggleRequestSchema = z.object({
   enabled: z.boolean(),
 });
 export type AdminFeatureToggleRequest = z.infer<typeof adminFeatureToggleRequestSchema>;
+
+// Shared by all six packing-template create/update routes. `name` is optional so
+// the service's 'Name is required' / 'Category name is required' / 'Item name is
+// required' 400s stay the contract, and so the update routes keep treating a
+// blank name as a no-op.
+export const adminTemplateNameRequestSchema = z.object({
+  name: z.string().optional(),
+});
+export type AdminTemplateNameRequest = z.infer<typeof adminTemplateNameRequestSchema>;
+
+export const adminOidcUpdateRequestSchema = z.object({
+  issuer: z.string().optional(),
+  client_id: z.string().optional(),
+  client_secret: z.string().optional(),
+  display_name: z.string().optional(),
+  discovery_url: z.string().optional(),
+});
+export type AdminOidcUpdateRequest = z.infer<typeof adminOidcUpdateRequestSchema>;
+
+// `config` must stay free-form: each addon stores its own keys, and the AI addon
+// round-trips an apiKey mask sentinel that a narrower shape would strip.
+export const adminAddonUpdateRequestSchema = z.object({
+  enabled: z.boolean().optional(),
+  config: z.record(z.string(), z.unknown()).optional(),
+});
+export type AdminAddonUpdateRequest = z.infer<typeof adminAddonUpdateRequestSchema>;
+
+// Fully partial — the client PUTs one computed key at a time.
+export const adminCollabFeaturesRequestSchema = z.object({
+  chat: z.boolean().optional(),
+  notes: z.boolean().optional(),
+  polls: z.boolean().optional(),
+  whatsnext: z.boolean().optional(),
+});
+export type AdminCollabFeaturesRequest = z.infer<typeof adminCollabFeaturesRequestSchema>;
+
+// event type -> channel id -> enabled. Anything narrower would silently drop
+// plugin-contributed channels, since the client echoes back the whole matrix.
+export const adminNotificationPreferencesRequestSchema = z.record(z.string(), z.record(z.string(), z.boolean()));
+export type AdminNotificationPreferencesRequest = z.infer<typeof adminNotificationPreferencesRequestSchema>;
+
+// Heterogeneous values, and `null` is meaningful — SettingsService treats it as
+// "reset to the built-in default". z.record also rejects arrays and null bodies,
+// preserving the route's object-only guard.
+export const adminDefaultUserSettingsRequestSchema = z.record(z.string(), z.unknown());
+export type AdminDefaultUserSettingsRequest = z.infer<typeof adminDefaultUserSettingsRequestSchema>;
+
+// Dev-only test sender: every field optional (callers POST {}), and `inApp` is a
+// boolean OR the in-app action descriptor the dev panel sends.
+export const adminTestNotificationRequestSchema = z.object({
+  event: z.string().optional(),
+  scope: z.string().optional(),
+  targetId: z.number().optional(),
+  params: z.record(z.string(), z.unknown()).optional(),
+  inApp: z.union([z.boolean(), z.record(z.string(), z.unknown())]).optional(),
+});
+export type AdminTestNotificationRequest = z.infer<typeof adminTestNotificationRequestSchema>;