diff --git a/packages/runtime/test/policy/client-extensions.test.ts b/packages/runtime/test/policy/client-extensions.test.ts
new file mode 100644
index 00000000..813ab518
--- /dev/null
+++ b/packages/runtime/test/policy/client-extensions.test.ts
@@ -0,0 +1,181 @@
+import { describe, expect, it } from 'vitest';
+import { definePlugin } from '../../src/client';
+import { createPolicyTestClient } from './utils';
+
+describe('client extensions tests for policies', () => {
+    it('query override one model', async () => {
+        const db = await createPolicyTestClient(
+            `
+        model Model {
+            id String @id @default(uuid())
+            x Int
+            y Int
+        
+            @@allow('read', x > 0)
+        }
+        `,
+        );
+
+        const rawDb = db.$unuseAll();
+        await rawDb.model.create({ data: { x: 0, y: 100 } });
+        await rawDb.model.create({ data: { x: 1, y: 200 } });
+        await rawDb.model.create({ data: { x: 2, y: 300 } });
+
+        const ext = definePlugin({
+            id: 'prisma-extension-queryOverride',
+            onQuery: {
+                model: {
+                    findMany({ args, query }: any) {
+                        args = args ?? {};
+                        args.where = { ...args.where, y: { lt: 300 } };
+                        return query(args);
+                    },
+                },
+            },
+        });
+
+        await expect(db.$use(ext).model.findMany()).resolves.toHaveLength(1);
+        await expect(db.$use(ext).model.findMany()).resolves.toHaveLength(1);
+    });
+
+    it('query override all models', async () => {
+        const db = await createPolicyTestClient(
+            `
+        model Model {
+            id String @id @default(uuid())
+            x Int
+            y Int
+        
+            @@allow('read', x > 0)
+        }
+        `,
+        );
+
+        const rawDb = db.$unuseAll();
+        await rawDb.model.create({ data: { x: 0, y: 100 } });
+        await rawDb.model.create({ data: { x: 1, y: 200 } });
+        await rawDb.model.create({ data: { x: 2, y: 300 } });
+
+        const ext = definePlugin({
+            id: 'prisma-extension-queryOverride',
+            onQuery: {
+                $allModels: {
+                    async findMany({ args, query }: any) {
+                        args = args ?? {};
+                        args.where = { ...args.where, y: { lt: 300 } };
+                        return query(args);
+                    },
+                },
+            },
+        });
+
+        await expect(db.$use(ext).model.findMany()).resolves.toHaveLength(1);
+        await expect(db.$use(ext).model.findMany()).resolves.toHaveLength(1);
+    });
+
+    it('query override all operations', async () => {
+        const db = await createPolicyTestClient(
+            `
+        model Model {
+            id String @id @default(uuid())
+            x Int
+            y Int
+
+            @@allow('read', x > 0)
+        }
+        `,
+        );
+
+        const rawDb = db.$unuseAll();
+        await rawDb.model.create({ data: { x: 0, y: 100 } });
+        await rawDb.model.create({ data: { x: 1, y: 200 } });
+        await rawDb.model.create({ data: { x: 2, y: 300 } });
+
+        const ext = definePlugin({
+            id: 'prisma-extension-queryOverride',
+            onQuery: {
+                model: {
+                    async $allOperations({ args, query }: any) {
+                        args = args ?? {};
+                        args.where = { ...args.where, y: { lt: 300 } };
+                        return query(args);
+                    },
+                },
+            },
+        });
+
+        await expect(db.$use(ext).model.findMany()).resolves.toHaveLength(1);
+        await expect(db.$use(ext).model.findMany()).resolves.toHaveLength(1);
+    });
+
+    it('query override everything', async () => {
+        const db = await createPolicyTestClient(
+            `
+        model Model {
+            id String @id @default(uuid())
+            x Int
+            y Int
+
+            @@allow('read', x > 0)
+        }
+        `,
+        );
+
+        const rawDb = db.$unuseAll();
+        await rawDb.model.create({ data: { x: 0, y: 100 } });
+        await rawDb.model.create({ data: { x: 1, y: 200 } });
+        await rawDb.model.create({ data: { x: 2, y: 300 } });
+
+        const ext = definePlugin({
+            id: 'prisma-extension-queryOverride',
+            onQuery: {
+                $allModels: {
+                    $allOperations({ args, query }: any) {
+                        args = args ?? {};
+                        args.where = { ...args.where, y: { lt: 300 } };
+                        return query(args);
+                    },
+                },
+            },
+        });
+
+        await expect(db.$use(ext).model.findMany()).resolves.toHaveLength(1);
+        await expect(db.$use(ext).model.findMany()).resolves.toHaveLength(1);
+    });
+
+    it('result mutation', async () => {
+        const db = await createPolicyTestClient(
+            `
+        model Model {
+            id String @id @default(uuid())
+            value Int
+
+            @@allow('read', value > 0)
+        }
+        `,
+        );
+
+        const rawDb = db.$unuseAll();
+        await rawDb.model.create({ data: { value: 0 } });
+        await rawDb.model.create({ data: { value: 1 } });
+
+        const ext = definePlugin({
+            id: 'prisma-extension-resultMutation',
+            onQuery: {
+                model: {
+                    async findMany({ args, query }: any) {
+                        const r: any = await query(args);
+                        for (let i = 0; i < r.length; i++) {
+                            r[i].value = r[i].value + 1;
+                        }
+                        return r;
+                    },
+                },
+            },
+        });
+
+        const expected = [expect.objectContaining({ value: 2 })];
+        await expect(db.$use(ext).model.findMany()).resolves.toEqual(expected);
+        await expect(db.$use(ext).model.findMany()).resolves.toEqual(expected);
+    });
+});