diff --git a/package.json b/package.json
index c88ee776..1c0ec9ae 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "zenstack-v3",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "ZenStack",
     "packageManager": "pnpm@10.12.1",
     "scripts": {
diff --git a/packages/cli/package.json b/packages/cli/package.json
index 69214b57..1d4c8d69 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -3,7 +3,7 @@
     "publisher": "zenstack",
     "displayName": "ZenStack CLI",
     "description": "FullStack database toolkit with built-in access control and automatic API generation.",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "type": "module",
     "author": {
         "name": "ZenStack Team"
diff --git a/packages/common-helpers/package.json b/packages/common-helpers/package.json
index 9e4fae3e..72c236a2 100644
--- a/packages/common-helpers/package.json
+++ b/packages/common-helpers/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@zenstackhq/common-helpers",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "ZenStack Common Helpers",
     "type": "module",
     "scripts": {
diff --git a/packages/create-zenstack/package.json b/packages/create-zenstack/package.json
index e1fb4fa5..6e4c5b5b 100644
--- a/packages/create-zenstack/package.json
+++ b/packages/create-zenstack/package.json
@@ -1,6 +1,6 @@
 {
     "name": "create-zenstack",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "Create a new ZenStack project",
     "type": "module",
     "scripts": {
diff --git a/packages/dialects/sql.js/package.json b/packages/dialects/sql.js/package.json
index df6765ae..cd15a02a 100644
--- a/packages/dialects/sql.js/package.json
+++ b/packages/dialects/sql.js/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@zenstackhq/kysely-sql-js",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "Kysely dialect for sql.js",
     "type": "module",
     "scripts": {
diff --git a/packages/eslint-config/package.json b/packages/eslint-config/package.json
index d061db42..957042e4 100644
--- a/packages/eslint-config/package.json
+++ b/packages/eslint-config/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@zenstackhq/eslint-config",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "type": "module",
     "private": true,
     "license": "MIT"
diff --git a/packages/ide/vscode/package.json b/packages/ide/vscode/package.json
index d8472cc3..0359609b 100644
--- a/packages/ide/vscode/package.json
+++ b/packages/ide/vscode/package.json
@@ -1,7 +1,7 @@
 {
     "name": "zenstack",
     "publisher": "zenstack",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "displayName": "ZenStack Language Tools",
     "description": "VSCode extension for ZenStack ZModel language",
     "private": true,
diff --git a/packages/language/package.json b/packages/language/package.json
index 8e0c1585..e7797f08 100644
--- a/packages/language/package.json
+++ b/packages/language/package.json
@@ -1,7 +1,7 @@
 {
     "name": "@zenstackhq/language",
     "description": "ZenStack ZModel language specification",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "license": "MIT",
     "author": "ZenStack Team",
     "files": [
diff --git a/packages/runtime/package.json b/packages/runtime/package.json
index ab3a8b1c..401e064f 100644
--- a/packages/runtime/package.json
+++ b/packages/runtime/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@zenstackhq/runtime",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "ZenStack Runtime",
     "type": "module",
     "scripts": {
diff --git a/packages/runtime/src/client/crud-types.ts b/packages/runtime/src/client/crud-types.ts
index b41cf728..728082d7 100644
--- a/packages/runtime/src/client/crud-types.ts
+++ b/packages/runtime/src/client/crud-types.ts
@@ -631,16 +631,15 @@ export type FindArgs<
           skip?: number;
           take?: number;
           orderBy?: OrArray<OrderBy<Schema, Model, true, false>>;
-      }
+      } & Distinct<Schema, Model> &
+          Cursor<Schema, Model>
     : {}) &
     (AllowFilter extends true
         ? {
               where?: WhereInput<Schema, Model>;
           }
         : {}) &
-    SelectIncludeOmit<Schema, Model, Collection> &
-    Distinct<Schema, Model> &
-    Cursor<Schema, Model>;
+    SelectIncludeOmit<Schema, Model, Collection>;
 
 export type FindManyArgs<Schema extends SchemaDef, Model extends GetModels<Schema>> = FindArgs<Schema, Model, true>;
 export type FindFirstArgs<Schema extends SchemaDef, Model extends GetModels<Schema>> = FindArgs<Schema, Model, false>;
diff --git a/packages/runtime/src/client/crud/operations/base.ts b/packages/runtime/src/client/crud/operations/base.ts
index 24874d69..f11ad80c 100644
--- a/packages/runtime/src/client/crud/operations/base.ts
+++ b/packages/runtime/src/client/crud/operations/base.ts
@@ -68,6 +68,8 @@ export type CrudOperation =
     | 'aggregate'
     | 'groupBy';
 
+export type AllCrudOperation = CrudOperation | 'findUniqueOrThrow' | 'findFirstOrThrow';
+
 export type FromRelationContext<Schema extends SchemaDef> = {
     model: GetModels<Schema>;
     field: string;
diff --git a/packages/runtime/src/client/crud/validator.ts b/packages/runtime/src/client/crud/validator.ts
index 5b660aee..be83d102 100644
--- a/packages/runtime/src/client/crud/validator.ts
+++ b/packages/runtime/src/client/crud/validator.ts
@@ -44,7 +44,7 @@ export class InputValidator<Schema extends SchemaDef> {
         return this.validate<FindArgs<Schema, GetModels<Schema>, true>, Parameters<typeof this.makeFindSchema>[1]>(
             model,
             'find',
-            { unique, collection: true },
+            { unique },
             (model, options) => this.makeFindSchema(model, options),
             args,
         );
@@ -196,7 +196,7 @@ export class InputValidator<Schema extends SchemaDef> {
 
     // #region Find
 
-    private makeFindSchema(model: string, options: { unique: boolean; collection: boolean }) {
+    private makeFindSchema(model: string, options: { unique: boolean }) {
         const fields: Record<string, z.ZodSchema> = {};
         const where = this.makeWhereSchema(model, options.unique);
         if (options.unique) {
@@ -208,13 +208,13 @@ export class InputValidator<Schema extends SchemaDef> {
         fields['select'] = this.makeSelectSchema(model).optional();
         fields['include'] = this.makeIncludeSchema(model).optional();
         fields['omit'] = this.makeOmitSchema(model).optional();
-        fields['distinct'] = this.makeDistinctSchema(model).optional();
-        fields['cursor'] = this.makeCursorSchema(model).optional();
 
-        if (options.collection) {
+        if (!options.unique) {
             fields['skip'] = this.makeSkipSchema().optional();
             fields['take'] = this.makeTakeSchema().optional();
             fields['orderBy'] = this.orArray(this.makeOrderBySchema(model, true, false), true).optional();
+            fields['cursor'] = this.makeCursorSchema(model).optional();
+            fields['distinct'] = this.makeDistinctSchema(model).optional();
         }
 
         let result: ZodType = z.strictObject(fields);
@@ -589,15 +589,7 @@ export class InputValidator<Schema extends SchemaDef> {
         for (const field of Object.keys(modelDef.fields)) {
             const fieldDef = requireField(this.schema, model, field);
             if (fieldDef.relation) {
-                fields[field] = z
-                    .union([
-                        z.literal(true),
-                        z.strictObject({
-                            select: z.lazy(() => this.makeSelectSchema(fieldDef.type)).optional(),
-                            include: z.lazy(() => this.makeIncludeSchema(fieldDef.type)).optional(),
-                        }),
-                    ])
-                    .optional();
+                fields[field] = this.makeRelationSelectIncludeSchema(fieldDef).optional();
             } else {
                 fields[field] = z.boolean().optional();
             }
@@ -634,6 +626,33 @@ export class InputValidator<Schema extends SchemaDef> {
         return z.strictObject(fields);
     }
 
+    private makeRelationSelectIncludeSchema(fieldDef: FieldDef) {
+        return z.union([
+            z.boolean(),
+            z.strictObject({
+                ...(fieldDef.array || fieldDef.optional
+                    ? {
+                          // to-many relations and optional to-one relations are filterable
+                          where: z.lazy(() => this.makeWhereSchema(fieldDef.type, false)).optional(),
+                      }
+                    : {}),
+                select: z.lazy(() => this.makeSelectSchema(fieldDef.type)).optional(),
+                include: z.lazy(() => this.makeIncludeSchema(fieldDef.type)).optional(),
+                omit: z.lazy(() => this.makeOmitSchema(fieldDef.type)).optional(),
+                ...(fieldDef.array
+                    ? {
+                          // to-many relations can be ordered, skipped, taken, and cursor-located
+                          orderBy: z.lazy(() => this.makeOrderBySchema(fieldDef.type, true, false)).optional(),
+                          skip: this.makeSkipSchema().optional(),
+                          take: this.makeTakeSchema().optional(),
+                          cursor: this.makeCursorSchema(fieldDef.type).optional(),
+                          distinct: this.makeDistinctSchema(fieldDef.type).optional(),
+                      }
+                    : {}),
+            }),
+        ]);
+    }
+
     private makeOmitSchema(model: string) {
         const modelDef = requireModel(this.schema, model);
         const fields: Record<string, ZodType> = {};
@@ -652,21 +671,7 @@ export class InputValidator<Schema extends SchemaDef> {
         for (const field of Object.keys(modelDef.fields)) {
             const fieldDef = requireField(this.schema, model, field);
             if (fieldDef.relation) {
-                fields[field] = z
-                    .union([
-                        z.literal(true),
-                        z.strictObject({
-                            select: z.lazy(() => this.makeSelectSchema(fieldDef.type)).optional(),
-                            include: z.lazy(() => this.makeIncludeSchema(fieldDef.type)).optional(),
-                            omit: z.lazy(() => this.makeOmitSchema(fieldDef.type)).optional(),
-                            where: z.lazy(() => this.makeWhereSchema(fieldDef.type, false)).optional(),
-                            orderBy: z.lazy(() => this.makeOrderBySchema(fieldDef.type, true, false)).optional(),
-                            skip: this.makeSkipSchema().optional(),
-                            take: this.makeTakeSchema().optional(),
-                            distinct: this.makeDistinctSchema(fieldDef.type).optional(),
-                        }),
-                    ])
-                    .optional();
+                fields[field] = this.makeRelationSelectIncludeSchema(fieldDef).optional();
             }
         }
 
diff --git a/packages/runtime/src/client/plugin.ts b/packages/runtime/src/client/plugin.ts
index 7f087a5d..99ee2d92 100644
--- a/packages/runtime/src/client/plugin.ts
+++ b/packages/runtime/src/client/plugin.ts
@@ -2,7 +2,7 @@ import type { OperationNode, QueryResult, RootOperationNode, UnknownRow } from '
 import type { ClientContract, ToKysely } from '.';
 import type { GetModels, SchemaDef } from '../schema';
 import type { MaybePromise } from '../utils/type-utils';
-import type { CrudOperation } from './crud/operations/base';
+import type { AllCrudOperation } from './crud/operations/base';
 
 /**
  * ZenStack runtime plugin.
@@ -61,7 +61,7 @@ type OnQueryHookContext<Schema extends SchemaDef> = {
     /**
      * The operation that is being performed.
      */
-    operation: CrudOperation;
+    operation: AllCrudOperation;
 
     /**
      * The query arguments.
diff --git a/packages/runtime/test/client-api/find.test.ts b/packages/runtime/test/client-api/find.test.ts
index 9b588a03..70cc400c 100644
--- a/packages/runtime/test/client-api/find.test.ts
+++ b/packages/runtime/test/client-api/find.test.ts
@@ -637,6 +637,97 @@ describe.each(createClientSpecs(PG_DB_NAME))('Client find tests for $provider',
         expect(r?.posts[0]?.createdAt).toBeInstanceOf(Date);
         expect(r?.posts[0]?.published).toBeTypeOf('boolean');
 
+        await expect(
+            client.user.findUnique({
+                where: { id: user.id },
+                select: {
+                    posts: { where: { published: true }, select: { title: true }, orderBy: { createdAt: 'desc' } },
+                },
+            }),
+        ).resolves.toMatchObject({
+            posts: [expect.objectContaining({ title: 'Post1' })],
+        });
+        await expect(
+            client.user.findUnique({
+                where: { id: user.id },
+                include: {
+                    posts: { where: { published: true }, select: { title: true }, orderBy: { createdAt: 'desc' } },
+                },
+            }),
+        ).resolves.toMatchObject({
+            posts: [expect.objectContaining({ title: 'Post1' })],
+        });
+
+        await expect(
+            client.user.findUnique({
+                where: { id: user.id },
+                select: {
+                    posts: { orderBy: { title: 'asc' }, skip: 1, take: 1, distinct: ['title'] },
+                },
+            }),
+        ).resolves.toMatchObject({
+            posts: [expect.objectContaining({ title: 'Post2' })],
+        });
+        await expect(
+            client.user.findUnique({
+                where: { id: user.id },
+                include: {
+                    posts: { orderBy: { title: 'asc' }, skip: 1, take: 1, distinct: ['title'] },
+                },
+            }),
+        ).resolves.toMatchObject({
+            posts: [expect.objectContaining({ title: 'Post2' })],
+        });
+
+        await expect(
+            client.post.findFirst({
+                select: { author: { select: { email: true } } },
+            }),
+        ).resolves.toMatchObject({
+            author: { email: expect.any(String) },
+        });
+        await expect(
+            client.post.findFirst({
+                include: { author: { select: { email: true } } },
+            }),
+        ).resolves.toMatchObject({
+            author: { email: expect.any(String) },
+        });
+
+        await expect(
+            client.user.findUnique({
+                where: { id: user.id },
+                select: {
+                    profile: { where: { bio: 'My bio' } },
+                },
+            }),
+        ).resolves.toMatchObject({ profile: expect.any(Object) });
+        await expect(
+            client.user.findUnique({
+                where: { id: user.id },
+                include: {
+                    profile: { where: { bio: 'My bio' } },
+                },
+            }),
+        ).resolves.toMatchObject({ profile: expect.any(Object) });
+
+        await expect(
+            client.user.findUnique({
+                where: { id: user.id },
+                select: {
+                    profile: { where: { bio: 'Other bio' } },
+                },
+            }),
+        ).resolves.toMatchObject({ profile: null });
+        await expect(
+            client.user.findUnique({
+                where: { id: user.id },
+                include: {
+                    profile: { where: { bio: 'Other bio' } },
+                },
+            }),
+        ).resolves.toMatchObject({ profile: null });
+
         await expect(
             client.user.findUnique({
                 where: { id: user.id },
@@ -778,7 +869,7 @@ describe.each(createClientSpecs(PG_DB_NAME))('Client find tests for $provider',
                 // @ts-expect-error
                 include: { author: { where: { email: user.email } } },
             }),
-        ).rejects.toThrow(`Field "author" doesn't support filtering`);
+        ).rejects.toThrow(`Invalid find args`);
 
         // sorting
         let u = await client.user.findUniqueOrThrow({
diff --git a/packages/sdk/package.json b/packages/sdk/package.json
index 21dec84f..98105ecc 100644
--- a/packages/sdk/package.json
+++ b/packages/sdk/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@zenstackhq/sdk",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "ZenStack SDK",
     "type": "module",
     "scripts": {
diff --git a/packages/tanstack-query/package.json b/packages/tanstack-query/package.json
index c680ae18..0c983361 100644
--- a/packages/tanstack-query/package.json
+++ b/packages/tanstack-query/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@zenstackhq/tanstack-query",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "",
     "main": "index.js",
     "type": "module",
diff --git a/packages/testtools/package.json b/packages/testtools/package.json
index 80d9bcf1..216a916d 100644
--- a/packages/testtools/package.json
+++ b/packages/testtools/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@zenstackhq/testtools",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "ZenStack Test Tools",
     "type": "module",
     "scripts": {
diff --git a/packages/typescript-config/package.json b/packages/typescript-config/package.json
index 5fd89dd4..5a51d6b9 100644
--- a/packages/typescript-config/package.json
+++ b/packages/typescript-config/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@zenstackhq/typescript-config",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "private": true,
     "license": "MIT"
 }
diff --git a/packages/vitest-config/package.json b/packages/vitest-config/package.json
index d259c676..516ab27c 100644
--- a/packages/vitest-config/package.json
+++ b/packages/vitest-config/package.json
@@ -1,7 +1,7 @@
 {
     "name": "@zenstackhq/vitest-config",
     "type": "module",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "private": true,
     "license": "MIT",
     "exports": {
diff --git a/packages/zod/package.json b/packages/zod/package.json
index 066824d6..b40b2b24 100644
--- a/packages/zod/package.json
+++ b/packages/zod/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@zenstackhq/zod",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "",
     "type": "module",
     "main": "index.js",
diff --git a/samples/blog/package.json b/samples/blog/package.json
index 469161b5..8dfec300 100644
--- a/samples/blog/package.json
+++ b/samples/blog/package.json
@@ -1,6 +1,6 @@
 {
     "name": "sample-blog",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "description": "",
     "main": "index.js",
     "scripts": {
diff --git a/tests/e2e/package.json b/tests/e2e/package.json
index a08dfe41..928f1127 100644
--- a/tests/e2e/package.json
+++ b/tests/e2e/package.json
@@ -1,6 +1,6 @@
 {
     "name": "e2e",
-    "version": "3.0.0-alpha.25",
+    "version": "3.0.0-alpha.26",
     "private": true,
     "type": "module",
     "scripts": {