From 44311e145ef0031ada4f6c2a300401f9973f8769 Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 10:59:49 -0800
Subject: [PATCH 01/13] Add a reproduction of the issue

---
 convex/_generated/api.d.ts             |  2 ++
 convex/zodFunctionsExample.ts          | 36 ++++++++++++++++++++++
 src/App.tsx                            |  2 ++
 src/components/ZodFunctionsExample.tsx | 42 ++++++++++++++++++++++++++
 4 files changed, 82 insertions(+)
 create mode 100644 convex/zodFunctionsExample.ts
 create mode 100644 src/components/ZodFunctionsExample.tsx

diff --git a/convex/_generated/api.d.ts b/convex/_generated/api.d.ts
index 9b59dec8..c697261a 100644
--- a/convex/_generated/api.d.ts
+++ b/convex/_generated/api.d.ts
@@ -19,6 +19,7 @@ import type * as sessionsExample from "../sessionsExample.js";
 import type * as streamsExample from "../streamsExample.js";
 import type * as testingFunctions from "../testingFunctions.js";
 import type * as triggersExample from "../triggersExample.js";
+import type * as zodFunctionsExample from "../zodFunctionsExample.js";
 
 import type {
   ApiFromModules,
@@ -38,6 +39,7 @@ declare const fullApi: ApiFromModules<{
   streamsExample: typeof streamsExample;
   testingFunctions: typeof testingFunctions;
   triggersExample: typeof triggersExample;
+  zodFunctionsExample: typeof zodFunctionsExample;
 }>;
 
 /**
diff --git a/convex/zodFunctionsExample.ts b/convex/zodFunctionsExample.ts
new file mode 100644
index 00000000..479693d2
--- /dev/null
+++ b/convex/zodFunctionsExample.ts
@@ -0,0 +1,36 @@
+import { zCustomQuery } from "convex-helpers/server/zod4";
+import { query } from "./_generated/server";
+import { NoOp } from "convex-helpers/server/customFunctions";
+import { z } from "zod/v4";
+
+export const zQuery = zCustomQuery(query, NoOp);
+
+export const noArgs = zQuery({
+  args: {},
+  handler: async (ctx) => {
+    return "Hello world!";
+  },
+});
+
+const stringToDate = z.codec(z.iso.datetime(), z.date(), {
+  decode: (isoString) => new Date(isoString),
+  encode: (date) => date.toISOString(),
+});
+const dateToString = z.codec(z.date(), z.iso.datetime(), {
+  decode: (date) => date.toISOString(),
+  encode: (isoString) => new Date(isoString),
+});
+
+export const withArgs = zQuery({
+  args: {
+    date: stringToDate,
+  },
+  returns: {
+    oneDayAfter: dateToString,
+  },
+  handler: async (_ctx, args) => {
+    return {
+      oneDayAfter: new Date(args.date.getTime() + 24 * 60 * 60 * 1000),
+    };
+  },
+});
diff --git a/src/App.tsx b/src/App.tsx
index 1ae0ef4b..9f8cf60d 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -3,6 +3,7 @@ import RelationshipExample from "./components/RelationshipExample";
 import SessionsExample from "./components/SessionsExample";
 import { HonoExample } from "./components/HonoExample";
 import { StreamsExample } from "./components/StreamsExample";
+import { ZodFunctionsExample } from "./components/ZodFunctionsExample";
 import { SessionProvider } from "convex-helpers/react/sessions";
 import { CacheExample } from "./components/CacheExample";
 import { ConvexQueryCacheProvider } from "convex-helpers/react/cache";
@@ -23,6 +24,7 @@ export default function App() {
           <HonoExample />
           <CacheExample />
           <StreamsExample />
+          <ZodFunctionsExample />
         </ConvexQueryCacheProvider>
       </SessionProvider>
     </main>
diff --git a/src/components/ZodFunctionsExample.tsx b/src/components/ZodFunctionsExample.tsx
new file mode 100644
index 00000000..86714800
--- /dev/null
+++ b/src/components/ZodFunctionsExample.tsx
@@ -0,0 +1,42 @@
+import { api } from "../../convex/_generated/api";
+import { useQuery } from "convex/react";
+import { useMemo } from "react";
+import { z } from "zod/v4";
+
+const stringToDate = z.codec(z.iso.datetime(), z.date(), {
+  decode: (isoString) => new Date(isoString),
+  encode: (date) => date.toISOString(),
+});
+
+export function ZodFunctionsExample() {
+  const now = useMemo(() => new Date(), []);
+
+  const noArgsResult = useQuery(api.zodFunctionsExample.noArgs);
+  const noArgsResultEmptyArgs = useQuery(api.zodFunctionsExample.noArgs, {});
+  const withArgsResult = useQuery(api.zodFunctionsExample.withArgs, {
+    date: stringToDate.encode(now),
+  });
+
+  return (
+    <div>
+      <h2>Zod Functions Example</h2>
+      <section>
+        <h3>No Args Query</h3>
+        <p>Result: {noArgsResult ?? "Loading..."}</p>
+      </section>
+      <section>
+        <h3>No Args Query (Empty Args)</h3>
+        <p>Result: {noArgsResultEmptyArgs ?? "Loading..."}</p>
+      </section>
+      <section>
+        <h3>With Args Query</h3>
+        {withArgsResult && (
+          <p>
+            One day after:{" "}
+            {stringToDate.decode(withArgsResult.oneDayAfter).toLocaleString()}
+          </p>
+        )}
+      </section>
+    </div>
+  );
+}

From 5dc03c62a0bed5cd4007252d6781c5522f191126 Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 11:29:05 -0800
Subject: [PATCH 02/13] Add test in test.ts

---
 .../convex-helpers/server/zod4.functions.test.ts  | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/packages/convex-helpers/server/zod4.functions.test.ts b/packages/convex-helpers/server/zod4.functions.test.ts
index 163197a9..4096ead6 100644
--- a/packages/convex-helpers/server/zod4.functions.test.ts
+++ b/packages/convex-helpers/server/zod4.functions.test.ts
@@ -68,6 +68,14 @@ export const testQuery = zQuery({
   }),
 });
 
+export const testQueryNoArgs = zQuery({
+  args: {},
+  handler: async (_ctx, args) => {
+    assertType<{}>(args);
+  },
+  returns: z.null(),
+});
+
 /**
  * Test zCustomMutation with Zod schemas for args and return value
  */
@@ -227,6 +235,7 @@ export const generateUserId = mutation({
 const testApi: ApiFromModules<{
   fns: {
     testQuery: typeof testQuery;
+    testQueryNoArgs: typeof testQueryNoArgs;
     testMutation: typeof testMutation;
     testAction: typeof testAction;
     transform: typeof transform;
@@ -258,6 +267,12 @@ describe("zCustomQuery, zCustomMutation, zCustomAction", () => {
       >();
     });
 
+    test("zCustomQuery with no args", async () => {
+      const t = convexTest(schema, modules);
+      const response = await t.query(testApi.testQueryNoArgs);
+      expect(response).toBeNull();
+    });
+
     test("zCustomMutation", async () => {
       const t = convexTest(schema, modules);
       const response = await t.mutation(testApi.testMutation, {

From 13ffa8a5c6791611408026b185aae3a3d8b6e4bb Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 11:29:09 -0800
Subject: [PATCH 03/13] Fix types

---
 packages/convex-helpers/server/zod4.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/convex-helpers/server/zod4.ts b/packages/convex-helpers/server/zod4.ts
index 0bf128a3..908d5898 100644
--- a/packages/convex-helpers/server/zod4.ts
+++ b/packages/convex-helpers/server/zod4.ts
@@ -961,7 +961,7 @@ type ArgsInput<ArgsValidator extends ZodFields | zCore.$ZodObject<any> | void> =
   [ArgsValidator] extends [zCore.$ZodObject<any>]
     ? [zCore.input<ArgsValidator>]
     : [ArgsValidator] extends [ZodFields]
-      ? [zCore.input<zCore.$ZodObject<ArgsValidator>>]
+      ? [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
       : OneArgArray;
 
 // The args after they've been validated: passed to the handler

From 3a953e29a88cab1ae709b31ee68d97f70c56798c Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 11:42:01 -0800
Subject: [PATCH 04/13] Use strictObject everywhere

---
 packages/convex-helpers/server/zod4.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/convex-helpers/server/zod4.ts b/packages/convex-helpers/server/zod4.ts
index 908d5898..ec426ea3 100644
--- a/packages/convex-helpers/server/zod4.ts
+++ b/packages/convex-helpers/server/zod4.ts
@@ -846,7 +846,7 @@ function customFnBuilder(
 
     const returns =
       maybeObject && !(maybeObject instanceof zCore.$ZodType)
-        ? z.object(maybeObject)
+        ? z.strictObject(maybeObject)
         : maybeObject;
 
     const returnValidator =
@@ -877,7 +877,7 @@ function customFnBuilder(
             extra,
           );
           const rawArgs = pick(allArgs, Object.keys(argsValidator));
-          const parsed = z.object(argsValidator).safeParse(rawArgs);
+          const parsed = z.strictObject(argsValidator).safeParse(rawArgs);
           if (!parsed.success) {
             throw new ConvexError({
               ZodError: JSON.parse(

From 8c45beb5980198cc8607bfbe623350e40c125a05 Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 11:42:29 -0800
Subject: [PATCH 05/13] Fix empty types

---
 packages/convex-helpers/server/zod4.ts | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/convex-helpers/server/zod4.ts b/packages/convex-helpers/server/zod4.ts
index ec426ea3..d44437cc 100644
--- a/packages/convex-helpers/server/zod4.ts
+++ b/packages/convex-helpers/server/zod4.ts
@@ -961,7 +961,9 @@ type ArgsInput<ArgsValidator extends ZodFields | zCore.$ZodObject<any> | void> =
   [ArgsValidator] extends [zCore.$ZodObject<any>]
     ? [zCore.input<ArgsValidator>]
     : [ArgsValidator] extends [ZodFields]
-      ? [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
+      ? keyof ArgsValidator extends never
+        ? [{}]
+        : [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
       : OneArgArray;
 
 // The args after they've been validated: passed to the handler
@@ -970,7 +972,9 @@ type ArgsOutput<
 > = [ArgsValidator] extends [zCore.$ZodObject<any>]
   ? [zCore.output<ArgsValidator>]
   : [ArgsValidator] extends [ZodFields]
-    ? [zCore.output<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
+    ? keyof ArgsValidator extends never
+      ? [{}]
+      : [zCore.output<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
     : OneArgArray;
 
 type Overwrite<T, U> = Omit<T, keyof U> & U;

From 4413829575f7fa04281767467f662fa64d3c739c Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 14:39:20 -0800
Subject: [PATCH 06/13] Fix empty args

Co-authored-by: Ian Macartney <ian@convex.dev>
---
 convex/zodFunctionsExample.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/convex/zodFunctionsExample.ts b/convex/zodFunctionsExample.ts
index 479693d2..959cb37c 100644
--- a/convex/zodFunctionsExample.ts
+++ b/convex/zodFunctionsExample.ts
@@ -7,7 +7,7 @@ export const zQuery = zCustomQuery(query, NoOp);
 
 export const noArgs = zQuery({
   args: {},
-  handler: async (ctx) => {
+  handler: async (_ctx) => {
     return "Hello world!";
   },
 });

From c76ca213e2b22e4437e0672403da7da354325b27 Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 15:14:12 -0800
Subject: [PATCH 07/13] Fix tests

---
 .../server/zod4.functions.test.ts             | 21 +++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/packages/convex-helpers/server/zod4.functions.test.ts b/packages/convex-helpers/server/zod4.functions.test.ts
index 4096ead6..b8d860b8 100644
--- a/packages/convex-helpers/server/zod4.functions.test.ts
+++ b/packages/convex-helpers/server/zod4.functions.test.ts
@@ -71,9 +71,8 @@ export const testQuery = zQuery({
 export const testQueryNoArgs = zQuery({
   args: {},
   handler: async (_ctx, args) => {
-    assertType<{}>(args);
+    assertType<Record<string, never>>(args);
   },
-  returns: z.null(),
 });
 
 /**
@@ -267,10 +266,20 @@ describe("zCustomQuery, zCustomMutation, zCustomAction", () => {
       >();
     });
 
-    test("zCustomQuery with no args", async () => {
-      const t = convexTest(schema, modules);
-      const response = await t.query(testApi.testQueryNoArgs);
-      expect(response).toBeNull();
+    describe("zCustomQuery with no args", () => {
+      test("through t.query", async () => {
+        const t = convexTest(schema, modules);
+        const response = await t.query(testApi.testQueryNoArgs);
+        expect(response).toBeNull();
+      });
+
+      test("through t.run", async () => {
+        const t = convexTest(schema, modules);
+        const response = await t.run((ctx) =>
+          ctx.runQuery(testApi.testQueryNoArgs),
+        );
+        expect(response).toBeNull();
+      });
     });
 
     test("zCustomMutation", async () => {

From 52566b7af58344d3f863b89f73a25b4c2c720c78 Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 15:31:20 -0800
Subject: [PATCH 08/13] Fix style

---
 packages/convex-helpers/server/zod4.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/convex-helpers/server/zod4.ts b/packages/convex-helpers/server/zod4.ts
index d44437cc..fac309b0 100644
--- a/packages/convex-helpers/server/zod4.ts
+++ b/packages/convex-helpers/server/zod4.ts
@@ -962,7 +962,7 @@ type ArgsInput<ArgsValidator extends ZodFields | zCore.$ZodObject<any> | void> =
     ? [zCore.input<ArgsValidator>]
     : [ArgsValidator] extends [ZodFields]
       ? keyof ArgsValidator extends never
-        ? [{}]
+        ? OneArgArray
         : [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
       : OneArgArray;
 
@@ -973,7 +973,7 @@ type ArgsOutput<
   ? [zCore.output<ArgsValidator>]
   : [ArgsValidator] extends [ZodFields]
     ? keyof ArgsValidator extends never
-      ? [{}]
+      ? OneArgArray
       : [zCore.output<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
     : OneArgArray;
 

From f4da61e885f36cbf1d1a6e5e865af74a567b7dc1 Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 20:51:16 -0800
Subject: [PATCH 09/13] Revert "Fix style"

This reverts commit 52566b7af58344d3f863b89f73a25b4c2c720c78.
---
 packages/convex-helpers/server/zod4.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/convex-helpers/server/zod4.ts b/packages/convex-helpers/server/zod4.ts
index fac309b0..d44437cc 100644
--- a/packages/convex-helpers/server/zod4.ts
+++ b/packages/convex-helpers/server/zod4.ts
@@ -962,7 +962,7 @@ type ArgsInput<ArgsValidator extends ZodFields | zCore.$ZodObject<any> | void> =
     ? [zCore.input<ArgsValidator>]
     : [ArgsValidator] extends [ZodFields]
       ? keyof ArgsValidator extends never
-        ? OneArgArray
+        ? [{}]
         : [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
       : OneArgArray;
 
@@ -973,7 +973,7 @@ type ArgsOutput<
   ? [zCore.output<ArgsValidator>]
   : [ArgsValidator] extends [ZodFields]
     ? keyof ArgsValidator extends never
-      ? OneArgArray
+      ? [{}]
       : [zCore.output<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
     : OneArgArray;
 

From 23a8f3e5cbbc4264c4973f4e78edc7591be28a5c Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Thu, 20 Nov 2025 21:08:16 -0800
Subject: [PATCH 10/13] Remove ineffective fix

---
 packages/convex-helpers/server/zod4.ts | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/packages/convex-helpers/server/zod4.ts b/packages/convex-helpers/server/zod4.ts
index d44437cc..ec426ea3 100644
--- a/packages/convex-helpers/server/zod4.ts
+++ b/packages/convex-helpers/server/zod4.ts
@@ -961,9 +961,7 @@ type ArgsInput<ArgsValidator extends ZodFields | zCore.$ZodObject<any> | void> =
   [ArgsValidator] extends [zCore.$ZodObject<any>]
     ? [zCore.input<ArgsValidator>]
     : [ArgsValidator] extends [ZodFields]
-      ? keyof ArgsValidator extends never
-        ? [{}]
-        : [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
+      ? [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
       : OneArgArray;
 
 // The args after they've been validated: passed to the handler
@@ -972,9 +970,7 @@ type ArgsOutput<
 > = [ArgsValidator] extends [zCore.$ZodObject<any>]
   ? [zCore.output<ArgsValidator>]
   : [ArgsValidator] extends [ZodFields]
-    ? keyof ArgsValidator extends never
-      ? [{}]
-      : [zCore.output<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
+    ? [zCore.output<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
     : OneArgArray;
 
 type Overwrite<T, U> = Omit<T, keyof U> & U;

From b8d31a7f7bc3562a040d4be01b574a2222d448c3 Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Mon, 24 Nov 2025 14:10:29 -0800
Subject: [PATCH 11/13] Revert incorrect solution

---
 packages/convex-helpers/server/zod4.ts | 63 ++++++++++++++------------
 1 file changed, 35 insertions(+), 28 deletions(-)

diff --git a/packages/convex-helpers/server/zod4.ts b/packages/convex-helpers/server/zod4.ts
index ec426ea3..4a5f3c4b 100644
--- a/packages/convex-helpers/server/zod4.ts
+++ b/packages/convex-helpers/server/zod4.ts
@@ -430,15 +430,18 @@ export function zodToConvex<Z extends zCore.$ZodType>(
     }
     visited.add(validator);
 
-    if (validator instanceof zCore.$ZodDefault) {
-      return v.optional(zodToConvexInner(validator._zod.def.innerType));
-    }
-
-    if (validator instanceof zCore.$ZodPipe) {
-      return zodToConvexInner(validator._zod.def.in);
-    }
-
-    return zodToConvexCommon(validator, zodToConvexInner);
+    const result =
+      validator instanceof zCore.$ZodDefault
+        ? v.optional(zodToConvexInner(validator._zod.def.innerType))
+        : validator instanceof zCore.$ZodPipe
+          ? zodToConvexInner(validator._zod.def.in)
+          : zodToConvexCommon(validator, zodToConvexInner);
+
+    // After returning, we remove the validator from the visited set because
+    // we only want to detect circular types, not cases where part of a type
+    // is reused (e.g. `v.object({ field1: mySchema, field2: mySchema })`).
+    visited.delete(validator);
+    return result;
   }
 
   // `as any` because ConvexValidatorFromZod is defined from the behavior of zodToConvex.
@@ -517,20 +520,20 @@ export function zodOutputToConvex<Z extends zCore.$ZodType>(
     }
     visited.add(validator);
 
-    if (validator instanceof zCore.$ZodDefault) {
-      // Output: always there
-      return zodOutputToConvexInner(validator._zod.def.innerType);
-    }
-
-    if (validator instanceof zCore.$ZodPipe) {
-      return zodOutputToConvexInner(validator._zod.def.out);
-    }
-
-    if (validator instanceof zCore.$ZodTransform) {
-      return v.any();
-    }
-
-    return zodToConvexCommon(validator, zodOutputToConvexInner);
+    const result =
+      validator instanceof zCore.$ZodDefault
+        ? zodOutputToConvexInner(validator._zod.def.innerType)
+        : validator instanceof zCore.$ZodPipe
+          ? zodOutputToConvexInner(validator._zod.def.out)
+          : validator instanceof zCore.$ZodTransform
+            ? v.any()
+            : zodToConvexCommon(validator, zodOutputToConvexInner);
+
+    // After returning, we remove the validator from the visited set because
+    // we only want to detect circular types, not cases where part of a type
+    // is reused (e.g. `v.object({ field1: mySchema, field2: mySchema })`).
+    visited.delete(validator);
+    return result;
   }
 
   // `as any` because ConvexValidatorFromZodOutput is defined from the behavior of zodOutputToConvex.
@@ -846,7 +849,7 @@ function customFnBuilder(
 
     const returns =
       maybeObject && !(maybeObject instanceof zCore.$ZodType)
-        ? z.strictObject(maybeObject)
+        ? z.object(maybeObject)
         : maybeObject;
 
     const returnValidator =
@@ -877,7 +880,7 @@ function customFnBuilder(
             extra,
           );
           const rawArgs = pick(allArgs, Object.keys(argsValidator));
-          const parsed = z.strictObject(argsValidator).safeParse(rawArgs);
+          const parsed = await z.object(argsValidator).safeParseAsync(rawArgs);
           if (!parsed.success) {
             throw new ConvexError({
               ZodError: JSON.parse(
@@ -891,7 +894,9 @@ function customFnBuilder(
           const ret = await handler(finalCtx, finalArgs);
           // We don't catch the error here. It's a developer error and we
           // don't want to risk exposing the unexpected value to the client.
-          const result = returns ? returns.parse(ret) : ret;
+          const result = returns
+            ? await returns.parseAsync(ret === undefined ? null : ret)
+            : ret;
           if (added.onSuccess) {
             await added.onSuccess({ ctx, args, result });
           }
@@ -914,7 +919,9 @@ function customFnBuilder(
         const ret = await handler(finalCtx, finalArgs);
         // We don't catch the error here. It's a developer error and we
         // don't want to risk exposing the unexpected value to the client.
-        const result = returns ? returns.parse(ret) : ret;
+        const result = returns
+          ? await returns.parseAsync(ret === undefined ? null : ret)
+          : ret;
         if (added.onSuccess) {
           await added.onSuccess({ ctx, args, result });
         }
@@ -961,7 +968,7 @@ type ArgsInput<ArgsValidator extends ZodFields | zCore.$ZodObject<any> | void> =
   [ArgsValidator] extends [zCore.$ZodObject<any>]
     ? [zCore.input<ArgsValidator>]
     : [ArgsValidator] extends [ZodFields]
-      ? [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
+      ? [zCore.input<zCore.$ZodObject<ArgsValidator>>]
       : OneArgArray;
 
 // The args after they've been validated: passed to the handler

From 6c9a5f7e5c872844cfb0b6be0192532591a4bb53 Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Mon, 24 Nov 2025 16:02:37 -0800
Subject: [PATCH 12/13] Apply fix

---
 packages/convex-helpers/server/zod4.ts | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/packages/convex-helpers/server/zod4.ts b/packages/convex-helpers/server/zod4.ts
index 4a5f3c4b..6062e12a 100644
--- a/packages/convex-helpers/server/zod4.ts
+++ b/packages/convex-helpers/server/zod4.ts
@@ -960,15 +960,17 @@ type ReturnValueOutput<
 > = [ReturnsValidator] extends [zCore.$ZodType]
   ? Returns<zCore.output<ReturnsValidator>>
   : [ReturnsValidator] extends [ZodFields]
-    ? Returns<zCore.output<zCore.$ZodObject<ReturnsValidator>>>
+    ? Returns<zCore.output<zCore.$ZodObject<ReturnsValidator, zCore.$strict>>>
     : any;
 
 // The args before they've been validated: passed from the client
 type ArgsInput<ArgsValidator extends ZodFields | zCore.$ZodObject<any> | void> =
   [ArgsValidator] extends [zCore.$ZodObject<any>]
     ? [zCore.input<ArgsValidator>]
-    : [ArgsValidator] extends [ZodFields]
-      ? [zCore.input<zCore.$ZodObject<ArgsValidator>>]
+    : ArgsValidator extends Record<string, never>
+      ? [{}]
+      : [ArgsValidator] extends [Record<string, z.ZodTypeAny>]
+        ? [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
       : OneArgArray;
 
 // The args after they've been validated: passed to the handler

From 90490ae5f1cb55ae1a3b69bf954e99fe882195c5 Mon Sep 17 00:00:00 2001
From: Nicolas Ettlin <nicolas@convex.dev>
Date: Mon, 24 Nov 2025 17:46:13 -0800
Subject: [PATCH 13/13] Mute lint warning

---
 packages/convex-helpers/server/zod4.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/convex-helpers/server/zod4.ts b/packages/convex-helpers/server/zod4.ts
index 6062e12a..f0cd41c3 100644
--- a/packages/convex-helpers/server/zod4.ts
+++ b/packages/convex-helpers/server/zod4.ts
@@ -968,10 +968,11 @@ type ArgsInput<ArgsValidator extends ZodFields | zCore.$ZodObject<any> | void> =
   [ArgsValidator] extends [zCore.$ZodObject<any>]
     ? [zCore.input<ArgsValidator>]
     : ArgsValidator extends Record<string, never>
-      ? [{}]
+      ? // eslint-disable-next-line @typescript-eslint/no-empty-object-type
+        [{}]
       : [ArgsValidator] extends [Record<string, z.ZodTypeAny>]
         ? [zCore.input<zCore.$ZodObject<ArgsValidator, zCore.$strict>>]
-      : OneArgArray;
+        : OneArgArray;
 
 // The args after they've been validated: passed to the handler
 type ArgsOutput<