diff --git a/packages/convex-helpers/server/customFunctions.test.ts b/packages/convex-helpers/server/customFunctions.test.ts
index 7a5e615e..8b2af8f9 100644
--- a/packages/convex-helpers/server/customFunctions.test.ts
+++ b/packages/convex-helpers/server/customFunctions.test.ts
@@ -358,6 +358,34 @@ export const outerRemoves = outerRemover({
     return { ctxInner: ctx["inner"], ctxOuter: ctx["outer"], ...args };
   },
 });
+// Extend the previous ctx with new args
+export const outerExtender = customQuery(inner, {
+  args: { outer: v.string() },
+  input: async (ctx, args) => {
+    return { ctx: { outer: [args.outer, ctx.inner] }, args: {} };
+  },
+});
+export const outerExtends = outerExtender({
+  args: { a: v.string() },
+  handler: async (ctx, args) => {
+    return { outer: ctx.outer, inner: ctx.inner, ...args };
+  },
+});
+// Deleted ctx is correctly undefined on nested functions
+export const dbRemover = customQuery(
+  query,
+  customCtx(() => ({ db: undefined })),
+);
+export const outerDBRemover = customQuery(
+  dbRemover,
+  customCtx(() => ({ outer: "outer" })),
+);
+export const outerRemovesDB = outerDBRemover({
+  args: {},
+  handler: async (ctx, args) => {
+    return { db: ctx?.db ? "present" : "missing", outer: ctx.outer, ...args };
+  },
+});
 
 /**
  * Test helpers
@@ -388,6 +416,8 @@ const testApi: ApiFromModules<{
     create: typeof create;
     outerAdds: typeof outerAdds;
     outerRemoves: typeof outerRemoves;
+    outerExtends: typeof outerExtends;
+    outerRemovesDB: typeof outerRemovesDB;
   };
 }>["fns"] = anyApi["customFunctions.test"] as any;
 
@@ -568,4 +598,23 @@ describe("nested custom functions", () => {
       t.query(testApi.outerAdds, { a: 3 as any, outer: "" }),
     ).rejects.toThrow("Validator error: Expected `string`");
   });
+
+  test("extends prev ctx", async () => {
+    const t = convexTest(schema, modules);
+    expect(
+      await t.query(testApi.outerExtends, { a: "hi", outer: "extended" }),
+    ).toMatchObject({
+      inner: "inner",
+      outer: ["extended", "inner"],
+      a: "hi",
+    });
+  });
+
+  test("keeps deleted ctx", async () => {
+    const t = convexTest(schema, modules);
+    expect(await t.query(testApi.outerRemovesDB, {})).toMatchObject({
+      db: "missing",
+      outer: "outer",
+    });
+  });
 });