diff --git a/clients/web/src/test/core/rootUnion.test.ts b/clients/web/src/test/core/rootUnion.test.ts
index 69100561..5a747ed5 100644
--- a/clients/web/src/test/core/rootUnion.test.ts
+++ b/clients/web/src/test/core/rootUnion.test.ts
@@ -901,6 +901,20 @@ describe("resolveRootUnion", () => {
       ).toBe(true);
     });
 
+    it("counts a required name a schema never declares", () => {
+      // Legal, and the tool plainly takes an argument — an App tool shaped this
+      // way must ask rather than being auto-invoked with `{}`.
+      expect(declaresAnyFields({ type: "object", required: ["token"] })).toBe(
+        true,
+      );
+      expect(
+        declaresAnyFields({
+          type: "object",
+          allOf: [{ type: "object", required: ["token"] }],
+        }),
+      ).toBe(true);
+    });
+
     it("reports none for a bare object schema", () => {
       expect(declaresAnyFields({ type: "object" })).toBe(false);
       expect(declaresAnyFields(undefined)).toBe(false);
diff --git a/clients/web/src/utils/toolUtils.test.ts b/clients/web/src/utils/toolUtils.test.ts
index 07c6446f..efe0211e 100644
--- a/clients/web/src/utils/toolUtils.test.ts
+++ b/clients/web/src/utils/toolUtils.test.ts
@@ -145,6 +145,12 @@ describe("hasInputFields with root composition (#2123)", () => {
     ).toBe(true);
   });
 
+  it("counts a required name the schema never declares", () => {
+    expect(hasInputFields(tool({ type: "object", required: ["token"] }))).toBe(
+      true,
+    );
+  });
+
   it("still reports no fields for a bare object schema", () => {
     expect(hasInputFields(tool({ type: "object" }))).toBe(false);
   });
diff --git a/core/json/rootUnion.ts b/core/json/rootUnion.ts
index b480f4e8..279cd1a7 100644
--- a/core/json/rootUnion.ts
+++ b/core/json/rootUnion.ts
@@ -498,6 +498,11 @@ export function declaresAnyFields(
 ): boolean {
   if (schema === undefined) return false;
   if (Object.keys(propertiesOf(schema)).length > 0) return true;
+  // A schema may require a name it never declares — `{ required: ["token"] }`
+  // is a legal object schema, and the tool plainly takes an argument. Counting
+  // it here is what stops an App tool with that shape being auto-invoked with
+  // `{}` for want of a `properties` map.
+  if (requiredOf(schema).length > 0) return true;
   // A `$ref`'s shape is unknown rather than empty, so it counts. Reporting "no
   // fields" for `anyOf: [{ $ref: … }, { $ref: … }]` would auto-invoke an App
   // tool with `{}` on the strength of something never read.