diff --git a/src/webgpu/api/validation/render_pipeline/inter_stage.spec.ts b/src/webgpu/api/validation/render_pipeline/inter_stage.spec.ts
index 8290111eab93..4d11c557b2a8 100644
--- a/src/webgpu/api/validation/render_pipeline/inter_stage.spec.ts
+++ b/src/webgpu/api/validation/render_pipeline/inter_stage.spec.ts
@@ -315,23 +315,22 @@ g.test('max_variables_count,input')
     u.combine('isAsync', [false, true]).combineWithParams([
       // Number of user-defined output variables in test shader =
       //     device.limits.maxInterStageShaderVariables + numVariablesDelta
-      { numVariablesDelta: 0, useExtraBuiltinInputs: false },
-      { numVariablesDelta: 1, useExtraBuiltinInputs: false },
-      { numVariablesDelta: 0, useExtraBuiltinInputs: true },
-      { numVariablesDelta: -1, useExtraBuiltinInputs: true },
+      { numVariablesDelta: 0, useExtraBuiltinInputs: false, _success: true },
+      { numVariablesDelta: 1, useExtraBuiltinInputs: false, _success: false },
+      { numVariablesDelta: -1, useExtraBuiltinInputs: true, _success: true },
+      { numVariablesDelta: -2, useExtraBuiltinInputs: true, _success: false },
+      { numVariablesDelta: -3, useExtraBuiltinInputs: true, _success: true },
     ] as const)
   )
   .fn(t => {
-    const { isAsync, numVariablesDelta, useExtraBuiltinInputs } = t.params;
+    const { isAsync, numVariablesDelta, useExtraBuiltinInputs, _success: success } = t.params;
 
     const numVec4 = t.device.limits.maxInterStageShaderVariables + numVariablesDelta;
-    const numExtraVariables = useExtraBuiltinInputs ? 1 : 0;
-    const numUsedVariables = numVec4 + numExtraVariables;
-    const success = numUsedVariables <= t.device.limits.maxInterStageShaderVariables;
 
     const outputs = range(numVec4, i => `@location(${i}) vout${i}: vec4<f32>`);
     const inputs = range(numVec4, i => `@location(${i}) fin${i}: vec4<f32>`);
 
+    // NOTE: `numVec4` matches `inputs.length` here. We use this property later.
     if (useExtraBuiltinInputs) {
       inputs.push('@builtin(front_facing) front_facing_in: bool');
       if (!t.isCompatibility) {