diff --git a/apps/portal/src/components/ui/stories.play.test.tsx b/apps/portal/src/components/ui/stories.play.test.tsx
index 6ed917da2..26a8c6695 100644
--- a/apps/portal/src/components/ui/stories.play.test.tsx
+++ b/apps/portal/src/components/ui/stories.play.test.tsx
@@ -24,11 +24,12 @@ import * as tabs from "./tabs.stories";
 import * as textarea from "./textarea.stories";
 import * as tooltip from "./tooltip.stories";
 import * as sonner from "./sonner.stories";
+import * as runsIterationFilter from "../../pages/RunsList.stories";
 
 const modules: Record<string, Record<string, unknown>> = {
   alert, alertDialog, checkbox, dialog, dropdownMenu, label, popover, scrollArea,
   select, separator, sheet, skeleton, switch: sw, table, tabs, textarea,
-  tooltip, sonner,
+  tooltip, sonner, runsIterationFilter,
 };
 
 afterEach(() => cleanup());
diff --git a/apps/portal/src/pages/RunsList.stories.tsx b/apps/portal/src/pages/RunsList.stories.tsx
new file mode 100644
index 000000000..a5195e784
--- /dev/null
+++ b/apps/portal/src/pages/RunsList.stories.tsx
@@ -0,0 +1,56 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+import { useState } from "react";
+import type { Meta, StoryObj } from "@storybook/react-vite";
+import { expect, screen, userEvent } from "storybook/test";
+import { NumericComparatorRow } from "./RunsList";
+
+function EmptyIterationFilter() {
+  const [op, setOp] = useState<"eq" | "gte" | "lte">("gte");
+  const [value, setValue] = useState("");
+
+  return (
+    <div className="w-72 space-y-2">
+      <NumericComparatorRow
+        label="Turns"
+        ariaLabel="Filter runs by number of turns"
+        op={op}
+        value={value}
+        onChange={(next) => {
+          setOp(next.op);
+          setValue(next.value);
+        }}
+      />
+      <output data-testid="iteration-filter">{`${op}:${value || "any"}`}</output>
+    </div>
+  );
+}
+
+const meta = {
+  title: "Pages/Runs/Iteration filter",
+  component: NumericComparatorRow,
+  tags: ["ai-generated", "needs-work"],
+} satisfies Meta<typeof NumericComparatorRow>;
+
+export default meta;
+type Story = StoryObj<typeof meta>;
+
+export const ChooseComparisonBeforeValue: Story = {
+  args: {
+    label: "Turns",
+    ariaLabel: "Filter runs by number of turns",
+    op: "gte",
+    value: "",
+    onChange: () => {},
+  },
+  render: () => <EmptyIterationFilter />,
+  play: async ({ canvas }) => {
+    await userEvent.click(canvas.getByRole("combobox", { name: "Filter runs by number of turns comparator" }));
+    await userEvent.click(await screen.findByRole("option", { name: "≤" }));
+    await expect(canvas.getByTestId("iteration-filter")).toHaveTextContent("lte:any");
+
+    await userEvent.type(canvas.getByRole("spinbutton", { name: "Filter runs by number of turns" }), "3");
+    await expect(canvas.getByTestId("iteration-filter")).toHaveTextContent("lte:3");
+  },
+};
diff --git a/apps/portal/src/pages/RunsList.tsx b/apps/portal/src/pages/RunsList.tsx
index 27b685df5..5567d86a4 100644
--- a/apps/portal/src/pages/RunsList.tsx
+++ b/apps/portal/src/pages/RunsList.tsx
@@ -383,7 +383,7 @@ function GroupByToggle({
 }
 
 // Sidebar filter widget: pick a comparator (≥ / ≤ / =) and a numeric value.
-// Clearing the input clears both the value and the op from the URL. Used for
+// The op is retained without a value so users can choose it before typing. Used for
 // the Turns and Max iterations filters; mirrors the API contract that accepts
 // `{turns, turnsOp}` / `{maxIterations, maxIterationsOp}` with op ∈ eq|gte|lte.
 const NUMERIC_OPS: ReadonlyArray<{ value: IterationOp; label: string; aria: string }> = [
@@ -392,7 +392,7 @@ const NUMERIC_OPS: ReadonlyArray<{ value: IterationOp; label: string; aria: stri
   { value: "eq", label: "=", aria: "equal to" },
 ];
 
-function NumericComparatorRow({
+export function NumericComparatorRow({
   label,
   ariaLabel,
   op,
@@ -1981,7 +1981,7 @@ export function RunsList() {
                 onChange={({ op, value }) => {
                   state.setFilters({
                     turns: value || null,
-                    turnsOp: value ? op : null,
+                    turnsOp: op,
                   });
                 }}
               />
@@ -1993,7 +1993,7 @@ export function RunsList() {
                 onChange={({ op, value }) => {
                   state.setFilters({
                     maxIter: value || null,
-                    maxIterOp: value ? op : null,
+                    maxIterOp: op,
                   });
                 }}
               />
diff --git a/docs/architecture/app-design.md b/docs/architecture/app-design.md
index f1a243262..a2444c00f 100644
--- a/docs/architecture/app-design.md
+++ b/docs/architecture/app-design.md
@@ -498,6 +498,10 @@ A single value compiles to an equality clause; multiple values compile to `$in`.
 | `criteria` | `scenario.criteria` |
 | `turns` / `maxIterations` | `run.turns` size / `maxIterations` |
 
+In the Portal's Iterations filter, the comparison operator can be selected
+before a number is entered. The operator is kept in URL state while the value is
+empty; the API query includes it only when the corresponding number is present.
+
 Additional cross-cutting filters:
 
 - **`(Unknown)` sentinel** — the literal value `__empty__` (exported as `EMPTY_FILTER_VALUE`)