diff --git a/frontend/packages/swarm-ui/src/shell/Shell.tsx b/frontend/packages/swarm-ui/src/shell/Shell.tsx
index 19057f59..1f1b7746 100644
--- a/frontend/packages/swarm-ui/src/shell/Shell.tsx
+++ b/frontend/packages/swarm-ui/src/shell/Shell.tsx
@@ -35,6 +35,7 @@ import { SettingsMenu } from "@hive/shared/settings-menu.js";
 import { HideDebugSetting } from "@hive/shared/hide-debug-setting.js";
 import { useApplyThemeOverride } from "@hive/shared/theme-apply.js";
 import { useApplyMotionOverride } from "@hive/shared/motion-apply.js";
+import { isFullBleedRoute, isWideBodyRoute } from "./routes.js";
 import { useDynamicTabs } from "./useDynamicTabs.js";
 import { useSwarmName } from "./useSwarmName.js";
 import "./Shell.css";
@@ -58,38 +59,6 @@ const NAV_ITEMS: { href: string; label: string; accent: string }[] = [
   { href: "/components", label: "components", accent: "var(--blue)" },
 ];
 
-// Routes that opt out of `.shell-body`'s 60em readable-line-length cap
-// — mara screenshotted the issue report's 8-column table getting
-// clipped; that width is deliberate for the rest of the UI's cards/
-// forms, but too narrow for a wide table. `.shell-body-wide` (Shell.css) is a
-// modifier alongside the base class, not a replacement, so every other
-// route's layout is untouched. `/agents` joined for the same reason —
-// its own table view (plus the list+detail split) hits the same cap.
-const WIDE_BODY_ROUTES = new Set([
-  "/issues",
-  "/agents",
-  "/review-runs",
-  "/review-tryout",
-]);
-
-// `/agents/:name/terminal` (and a subagent's, under
-// `/agents/:name/subagents/:subagent/`) is full-bleed: the terminal fills
-// the whole viewport below the header bar, edge to edge (`shell-full` /
-// `shell-body-full` in Shell.css). It can't join the `Set` above — it's a
-// parameterized path, one literal string can't match every agent name.
-const FULL_BLEED_ROUTE_PATTERN =
-  /^\/agents\/[^/]+(\/subagents\/[^/]+)?\/terminal$/;
-
-// The start page (`/`) is full-bleed too: its rain backdrop fills the whole
-// body below the header.
-function isFullBleedRoute(location: string): boolean {
-  return location === "/" || FULL_BLEED_ROUTE_PATTERN.test(location);
-}
-
-function isWideBodyRoute(location: string): boolean {
-  return WIDE_BODY_ROUTES.has(location);
-}
-
 // Static fallback — matches `index.html`'s `<title>` default, so a page
 // never flashes something else before the fetch below resolves, and an
 // operator who never set `services.hyperhive.swarm.name` sees the exact
diff --git a/frontend/packages/swarm-ui/src/shell/routes.ts b/frontend/packages/swarm-ui/src/shell/routes.ts
new file mode 100644
index 00000000..e897e126
--- /dev/null
+++ b/frontend/packages/swarm-ui/src/shell/routes.ts
@@ -0,0 +1,35 @@
+// Which layout a route gets inside the shell: the readable-width cap, the
+// wide body, or full-bleed. Kept apart from `Shell.tsx` so it is plain
+// functions of a path, with no DOM or CSS behind it, and can be tested.
+
+// Routes that opt out of `.shell-body`'s 60em readable-line-length cap
+// — mara screenshotted the issue report's 8-column table getting
+// clipped; that width is deliberate for the rest of the UI's cards/
+// forms, but too narrow for a wide table. `.shell-body-wide` (Shell.css) is a
+// modifier alongside the base class, not a replacement, so every other
+// route's layout is untouched. `/agents` joined for the same reason —
+// its own table view (plus the list+detail split) hits the same cap.
+const WIDE_BODY_ROUTES = new Set([
+  "/issues",
+  "/agents",
+  "/review-runs",
+  "/review-tryout",
+]);
+
+// `/agents/:name/terminal` (and a subagent's, under
+// `/agents/:name/subagents/:subagent/`) is full-bleed: the terminal fills
+// the whole viewport below the header bar, edge to edge (`shell-full` /
+// `shell-body-full` in Shell.css). It can't join the `Set` above — it's a
+// parameterized path, one literal string can't match every agent name.
+const FULL_BLEED_ROUTE_PATTERN =
+  /^\/agents\/[^/]+(\/subagents\/[^/]+)?\/terminal$/;
+
+// The start page (`/`) is full-bleed too: its rain backdrop fills the whole
+// body below the header.
+export function isFullBleedRoute(location: string): boolean {
+  return location === "/" || FULL_BLEED_ROUTE_PATTERN.test(location);
+}
+
+export function isWideBodyRoute(location: string): boolean {
+  return WIDE_BODY_ROUTES.has(location);
+}
diff --git a/frontend/packages/swarm-ui/test/routes.test.mjs b/frontend/packages/swarm-ui/test/routes.test.mjs
new file mode 100644
index 00000000..ce10142c
--- /dev/null
+++ b/frontend/packages/swarm-ui/test/routes.test.mjs
@@ -0,0 +1,42 @@
+// The shell's per-route layout: which paths are full-bleed, which get the
+// wide body. Run by `npm test`.
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import { isFullBleedRoute, isWideBodyRoute } from "../src/shell/routes.ts";
+
+test("the start page is full-bleed", () => {
+  assert.equal(isFullBleedRoute("/"), true);
+});
+
+test("the hive directory moved off / and is not full-bleed", () => {
+  assert.equal(isFullBleedRoute("/hives"), false);
+  assert.equal(isWideBodyRoute("/hives"), false);
+});
+
+test("an agent's terminal and a subagent's are full-bleed", () => {
+  assert.equal(isFullBleedRoute("/agents/iris/terminal"), true);
+  assert.equal(
+    isFullBleedRoute("/agents/iris/subagents/scout-1/terminal"),
+    true,
+  );
+});
+
+test("the agents page and other routes are not full-bleed", () => {
+  for (const path of ["/agents", "/agents/iris", "/jobs", "/issues"]) {
+    assert.equal(isFullBleedRoute(path), false, path);
+  }
+});
+
+test("a terminal path with extra segments is not full-bleed", () => {
+  assert.equal(isFullBleedRoute("/agents/iris/terminal/extra"), false);
+  assert.equal(isFullBleedRoute("/agents//terminal"), false);
+});
+
+test("the wide-body routes are exactly the table pages", () => {
+  for (const path of ["/issues", "/agents", "/review-runs", "/review-tryout"]) {
+    assert.equal(isWideBodyRoute(path), true, path);
+  }
+  for (const path of ["/", "/jobs", "/schedules", "/components"]) {
+    assert.equal(isWideBodyRoute(path), false, path);
+  }
+});