diff --git a/src/browser/routes/agent.shared.test.ts b/src/browser/routes/agent.shared.test.ts
new file mode 100644
index 00000000000..4a43ba56891
--- /dev/null
+++ b/src/browser/routes/agent.shared.test.ts
@@ -0,0 +1,39 @@
+import { describe, expect, it } from "vitest";
+import { readBody, resolveTargetIdFromBody, resolveTargetIdFromQuery } from "./agent.shared.js";
+import type { BrowserRequest } from "./types.js";
+
+function requestWithBody(body: unknown): BrowserRequest {
+  return {
+    params: {},
+    query: {},
+    body,
+  };
+}
+
+describe("browser route shared helpers", () => {
+  describe("readBody", () => {
+    it("returns object bodies", () => {
+      expect(readBody(requestWithBody({ one: 1 }))).toEqual({ one: 1 });
+    });
+
+    it("normalizes non-object bodies to empty object", () => {
+      expect(readBody(requestWithBody(null))).toEqual({});
+      expect(readBody(requestWithBody("text"))).toEqual({});
+      expect(readBody(requestWithBody(["x"]))).toEqual({});
+    });
+  });
+
+  describe("target id parsing", () => {
+    it("extracts and trims targetId from body", () => {
+      expect(resolveTargetIdFromBody({ targetId: "  tab-1  " })).toBe("tab-1");
+      expect(resolveTargetIdFromBody({ targetId: "   " })).toBeUndefined();
+      expect(resolveTargetIdFromBody({ targetId: 123 })).toBeUndefined();
+    });
+
+    it("extracts and trims targetId from query", () => {
+      expect(resolveTargetIdFromQuery({ targetId: "  tab-2  " })).toBe("tab-2");
+      expect(resolveTargetIdFromQuery({ targetId: "" })).toBeUndefined();
+      expect(resolveTargetIdFromQuery({ targetId: false })).toBeUndefined();
+    });
+  });
+});
diff --git a/src/browser/routes/agent.storage.test.ts b/src/browser/routes/agent.storage.test.ts
new file mode 100644
index 00000000000..0990a160f4f
--- /dev/null
+++ b/src/browser/routes/agent.storage.test.ts
@@ -0,0 +1,40 @@
+import { describe, expect, it } from "vitest";
+import { parseStorageKind, parseStorageMutationRequest } from "./agent.storage.js";
+
+describe("browser storage route parsing", () => {
+  describe("parseStorageKind", () => {
+    it("accepts local and session", () => {
+      expect(parseStorageKind("local")).toBe("local");
+      expect(parseStorageKind("session")).toBe("session");
+    });
+
+    it("rejects unsupported values", () => {
+      expect(parseStorageKind("cookie")).toBeNull();
+      expect(parseStorageKind("")).toBeNull();
+    });
+  });
+
+  describe("parseStorageMutationRequest", () => {
+    it("returns parsed kind and trimmed target id", () => {
+      expect(
+        parseStorageMutationRequest("local", {
+          targetId: "  page-1  ",
+        }),
+      ).toEqual({
+        kind: "local",
+        targetId: "page-1",
+      });
+    });
+
+    it("returns null kind and undefined target id for invalid values", () => {
+      expect(
+        parseStorageMutationRequest("invalid", {
+          targetId: "   ",
+        }),
+      ).toEqual({
+        kind: null,
+        targetId: undefined,
+      });
+    });
+  });
+});