diff --git a/packages/studio/src/hooks/useDomEditCommits.test.tsx b/packages/studio/src/hooks/useDomEditCommits.test.tsx
new file mode 100644
index 000000000..99e906973
--- /dev/null
+++ b/packages/studio/src/hooks/useDomEditCommits.test.tsx
@@ -0,0 +1,775 @@
+// @vitest-environment happy-dom
+import { act, createElement } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { MutableRefObject } from "react";
+import type { DomEditSelection, DomEditTextField } from "../components/editor/domEditing";
+import type { ImportedFontAsset } from "../components/editor/fontAssets";
+import { StudioSaveHttpError } from "../utils/studioSaveDiagnostics";
+import { trackStudioEvent } from "../utils/studioTelemetry";
+import { useDomEditCommits } from "./useDomEditCommits";
+
+Reflect.set(globalThis, "IS_REACT_ACT_ENVIRONMENT", true);
+
+vi.mock("../utils/studioTelemetry", () => ({
+  trackStudioEvent: vi.fn(),
+}));
+
+interface PatchResponseBody {
+  ok?: boolean;
+  changed?: boolean;
+  matched?: boolean;
+  content?: string;
+}
+
+interface RenderedDomEditCommits {
+  hook: ReturnType<typeof useDomEditCommits>;
+  showToast: ReturnType<typeof makeShowToast>;
+  recordEdit: ReturnType<typeof vi.fn<() => Promise<void>>>;
+  cleanup: () => void;
+}
+
+interface RenderDomEditCommitsOptions {
+  importedFontAssets?: ImportedFontAsset[];
+  writeProjectFile?: (path: string, content: string) => Promise<void>;
+}
+
+type FetchHandler = (
+  input: Parameters<typeof fetch>[0],
+  init?: Parameters<typeof fetch>[1],
+) => Promise<Response>;
+
+function makeShowToast() {
+  return vi.fn<(message: string, tone?: "error" | "info") => void>();
+}
+
+function ensureCssEscape(): void {
+  const escape = (value: string) => value.replace(/\\/g, "\\\\").replace(/"/g, '\\"');
+  if (typeof globalThis.CSS === "undefined") {
+    Object.defineProperty(globalThis, "CSS", {
+      value: { escape },
+      configurable: true,
+    });
+    return;
+  }
+  if (typeof globalThis.CSS.escape !== "function") {
+    Object.defineProperty(globalThis.CSS, "escape", {
+      value: escape,
+      configurable: true,
+    });
+  }
+}
+
+interface Deferred<T> {
+  promise: Promise<T>;
+  resolve: (value: T | PromiseLike<T>) => void;
+  reject: (reason?: unknown) => void;
+}
+
+function createDeferred<T>(): Deferred<T> {
+  let resolveFn: Deferred<T>["resolve"] | null = null;
+  let rejectFn: Deferred<T>["reject"] | null = null;
+  const promise = new Promise<T>((resolve, reject) => {
+    resolveFn = resolve;
+    rejectFn = reject;
+  });
+  if (!resolveFn || !rejectFn) throw new Error("Expected promise callbacks");
+  return { promise, resolve: resolveFn, reject: rejectFn };
+}
+
+function jsonResponse(body: unknown, status = 200): Response {
+  return new Response(JSON.stringify(body), {
+    status,
+    headers: { "content-type": "application/json" },
+  });
+}
+
+function requestUrl(input: Parameters<typeof fetch>[0]): string {
+  if (typeof input === "string") return input;
+  if (input instanceof URL) return input.toString();
+  return input.url;
+}
+
+function stubPatchFetch(
+  patchResponse: PatchResponseBody | Error,
+  sourceContent = '<div data-hf-id="hf-card" style="color: red">Card</div>',
+) {
+  const fetchMock = vi.fn(
+    async (
+      input: Parameters<typeof fetch>[0],
+      _init?: Parameters<typeof fetch>[1],
+    ): Promise<Response> => {
+      const url = requestUrl(input);
+      if (url.includes("/api/projects/p1/files/")) {
+        return jsonResponse({ content: sourceContent });
+      }
+      if (url.includes("/api/projects/p1/file-mutations/patch-element/")) {
+        if (patchResponse instanceof Error) throw patchResponse;
+        return jsonResponse(patchResponse);
+      }
+      throw new Error(`Unexpected fetch: ${url}`);
+    },
+  );
+  vi.stubGlobal("fetch", fetchMock);
+  return fetchMock;
+}
+
+function stubUnexpectedPersistFetch() {
+  const fetchMock = vi.fn(async (): Promise<Response> => {
+    throw new Error("persist should not run");
+  });
+  vi.stubGlobal("fetch", fetchMock);
+  return fetchMock;
+}
+
+async function flushAsyncWork(): Promise<void> {
+  for (let i = 0; i < 8; i += 1) {
+    await Promise.resolve();
+  }
+}
+
+function createPreviewElement(
+  bodyHtml = '<div data-hf-id="hf-card" style="color: red">Card</div>',
+): {
+  iframe: HTMLIFrameElement;
+  element: HTMLElement;
+} {
+  const iframe = document.createElement("iframe");
+  document.body.append(iframe);
+  const doc = iframe.contentDocument;
+  if (!doc) throw new Error("Expected iframe contentDocument");
+  doc.body.innerHTML = bodyHtml;
+  const element = doc.querySelector('[data-hf-id="hf-card"]');
+  if (!(element instanceof HTMLElement)) throw new Error("Expected HTML target element");
+  return { iframe, element };
+}
+
+function textField(input: {
+  key: string;
+  value: string;
+  source: DomEditTextField["source"];
+  tagName?: string;
+}): DomEditTextField {
+  return {
+    key: input.key,
+    label: input.key,
+    value: input.value,
+    tagName: input.tagName ?? "span",
+    attributes: [],
+    inlineStyles: {},
+    computedStyles: {},
+    source: input.source,
+  };
+}
+
+function createSelection(
+  element: HTMLElement,
+  overrides: Partial<DomEditSelection> = {},
+): DomEditSelection {
+  const base: DomEditSelection = {
+    element,
+    label: "Hero title",
+    tagName: "div",
+    sourceFile: "index.html",
+    compositionPath: "index.html",
+    isCompositionHost: false,
+    isInsideLockedComposition: false,
+    boundingBox: { x: 0, y: 0, width: 120, height: 40 },
+    textContent: element.textContent,
+    dataAttributes: {},
+    inlineStyles: { color: "red" },
+    computedStyles: {},
+    textFields: [],
+    capabilities: {
+      canSelect: true,
+      canEditStyles: true,
+      canMove: true,
+      canResize: true,
+      canApplyManualOffset: true,
+      canApplyManualSize: true,
+      canApplyManualRotation: true,
+    },
+    hfId: "hf-card",
+    selector: '[data-hf-id="hf-card"]',
+    selectorIndex: 0,
+  };
+  return { ...base, ...overrides };
+}
+
+function renderDomEditCommits(
+  selection: DomEditSelection,
+  iframe: HTMLIFrameElement,
+  options: RenderDomEditCommitsOptions = {},
+) {
+  const captured: { current: ReturnType<typeof useDomEditCommits> | null } = { current: null };
+  const showToast = makeShowToast();
+  const recordEdit = vi.fn(async () => {});
+  const previewIframeRef: MutableRefObject<HTMLIFrameElement | null> = { current: iframe };
+  const projectIdRef: MutableRefObject<string | null> = { current: "p1" };
+  const domEditSaveTimestampRef: MutableRefObject<number> = { current: 0 };
+
+  function Probe() {
+    captured.current = useDomEditCommits({
+      activeCompPath: "index.html",
+      previewIframeRef,
+      showToast,
+      queueDomEditSave: async (save) => save(),
+      writeProjectFile: options.writeProjectFile ?? (async () => {}),
+      domEditSaveTimestampRef,
+      editHistory: { recordEdit },
+      fileTree: [],
+      importedFontAssetsRef: { current: options.importedFontAssets ?? [] },
+      projectId: "p1",
+      projectIdRef,
+      reloadPreview: vi.fn(),
+      domEditSelection: selection,
+      applyDomSelection: vi.fn(),
+      clearDomSelection: vi.fn(),
+      refreshDomEditSelectionFromPreview: vi.fn(),
+      buildDomSelectionFromTarget: vi.fn(async () => null),
+    });
+    return null;
+  }
+
+  const container = document.createElement("div");
+  const root: Root = createRoot(container);
+  act(() => {
+    root.render(createElement(Probe));
+  });
+
+  if (!captured.current) throw new Error("Expected hook result");
+  return {
+    hook: captured.current,
+    showToast,
+    recordEdit,
+    cleanup: () => {
+      act(() => {
+        root.unmount();
+      });
+      container.remove();
+    },
+  } satisfies RenderedDomEditCommits;
+}
+
+async function commitStyleAgainst(response: Parameters<typeof stubPatchFetch>[0]) {
+  stubPatchFetch(response);
+  const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+  const { iframe, element } = createPreviewElement();
+  const rendered = renderDomEditCommits(createSelection(element), iframe);
+  await act(async () => {
+    await rendered.hook.handleDomStyleCommit("color", "blue");
+  });
+  return {
+    element,
+    rendered,
+    warnSpy,
+    cleanup: () => {
+      warnSpy.mockRestore();
+      rendered.cleanup();
+    },
+  };
+}
+
+function renderStyleCommitWithFetch(fetchHandler: FetchHandler) {
+  const fetchMock = vi.fn(fetchHandler);
+  vi.stubGlobal("fetch", fetchMock);
+  const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+  const { iframe, element } = createPreviewElement();
+  const rendered = renderDomEditCommits(createSelection(element), iframe);
+  return {
+    element,
+    fetchMock,
+    rendered,
+    warnSpy,
+    cleanup: () => {
+      warnSpy.mockRestore();
+      rendered.cleanup();
+    },
+  };
+}
+
+async function expectRejectedTextStructureEdit(
+  commit: (hook: ReturnType<typeof useDomEditCommits>) => Promise<unknown>,
+): Promise<void> {
+  const fetchMock = stubUnexpectedPersistFetch();
+  const { iframe, element } = createPreviewElement(
+    '<div data-hf-id="hf-card"><span>First</span><span>Second</span></div>',
+  );
+  const originalInnerHtml = element.innerHTML;
+  const selection = createSelection(element, {
+    textFields: [
+      textField({ key: "first", value: "First", source: "child" }),
+      textField({ key: "second", value: "Second", source: "child" }),
+    ],
+  });
+  const rendered = renderDomEditCommits(selection, iframe);
+
+  try {
+    await act(async () => {
+      await commit(rendered.hook);
+    });
+
+    expect(fetchMock).not.toHaveBeenCalled();
+    expect(rendered.showToast).toHaveBeenCalledWith(
+      expect.stringContaining("text structure change"),
+      "error",
+    );
+    expect(element.innerHTML).toBe(originalInnerHtml);
+    expect(rendered.recordEdit).not.toHaveBeenCalled();
+  } finally {
+    rendered.cleanup();
+  }
+}
+
+describe("useDomEditCommits style persist handling", () => {
+  beforeEach(() => {
+    ensureCssEscape();
+    vi.clearAllMocks();
+    vi.unstubAllGlobals();
+    document.body.replaceChildren();
+  });
+
+  it("toasts and reverts a style commit when the server cannot resolve the source element", async () => {
+    const { element, rendered, cleanup } = await commitStyleAgainst({
+      ok: true,
+      changed: false,
+      matched: false,
+    });
+
+    try {
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        expect.stringMatching(/Couldn't save "Hero title": Couldn't find this element/),
+        "error",
+      );
+      expect(element.style.getPropertyValue("color")).toBe("red");
+      expect(trackStudioEvent).toHaveBeenCalledWith(
+        "save_skipped_unresolvable",
+        expect.objectContaining({ target_source_file: "index.html" }),
+      );
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("warns without a toast when the server matched the element but reported no change", async () => {
+    const { rendered, warnSpy, cleanup } = await commitStyleAgainst({
+      ok: true,
+      changed: false,
+      matched: true,
+    });
+
+    try {
+      expect(rendered.showToast).not.toHaveBeenCalled();
+      expect(warnSpy).toHaveBeenCalledWith(
+        "[Studio] DOM edit persist no-op",
+        expect.objectContaining({ operations: "inline-style:color" }),
+      );
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("toasts and reverts a style commit when the patch request rejects", async () => {
+    const { element, rendered, cleanup } = await commitStyleAgainst(new Error("network down"));
+
+    try {
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        'Couldn\'t save "Hero title": network down',
+        "error",
+      );
+      expect(element.style.getPropertyValue("color")).toBe("red");
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("keeps the optimistic style and records history when the patch succeeds", async () => {
+    const { element, rendered, cleanup } = await commitStyleAgainst({
+      ok: true,
+      changed: true,
+      matched: true,
+      content: '<div data-hf-id="hf-card" style="color: blue">Card</div>',
+    });
+
+    try {
+      expect(rendered.showToast).not.toHaveBeenCalled();
+      expect(element.style.getPropertyValue("color")).toBe("blue");
+      expect(rendered.recordEdit).toHaveBeenCalledTimes(1);
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("keeps a newer style value when an older overlapping commit later fails", async () => {
+    const firstPatch = createDeferred<Response>();
+    const secondPatch = createDeferred<Response>();
+    let patchCount = 0;
+    const { element, rendered, cleanup } = renderStyleCommitWithFetch(async (input) => {
+      const url = requestUrl(input);
+      if (url.includes("/api/projects/p1/files/")) {
+        return jsonResponse({
+          content: '<div data-hf-id="hf-card" style="color: red">Card</div>',
+        });
+      }
+      if (url.includes("/api/projects/p1/file-mutations/patch-element/")) {
+        patchCount += 1;
+        return patchCount === 1 ? firstPatch.promise : secondPatch.promise;
+      }
+      throw new Error(`Unexpected fetch: ${url}`);
+    });
+
+    try {
+      const firstCommit = rendered.hook.handleDomStyleCommit("color", "blue");
+      await flushAsyncWork();
+      expect(patchCount).toBe(1);
+
+      const secondCommit = rendered.hook.handleDomStyleCommit("color", "green");
+      await flushAsyncWork();
+      expect(patchCount).toBe(2);
+
+      secondPatch.resolve(
+        jsonResponse({
+          ok: true,
+          changed: true,
+          matched: true,
+          content: '<div data-hf-id="hf-card" style="color: green">Card</div>',
+        }),
+      );
+      await secondCommit;
+      expect(element.style.getPropertyValue("color")).toBe("green");
+
+      firstPatch.reject(new Error("server rejected blue"));
+      await firstCommit;
+
+      expect(element.style.getPropertyValue("color")).toBe("green");
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("toasts read failures from the source file fetch", async () => {
+    const { rendered, cleanup } = renderStyleCommitWithFetch(async (input) => {
+      const url = requestUrl(input);
+      if (url.includes("/api/projects/p1/files/")) {
+        return new Response("read failed", { status: 503 });
+      }
+      throw new Error(`Unexpected fetch: ${url}`);
+    });
+
+    try {
+      await act(async () => {
+        await rendered.hook.handleDomStyleCommit("color", "blue");
+      });
+
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        expect.stringContaining("Failed to read index.html (503)"),
+        "error",
+      );
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("keeps the already-persisted patch and toasts once when the prepareContent write fails", async () => {
+    stubPatchFetch(
+      {
+        ok: true,
+        changed: true,
+        matched: true,
+        content:
+          '<!doctype html><html><head></head><body><div data-hf-id="hf-card">Card</div></body></html>',
+      },
+      '<!doctype html><html><head></head><body><div data-hf-id="hf-card">Card</div></body></html>',
+    );
+    const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+    const { iframe, element } = createPreviewElement();
+    const selection = createSelection(element, {
+      textFields: [textField({ key: "self", value: "Card", source: "self", tagName: "div" })],
+    });
+    const rendered = renderDomEditCommits(createSelection(element), iframe, {
+      writeProjectFile: async () => {
+        throw new StudioSaveHttpError("Failed to save index.html (500)", 500);
+      },
+    });
+
+    try {
+      await act(async () => {
+        await rendered.hook.commitDomTextFields(
+          selection,
+          [textField({ key: "self", value: "Card", source: "self", tagName: "div" })],
+          {
+            importedFont: {
+              family: "Imported",
+              path: "fonts/Imported.woff2",
+              url: "/api/projects/p1/preview/fonts/Imported.woff2",
+            },
+          },
+        );
+      });
+
+      // The base patch already landed server-side before the font-face write
+      // failed, so this is recorded as a completed edit (not reverted/re-toasted
+      // as a full failure) — only the font embellishment is reported as lost.
+      expect(rendered.showToast).toHaveBeenCalledTimes(1);
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        expect.stringContaining("Saved, but couldn't finish updating index.html"),
+        "error",
+      );
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        expect.stringContaining("Failed to save index.html (500)"),
+        "error",
+      );
+      expect(rendered.recordEdit).toHaveBeenCalledTimes(1);
+    } finally {
+      warnSpy.mockRestore();
+      rendered.cleanup();
+    }
+  });
+
+  it("keeps a rejected patch request (HTTP error) to one toast", async () => {
+    const { rendered, cleanup } = renderStyleCommitWithFetch(async (input) => {
+      const url = requestUrl(input);
+      if (url.includes("/api/projects/p1/files/")) {
+        return jsonResponse({
+          content: '<div data-hf-id="hf-card" style="color: red">Card</div>',
+        });
+      }
+      if (url.includes("/api/projects/p1/file-mutations/patch-element/")) {
+        return jsonResponse({ error: "invalid value", fields: ["style.color"] }, 400);
+      }
+      throw new Error(`Unexpected fetch: ${url}`);
+    });
+
+    try {
+      await act(async () => {
+        await rendered.hook.handleDomStyleCommit("color", "blue");
+      });
+
+      expect(rendered.showToast).toHaveBeenCalledTimes(1);
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        "Couldn't save edit: invalid value (style.color)",
+        "error",
+      );
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("keeps the unsafe-value path to one toast", async () => {
+    stubPatchFetch({
+      ok: true,
+      changed: true,
+      matched: true,
+      content: '<div data-hf-id="hf-card" style="color: blue">Card</div>',
+    });
+    const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+    const { iframe, element } = createPreviewElement();
+    const rendered = renderDomEditCommits(createSelection(element, { id: null }), iframe);
+
+    try {
+      await act(async () => {
+        await rendered.hook.handleDomStyleCommit("color", "blue");
+      });
+
+      expect(rendered.showToast).toHaveBeenCalledTimes(1);
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        "Couldn't save edit because it contains invalid layout values",
+        "error",
+      );
+    } finally {
+      warnSpy.mockRestore();
+      rendered.cleanup();
+    }
+  });
+
+  it("refuses added child text fields without persisting serialized markup", async () => {
+    await expectRejectedTextStructureEdit((hook) => hook.handleDomAddTextField("first"));
+  });
+
+  it("refuses removed child text fields without persisting serialized markup", async () => {
+    await expectRejectedTextStructureEdit((hook) => hook.handleDomRemoveTextField("first"));
+  });
+
+  it("keeps single self text commits on the text-content path", async () => {
+    stubPatchFetch({
+      ok: true,
+      changed: true,
+      matched: true,
+      content: '<div data-hf-id="hf-card">A &lt; B</div>',
+    });
+    const { iframe, element } = createPreviewElement('<div data-hf-id="hf-card">Card</div>');
+    const selection = createSelection(element, {
+      textFields: [textField({ key: "self", value: "Card", source: "self", tagName: "div" })],
+    });
+    const rendered = renderDomEditCommits(selection, iframe);
+
+    try {
+      await act(async () => {
+        await rendered.hook.handleDomTextCommit("A < B", "self");
+      });
+
+      expect(rendered.showToast).not.toHaveBeenCalled();
+      expect(rendered.recordEdit).toHaveBeenCalledTimes(1);
+      expect(element.textContent).toBe("A < B");
+    } finally {
+      rendered.cleanup();
+    }
+  });
+
+  it("reverts and toasts a text commit when the server rejects the patch", async () => {
+    stubPatchFetch(new Error("network down"));
+    const { iframe, element } = createPreviewElement('<div data-hf-id="hf-card">Card</div>');
+    const selection = createSelection(element, {
+      textFields: [textField({ key: "self", value: "Card", source: "self", tagName: "div" })],
+    });
+    const rendered = renderDomEditCommits(selection, iframe);
+
+    try {
+      await act(async () => {
+        await rendered.hook.handleDomTextCommit("Updated", "self");
+      });
+
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        'Couldn\'t save "Hero title": network down',
+        "error",
+      );
+      expect(element.textContent).toBe("Card");
+      expect(rendered.recordEdit).not.toHaveBeenCalled();
+    } finally {
+      rendered.cleanup();
+    }
+  });
+});
+
+describe("useDomEditCommits attribute persist handling", () => {
+  beforeEach(() => {
+    ensureCssEscape();
+    vi.clearAllMocks();
+    vi.unstubAllGlobals();
+    document.body.replaceChildren();
+  });
+
+  it("toasts and reverts a data-attribute commit when the server cannot resolve the source element", async () => {
+    stubPatchFetch({ ok: true, changed: false, matched: false });
+    const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+    const { iframe, element } = createPreviewElement();
+    const rendered = renderDomEditCommits(createSelection(element), iframe);
+
+    try {
+      await act(async () => {
+        await rendered.hook.handleDomAttributeCommit("volume", "0.8");
+      });
+
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        expect.stringMatching(/Couldn't save "Hero title": Couldn't find this element/),
+        "error",
+      );
+      expect(element.getAttribute("data-volume")).toBeNull();
+    } finally {
+      warnSpy.mockRestore();
+      rendered.cleanup();
+    }
+  });
+
+  it("toasts and reverts a data-attribute commit when the patch request rejects", async () => {
+    stubPatchFetch(new Error("network down"));
+    const { iframe, element } = createPreviewElement();
+    element.setAttribute("data-volume", "0.5");
+    const rendered = renderDomEditCommits(createSelection(element), iframe);
+
+    try {
+      await act(async () => {
+        await rendered.hook.handleDomAttributeCommit("volume", "0.8");
+      });
+
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        'Couldn\'t save "Hero title": network down',
+        "error",
+      );
+      expect(element.getAttribute("data-volume")).toBe("0.5");
+    } finally {
+      rendered.cleanup();
+    }
+  });
+
+  it("keeps a data-attribute commit on success", async () => {
+    stubPatchFetch({
+      ok: true,
+      changed: true,
+      matched: true,
+      content: '<div data-hf-id="hf-card" data-volume="0.8">Card</div>',
+    });
+    const { iframe, element } = createPreviewElement();
+    const rendered = renderDomEditCommits(createSelection(element), iframe);
+
+    try {
+      await act(async () => {
+        await rendered.hook.handleDomAttributeCommit("volume", "0.8");
+      });
+
+      expect(rendered.showToast).not.toHaveBeenCalled();
+      expect(element.getAttribute("data-volume")).toBe("0.8");
+    } finally {
+      rendered.cleanup();
+    }
+  });
+
+  it("toasts and reverts an html-attribute commit when the patch request rejects", async () => {
+    stubPatchFetch(new Error("network down"));
+    const { iframe, element } = createPreviewElement();
+    const rendered = renderDomEditCommits(createSelection(element), iframe);
+
+    try {
+      await act(async () => {
+        await rendered.hook.handleDomHtmlAttributeCommit("muted", "true");
+      });
+
+      expect(rendered.showToast).toHaveBeenCalledWith(
+        'Couldn\'t save "Hero title": network down',
+        "error",
+      );
+      expect(element.getAttribute("muted")).toBeNull();
+    } finally {
+      rendered.cleanup();
+    }
+  });
+
+  it("keeps a newer html-attribute value when an older overlapping commit later fails", async () => {
+    const first = createDeferred<Response>();
+    let call = 0;
+    const { iframe, element } = createPreviewElement();
+    const rendered = renderDomEditCommits(createSelection(element), iframe);
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async (input: Parameters<typeof fetch>[0]) => {
+        const url = requestUrl(input);
+        if (url.includes("/api/projects/p1/files/")) {
+          return jsonResponse({ content: '<div data-hf-id="hf-card"></div>' });
+        }
+        call += 1;
+        if (call === 1) return first.promise;
+        return jsonResponse({ ok: true, changed: true, matched: true, content: "" });
+      }),
+    );
+
+    try {
+      // Older commit's persist stays pending (captures previousValue=null); the
+      // newer commit captures previousValue="first-value" (the older commit's
+      // optimistic apply) and succeeds before the older one rejects. Without the
+      // per-key version guard, the stale rejection would revert to the older
+      // commit's own previousValue (null) and stomp the newer commit's value.
+      const firstCommit = act(async () => {
+        await rendered.hook.handleDomHtmlAttributeCommit("muted", "first-value");
+      });
+      await act(async () => {
+        await rendered.hook.handleDomHtmlAttributeCommit("muted", "second-value");
+      });
+      first.reject(new Error("stale request failed"));
+      await firstCommit;
+
+      expect(element.getAttribute("muted")).toBe("second-value");
+    } finally {
+      rendered.cleanup();
+    }
+  });
+});