diff --git a/apps/web/src/composer.test.ts b/apps/web/src/composer.test.ts
index e6de2bf..8807e71 100644
--- a/apps/web/src/composer.test.ts
+++ b/apps/web/src/composer.test.ts
@@ -1,5 +1,9 @@
 import { describe, expect, it } from "vitest";
-import { DRAFT_LOCAL_SAVE_MS, DRAFT_REMOTE_CHECKPOINT_MS } from "./composer";
+import {
+  DRAFT_LOCAL_SAVE_MS,
+  DRAFT_REMOTE_CHECKPOINT_MS,
+  hasMeaningfulDraftContent,
+} from "./composer";
 
 describe("composer timing contract", () => {
   it("uses the documented local debounce and remote checkpoint interval", () => {
@@ -7,3 +11,36 @@ describe("composer timing contract", () => {
     expect(DRAFT_REMOTE_CHECKPOINT_MS).toBe(15_000);
   });
 });
+
+describe("composer content guard", () => {
+  const emptyDraft = {
+    recipients: [],
+    attachments: [],
+    subject: "",
+    bodyText: "",
+  };
+
+  it("does not treat whitespace-only draft fields as meaningful", () => {
+    expect(hasMeaningfulDraftContent(emptyDraft)).toBe(false);
+    expect(hasMeaningfulDraftContent({ ...emptyDraft, subject: "  ", bodyText: "\n" })).toBe(false);
+  });
+
+  it.each([
+    { ...emptyDraft, recipients: [{ role: "to" as const, address: "person@example.test" }] },
+    { ...emptyDraft, subject: "Subject" },
+    { ...emptyDraft, bodyText: "Message" },
+    {
+      ...emptyDraft,
+      attachments: [
+        {
+          objectId: "abcdef0123456789abcdef0123456789",
+          filename: "file.txt",
+          mediaType: "text/plain",
+          sizeBytes: 4,
+        },
+      ],
+    },
+  ])("recognizes meaningful draft content", (draft) => {
+    expect(hasMeaningfulDraftContent(draft)).toBe(true);
+  });
+});
diff --git a/apps/web/src/composer.tsx b/apps/web/src/composer.tsx
index dd8b529..15775e3 100644
--- a/apps/web/src/composer.tsx
+++ b/apps/web/src/composer.tsx
@@ -44,6 +44,17 @@ type EditorContent = { text: string; html: string };
 export const DRAFT_LOCAL_SAVE_MS = 2_000;
 export const DRAFT_REMOTE_CHECKPOINT_MS = 15_000;
 
+export function hasMeaningfulDraftContent(
+  draft: Pick<DraftContent, "attachments" | "bodyText" | "recipients" | "subject">,
+) {
+  return (
+    draft.recipients.length > 0 ||
+    draft.attachments.length > 0 ||
+    draft.subject.trim().length > 0 ||
+    draft.bodyText.trim().length > 0
+  );
+}
+
 function InitialContentPlugin({ text }: { text: string }) {
   const [editor] = useLexicalComposerContext();
   const initialized = useRef(false);
@@ -206,7 +217,13 @@ export function ComposePanel({
     }
   }, [accountId, content]);
 
+  const hasMeaningfulContent = useCallback(
+    () => hasMeaningfulDraftContent(content(latest.current.draft?.localRevision)),
+    [content],
+  );
+
   const checkpoint = useCallback(async () => {
+    if (!latest.current.draft && !hasMeaningfulContent()) return null;
     const saved =
       latest.current.dirty || !latest.current.draft ? await saveLocal() : latest.current.draft;
     if (!saved) throw new Error("draft_unavailable");
@@ -214,7 +231,7 @@ export function ComposePanel({
     setDraft(remote);
     setStatus("saved");
     return remote;
-  }, [accountId, saveLocal]);
+  }, [accountId, hasMeaningfulContent, saveLocal]);
 
   useEffect(() => {
     if (!editor || recovered.current || context.mode !== "new") return;
@@ -277,12 +294,13 @@ export function ComposePanel({
 
   // biome-ignore lint/correctness/useExhaustiveDependencies: content fields intentionally restart the two-second debounce.
   useEffect(() => {
+    if (!latest.current.draft && !hasMeaningfulContent()) return;
     const timer = window.setTimeout(
       () => void saveLocal().catch(() => undefined),
       DRAFT_LOCAL_SAVE_MS,
     );
     return () => window.clearTimeout(timer);
-  }, [to, cc, bcc, subject, editorContent, attachments, saveLocal]);
+  }, [to, cc, bcc, subject, editorContent, attachments, hasMeaningfulContent, saveLocal]);
 
   useEffect(() => {
     const interval = window.setInterval(
@@ -319,6 +337,10 @@ export function ComposePanel({
       setStatus("conflict");
       return;
     }
+    if (!latest.current.draft && !hasMeaningfulContent()) {
+      onClose();
+      return;
+    }
     try {
       await checkpoint();
       onClose();
diff --git a/apps/web/tests/inbox.spec.ts b/apps/web/tests/inbox.spec.ts
index 59aa7b5..cc2b4de 100644
--- a/apps/web/tests/inbox.spec.ts
+++ b/apps/web/tests/inbox.spec.ts
@@ -12,7 +12,7 @@ const account = {
 test("live inbox virtualizes large account-scoped pages and preserves selection", async ({
   page,
 }, testInfo) => {
-  testInfo.setTimeout(60_000);
+  testInfo.setTimeout(90_000);
   // Exercise the 100k acceptance target once; responsive projects use a
   // smaller page so the six-project suite does not duplicate a large fixture.
   const itemCount = testInfo.project.name === "desktop-large" ? 100_000 : 500;
@@ -509,6 +509,16 @@ test("live inbox virtualizes large account-scoped pages and preserves selection"
   await expect(page.getByText("No messages here")).toBeVisible();
 
   const composeButton = page.getByRole("button", { name: "Compose" });
+  if (!(await composeButton.isVisible())) {
+    await page.getByRole("button", { name: "Toggle navigation" }).click();
+  }
+  const draftsBeforeEmptyCompose = draftRequests.length;
+  await composeButton.click();
+  await page.waitForTimeout(2_100);
+  await page.getByRole("button", { name: "Close", exact: true }).click();
+  await expect(page.getByRole("region", { name: "New message" })).toHaveCount(0);
+  expect(draftRequests).toHaveLength(draftsBeforeEmptyCompose);
+
   if (!(await composeButton.isVisible())) {
     await page.getByRole("button", { name: "Toggle navigation" }).click();
   }