diff --git a/web/src/components/community/PublishModal.test.tsx b/web/src/components/community/PublishModal.test.tsx
index 1b413754e..63d37156a 100644
--- a/web/src/components/community/PublishModal.test.tsx
+++ b/web/src/components/community/PublishModal.test.tsx
@@ -6,6 +6,8 @@
 
 import { act, render, screen, waitFor } from "@testing-library/react";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { buildStoredPatternCode, communityPatternUrl } from "@/lib/community/license";
+import { CODE_MAX } from "@/lib/community/validate";
 import PublishModal from "./PublishModal";
 
 const push = vi.fn();
@@ -102,3 +104,90 @@ describe("PublishModal", () => {
     expect(server.mock).toHaveBeenCalledTimes(2);
   });
 });
+
+// The community stores a pattern inside its licence header and footer, and
+// "Open in Pattern Lab" hands that stored text to the lab unchanged. The API
+// takes the wrapping off before it measures; the modal measured the wrapped
+// text, so a fork it would have accepted was refused before it was sent.
+describe("PublishModal code size", () => {
+  /** A pattern body of exactly `length` characters. */
+  function bodyOf(length: number) {
+    const pad = "\n// ";
+    return `${CODE}${pad}${"x".repeat(length - CODE.length - pad.length)}`;
+  }
+
+  /** How a fork of `@ada`'s pattern comes back out of the community. */
+  function storedFork(body: string) {
+    return buildStoredPatternCode(body, {
+      title: "Pentagrid Tower (remix)",
+      license: "CC-BY-SA-4.0",
+      handle: "grace",
+      date: "2026-10-01",
+      basedOn: { title: "Pentagrid Tower", handle: "ada", url: communityPatternUrl("p0") },
+    });
+  }
+
+  function openFork(code: string) {
+    render(
+      <PublishModal
+        code={code}
+        parentId="p1"
+        parentTitle="Pentagrid Tower (remix)"
+        parentLicense="CC-BY-SA-4.0"
+        initialTitle="Pentagrid Tower (remix 2)"
+        onClose={() => {}}
+      />,
+    );
+    return screen.getByRole("button", { name: "Publish to the wall" });
+  }
+
+  it("publishes an untouched fork whose body fits under the cap", async () => {
+    const code = storedFork(bodyOf(99_700));
+    expect(code.length).toBeGreaterThan(CODE_MAX);
+
+    const button = openFork(code);
+    act(() => button.click());
+
+    expect(screen.queryByText(/KB of code/)).toBeNull();
+    expect(server.mock).toHaveBeenCalledTimes(1);
+    await server.answer(201, { id: "p2" });
+    await waitFor(() => expect(push).toHaveBeenCalledWith("/community/p/p2"));
+  });
+
+  it("saves the author's own post reopened in the lab, unedited", () => {
+    const code = storedFork(bodyOf(99_700));
+    render(
+      <PublishModal
+        code={code}
+        parentId={null}
+        parentTitle={null}
+        editOf={{
+          id: "p1",
+          title: "Pentagrid Tower (remix)",
+          description: null,
+          visibility: "public",
+          hasCpp: false,
+          portCount: 0,
+        }}
+        onClose={() => {}}
+      />,
+    );
+
+    act(() => screen.getByRole("button", { name: "Update this pattern" }).click());
+
+    expect(screen.queryByText(/KB of code/)).toBeNull();
+    expect(server.mock).toHaveBeenCalledTimes(1);
+    expect(server.mock.mock.calls[0]).toEqual([
+      "/api/community/patterns/p1",
+      expect.objectContaining({ method: "PATCH" }),
+    ]);
+  });
+
+  it("still stops a body over the cap before it is sent", () => {
+    const button = openFork(storedFork(bodyOf(CODE_MAX + 600)));
+    act(() => button.click());
+
+    expect(screen.getByText(/This pattern is 101 KB of code/)).toBeInTheDocument();
+    expect(server.mock).not.toHaveBeenCalled();
+  });
+});
diff --git a/web/src/components/community/PublishModal.tsx b/web/src/components/community/PublishModal.tsx
index 3e8adf055..3bdc40152 100644
--- a/web/src/components/community/PublishModal.tsx
+++ b/web/src/components/community/PublishModal.tsx
@@ -24,6 +24,7 @@ import {
   LICENSE_OPTIONS,
   forkLicenseOptions,
   licenseById,
+  stripShareWrapping,
 } from "@/lib/pattern/share";
 import { captureEvent } from "@/lib/posthogEvents";
 import AuthModal from "./AuthModal";
@@ -149,11 +150,16 @@ export default function PublishModal({
   const send = async (): Promise<boolean> => {
     const trimmed = title.trim();
     setError(null);
-    if (code.length > CODE_MAX) {
+    // Measured the way the API measures it, with the licence header and
+    // footer off. "Open in Pattern Lab" hands back the stored code with both
+    // still on, a few hundred characters the server never counts, and
+    // counting them here refused a pattern the server takes unchanged.
+    const codeLength = (code.length <= CODE_MAX * 2 ? stripShareWrapping(code) : code).length;
+    if (codeLength > CODE_MAX) {
       // The server says the same thing, but after a round trip that costs
       // one of five publishes a minute — and without the likely cause.
       setError(
-        `This pattern is ${Math.round(code.length / 1000)} KB of code; the community takes up to ${
+        `This pattern is ${Math.round(codeLength / 1000)} KB of code; the community takes up to ${
           CODE_MAX / 1000
         } KB. Imported images as pixel layers are the usual reason — hide or delete one and share again.`,
       );