diff --git a/CHANGELOG.md b/CHANGELOG.md
index 848f26d..e263b0d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,12 @@
 
 All notable changes to Codex Extras are documented in this file.
 
+## Unreleased
+
+- Add an optional, version-checked developer repair for repeated onboarding in
+  OpenAI Codex 26.1007.21434, with backup, rollback and regression tests. The
+  repair is excluded from the Extras VSIX and never runs automatically.
+
 ## 1.1.0
 
 - Add a Codex Chats Activity Bar panel with local chat history, automatic
diff --git a/README.md b/README.md
index b5c5777..ea0d506 100644
--- a/README.md
+++ b/README.md
@@ -81,3 +81,11 @@ Codex Extras is an independent, unofficial open-source project. It is not affili
 ## License
 
 [MIT](LICENSE)
+
+## Local onboarding troubleshooting
+
+If the official Codex welcome screen repeatedly appears after completion, see
+[the optional local onboarding repair](docs/local-onboarding-fix.md) for OpenAI
+extension version `26.1007.21434`. This developer script changes the installed
+OpenAI extension only when explicitly run, keeps backups, and supports rollback.
+It is excluded from the Extras VSIX and does not run automatically.
diff --git a/docs/local-onboarding-fix.md b/docs/local-onboarding-fix.md
new file mode 100644
index 0000000..08025b3
--- /dev/null
+++ b/docs/local-onboarding-fix.md
@@ -0,0 +1,61 @@
+# Local OpenAI Codex onboarding repair
+
+This is a development repair of `openai.chatgpt` version `26.1007.21434`.
+It is not part of the Codex Extras runtime or VSIX. Do not publish this as an
+Extras feature: the defective onboarding decision belongs to OpenAI's webview.
+
+The installed extension's `FGi()` checks `isLoading` before reading the saved
+completion flag. Failed and paused requests can have `isLoading: false` without
+successful data, so they incorrectly select onboarding. The repair requires
+`isSuccess` instead. It also makes an already open onboarding page navigate home
+when the saved completion flag becomes available and says onboarding is complete.
+A failed read remains on the loading screen until a successful refetch; this
+repair does not diagnose or repair the underlying request failure.
+
+Local inspection confirmed both saved completion flags were true. Isolated tests
+reproduce the incorrect decision in the original installed code. The particular
+request failure triggering the user's repeated welcome screen is not yet proven.
+After applying the repair and reloading VS Code, the reporter confirmed that the repeated welcome screen stopped appearing. The exact triggering request failure remains unverified.
+
+## Apply
+
+From the repository root, pass the absolute installed extension directory:
+
+```powershell
+node scripts/local-onboarding-fix.cjs "$env:USERPROFILE/.vscode/extensions/openai.chatgpt-26.1007.21434-win32-x64"
+```
+
+Both target files are validated before writes. Original files are saved alongside
+them with `.codex-extras-nux-backup` appended. The script rejects unsupported
+versions and unexpected code. Reapplying the repair is safe.
+
+Wait until all local Codex tasks in the window have finished before running
+**Developer: Reload Window** from the VS Code command palette. Reload restarts
+the official Codex extension and can interrupt its running tasks. Then open a
+new agent through both the Extras toolbar and the Codex Chats plus button,
+including while another empty agent is open. Repeat after another window reload,
+again waiting for active tasks to finish first.
+The welcome screen should not return and existing conversations should still open.
+
+An OpenAI extension update may replace these files. Do not automatically reapply
+the repair to another version; inspect and test its code first.
+
+## Restore
+
+```powershell
+node scripts/local-onboarding-fix.cjs "$env:USERPROFILE/.vscode/extensions/openai.chatgpt-26.1007.21434-win32-x64" --restore
+```
+
+Reload the VS Code window again after active tasks have finished.
+Restore refuses to overwrite files that changed
+after the repair.
+
+## Tests
+
+```powershell
+node --test test/local-onboarding-fix.test.cjs
+npm.cmd test
+```
+
+The focused tests cover the original regression, legitimate first use, completion,
+an already open welcome page, version validation, backup, idempotence and restore.
diff --git a/scripts/local-onboarding-fix.cjs b/scripts/local-onboarding-fix.cjs
new file mode 100644
index 0000000..da00063
--- /dev/null
+++ b/scripts/local-onboarding-fix.cjs
@@ -0,0 +1,63 @@
+"use strict";
+
+// Local repair for OpenAI's extension, NOT part of the Codex Extras runtime.
+const fs = require("node:fs");
+const path = require("node:path");
+const crypto = require("node:crypto");
+
+const version = "26.1007.21434";
+const guardBefore = "function FGi(){let{data:e,isLoading:t}=UC(hs.NUX_2025_09_15),{authMethod:n}=Lf();if(!t)return e||n==null?`none`:n===`chatgptAuthTokens`||n===`chatgpt`?`2025-09-15-full-chatgpt-auth`:`2025-09-15-apikey-auth`}";
+const guardAfter = guardBefore.replace("isLoading:t", "isSuccess:t").replace("if(!t)", "if(t)");
+const pageBefore = "let s=h(),l;e[0]!==s||e[1]!==n||e[2]!==t?";
+const pageAfter = "let s=h(),l;X.useEffect(()=>{if(n===`none`)s(`/`)},[n,s]);e[0]!==s||e[1]!==n||e[2]!==t?";
+const patches = [
+  { file: "app-initial-c014f9ee4429.js", before: guardBefore, after: guardAfter },
+  { file: "first-run-afdf3f60ec3c.js", before: pageBefore, after: pageAfter },
+];
+
+function transform(source, before, after) {
+  if (source.includes(after) && !source.includes(before)) return source;
+  if (source.split(before).length !== 2 || source.includes(after)) {
+    throw new Error("Unrecognized extension code; refusing to patch");
+  }
+  return source.replace(before, after);
+}
+
+function apply(extensionDirectory, restore = false) {
+  const manifest = JSON.parse(fs.readFileSync(path.join(extensionDirectory, "package.json"), "utf8"));
+  if (manifest.publisher !== "openai" || manifest.name !== "chatgpt" || manifest.version !== version) {
+    throw new Error(`Repair supports only openai.chatgpt ${version}`);
+  }
+  // Validate BOTH files before writing either one. Never overwrite a backup.
+  const changes = patches.map(({ file, before, after }) => {
+    const target = path.join(extensionDirectory, "webview", "assets", file);
+    const backup = `${target}.codex-extras-nux-backup`;
+    const original = fs.readFileSync(target, "utf8");
+    const repaired = transform(original, before, after);
+    if (restore) {
+      const saved = fs.readFileSync(backup, "utf8");
+      if (transform(saved, before, after) !== original) throw new Error("File changed since repair; refusing restore");
+      return { target, content: saved };
+    }
+    if (fs.existsSync(backup)) {
+      if (transform(fs.readFileSync(backup, "utf8"), before, after) !== repaired) {
+        throw new Error("Backup does not match installed extension");
+      }
+    } else if (original !== repaired) {
+      return { target, backup, original, content: repaired };
+    }
+    return { target, content: repaired };
+  });
+  for (const change of changes) {
+    if (change.backup) fs.writeFileSync(change.backup, change.original, { flag: "wx" });
+    fs.writeFileSync(change.target, change.content);
+    console.log(`${restore ? "Restored" : "Patched"} ${path.basename(change.target)} sha256=${crypto.createHash("sha256").update(change.content).digest("hex")}`);
+  }
+}
+
+if (require.main === module) {
+  if (!process.argv[2]) throw new Error("Usage: node scripts/local-onboarding-fix.cjs EXTENSION_DIRECTORY [--restore]");
+  apply(path.resolve(process.argv[2]), process.argv.includes("--restore"));
+}
+
+module.exports = { apply, transform, patches, guardBefore, guardAfter, pageAfter, version };
diff --git a/test/local-onboarding-fix.test.cjs b/test/local-onboarding-fix.test.cjs
new file mode 100644
index 0000000..cec3f8b
--- /dev/null
+++ b/test/local-onboarding-fix.test.cjs
@@ -0,0 +1,60 @@
+"use strict";
+const assert = require("node:assert/strict");
+const test = require("node:test");
+const vm = require("node:vm");
+const fs = require("node:fs");
+const os = require("node:os");
+const path = require("node:path");
+const { apply, transform, patches, guardBefore, guardAfter, pageAfter, version } = require("../scripts/local-onboarding-fix.cjs");
+
+function decide(source, query, authMethod = "chatgpt") {
+  return vm.runInNewContext(`${source}; FGi()`, {
+    UC: () => query, hs: { NUX_2025_09_15: "completed" }, Lf: () => ({ authMethod }),
+  });
+}
+
+test("regression: a paused or failed read must never reopen onboarding", () => {
+  for (const query of [
+    { data: undefined, isLoading: false, isSuccess: false, isPending: true, fetchStatus: "paused" },
+    { data: undefined, isLoading: false, isSuccess: false, isError: true },
+  ]) {
+    assert.equal(decide(guardBefore, query), "2025-09-15-full-chatgpt-auth");
+    assert.equal(decide(guardAfter, query), undefined);
+  }
+});
+
+test("successful reads preserve genuine first use and completed onboarding", () => {
+  assert.equal(decide(guardAfter, { data: true, isSuccess: true }), "none");
+  assert.equal(decide(guardAfter, { data: false, isSuccess: true }), "2025-09-15-full-chatgpt-auth");
+  assert.equal(decide(guardAfter, { data: false, isSuccess: true }, "apikey"), "2025-09-15-apikey-auth");
+  assert.equal(decide(guardAfter, { data: false, isSuccess: true }, null), "none");
+  assert.equal(decide(guardAfter, { data: undefined, isSuccess: false, isLoading: true }), undefined);
+});
+
+test("an already open welcome page exits after a successful completion read", () => {
+  const effect = pageAfter.slice(pageAfter.indexOf("X.useEffect"), pageAfter.indexOf(";e[0]"));
+  for (const state of [undefined, "2025-09-15-full-chatgpt-auth", "none"]) {
+    const routes = [];
+    vm.runInNewContext(effect, { X: { useEffect: (fn) => fn() }, n: state, s: (route) => routes.push(route) });
+    assert.deepEqual(routes, state === "none" ? ["/"] : []);
+  }
+});
+
+test("local deployment is version checked, idempotent, backed up and reversible", (t) => {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), "codex-nux-fix-"));
+  t.after(() => fs.rmSync(dir, { recursive: true, force: true }));
+  fs.mkdirSync(path.join(dir, "webview", "assets"), { recursive: true });
+  fs.writeFileSync(path.join(dir, "package.json"), JSON.stringify({ publisher: "openai", name: "chatgpt", version }));
+  for (const patch of patches) fs.writeFileSync(path.join(dir, "webview", "assets", patch.file), patch.before);
+  apply(dir);
+  apply(dir);
+  for (const patch of patches) assert.equal(fs.readFileSync(path.join(dir, "webview", "assets", patch.file), "utf8"), patch.after);
+  apply(dir, true);
+  for (const patch of patches) assert.equal(fs.readFileSync(path.join(dir, "webview", "assets", patch.file), "utf8"), patch.before);
+  fs.writeFileSync(path.join(dir, "webview", "assets", patches[1].file), "unexpected build");
+  assert.throws(() => apply(dir), /Unrecognized/);
+  assert.equal(fs.readFileSync(path.join(dir, "webview", "assets", patches[0].file), "utf8"), patches[0].before);
+  assert.throws(() => transform("unknown", patches[0].before, patches[0].after), /Unrecognized/);
+  fs.writeFileSync(path.join(dir, "package.json"), JSON.stringify({ publisher: "openai", name: "chatgpt", version: "other" }));
+  assert.throws(() => apply(dir), /supports only/);
+});