diff --git a/.changeset/22911-blank-prefixed-project-name.md b/.changeset/22911-blank-prefixed-project-name.md
new file mode 100644
index 00000000000..4199774d73b
--- /dev/null
+++ b/.changeset/22911-blank-prefixed-project-name.md
@@ -0,0 +1,14 @@
+---
+"create-objectstack": patch
+---
+
+fix(create-objectstack): a project name that starts with the template's namespace scaffolds instead of being refused
+
+Clause-②: no
+
+A project whose namespace begins with the template's own namespace plus `_` (for example `blank-probe`, namespace `blank_probe`, under the `blank` template) was refused with exit 1: "1 object name(s) still carry the template's 'blank_' prefix … This is a bug in the scaffolder". The rewrite was correct (`blank_note` became `blank_probe_note`), but the check that verifies it tested each name against the template prefix alone, and `blank_probe_note` starts with `blank_`.
+
+- The check now reports a name as stale only when it carries the template's prefix and not the new namespace's prefix, so `blank-probe` scaffolds with objects named `blank_probe_*`.
+- A name the rewrite really missed (`blank_note` under namespace `blank_probe`) is still refused, as before.
+- The same rule applies to every template namespace; no name is treated specially.
+- No migration: a project that scaffolded before this release is unaffected, and a name that was refused before can be scaffolded again.
diff --git a/packages/create-objectstack/src/index.ts b/packages/create-objectstack/src/index.ts
index b68538942c9..7677081f619 100644
--- a/packages/create-objectstack/src/index.ts
+++ b/packages/create-objectstack/src/index.ts
@@ -242,7 +242,7 @@ function rewriteProjectIdentity(
   if (templateNamespace && namespace !== templateNamespace) {
     const srcDir = path.join(targetDir, 'src');
     rewriteObjectNamePrefix(srcDir, templateNamespace, namespace);
-    const stale = findStaleNamespacePrefixes(srcDir, templateNamespace);
+    const stale = findStaleNamespacePrefixes(srcDir, templateNamespace, namespace);
     if (stale.length > 0) {
       const shown = stale
         .slice(0, 5)
diff --git a/packages/create-objectstack/src/rewrite-identity.test.ts b/packages/create-objectstack/src/rewrite-identity.test.ts
index 3b42075ca24..a272c6cb864 100644
--- a/packages/create-objectstack/src/rewrite-identity.test.ts
+++ b/packages/create-objectstack/src/rewrite-identity.test.ts
@@ -117,14 +117,14 @@ describe('findStaleNamespacePrefixes', () => {
   it('reports nothing once the rewrite has run', () => {
     writeObject('todo_task.object.ts', 'todo_task');
     rewriteObjectNamePrefix(path.join(dir, 'src'), 'todo', 'my_app');
-    expect(findStaleNamespacePrefixes(path.join(dir, 'src'), 'todo')).toEqual([]);
+    expect(findStaleNamespacePrefixes(path.join(dir, 'src'), 'todo', 'my_app')).toEqual([]);
   });
 
   it('reports what a skipped rewrite leaves behind — the #4902 failure state', () => {
     writeObject('todo_task.object.ts', 'todo_task');
     writeObject('todo_label.object.ts', 'todo_label');
     // No rewrite at all: exactly what the old manifest-only guard produced.
-    const stale = findStaleNamespacePrefixes(path.join(dir, 'src'), 'todo');
+    const stale = findStaleNamespacePrefixes(path.join(dir, 'src'), 'todo', 'my_app');
     expect(stale).toHaveLength(2);
     expect(stale.map((s) => s.file).sort()).toEqual([
       path.join('objects', 'todo_label.object.ts'),
@@ -132,6 +132,40 @@ describe('findStaleNamespacePrefixes', () => {
     ]);
     expect(stale[0].line).toBeGreaterThan(0);
   });
+
+  // A new namespace that itself begins with the template namespace plus `_`
+  // (project `blank-probe` → namespace `blank_probe`): every CORRECT rewrite
+  // then carries the old prefix as well. The predicate is one rule for every
+  // template namespace, so the same pins run against more than one.
+  describe.each([
+    ['blank', 'blank_probe'],
+    ['todo', 'todo_list'],
+  ])('when the new namespace extends the template namespace (%s → %s)', (oldNs, newNs) => {
+    it('reports nothing once the rewrite has run', () => {
+      writeObject('note.object.ts', `${oldNs}_note`);
+      expect(rewriteObjectNamePrefix(path.join(dir, 'src'), oldNs, newNs)).toBe(1);
+      expect(
+        fs.readFileSync(path.join(dir, 'src', 'objects', 'note.object.ts'), 'utf8'),
+      ).toContain(`name: '${newNs}_note'`);
+      expect(findStaleNamespacePrefixes(path.join(dir, 'src'), oldNs, newNs)).toEqual([]);
+    });
+
+    it('CONTROL: still reports a genuinely stale name', () => {
+      writeObject('note.object.ts', `${oldNs}_note`);
+      // No rewrite: `<old>_note` is not under `<new>_`, so the project is rejected.
+      const stale = findStaleNamespacePrefixes(path.join(dir, 'src'), oldNs, newNs);
+      expect(stale).toHaveLength(1);
+      expect(stale[0].text).toContain(`'${oldNs}_note'`);
+    });
+
+    it('judges each literal, so a correct name does not hide a stale one on its line', () => {
+      fs.writeFileSync(
+        path.join(dir, 'src', 'objects', 'pair.object.ts'),
+        `export const o = [{ name: '${newNs}_ok' }, { name: '${oldNs}_note' }];\n`,
+      );
+      expect(findStaleNamespacePrefixes(path.join(dir, 'src'), oldNs, newNs)).toHaveLength(1);
+    });
+  });
 });
 
 // ── deriveManifestId — the pin the scaffold's id is held against ─────────────
diff --git a/packages/create-objectstack/src/rewrite-identity.ts b/packages/create-objectstack/src/rewrite-identity.ts
index 0b0a7185e92..35eae3f4e75 100644
--- a/packages/create-objectstack/src/rewrite-identity.ts
+++ b/packages/create-objectstack/src/rewrite-identity.ts
@@ -159,20 +159,33 @@ export function rewriteObjectNamePrefix(
 }
 
 /**
- * Any `name: '<oldNs>_…'` literal still present after a rewrite — i.e. metadata
- * the scaffolded project will be rejected for. Each entry is `file:line`
- * relative to `dir`, plus the offending text.
+ * Any `name: '<oldNs>_…'` literal still present after a rewrite that does NOT
+ * also carry the `<newNs>_` prefix — i.e. metadata the scaffolded project will
+ * be rejected for. Each entry is `file:line` relative to `dir`, plus the
+ * offending text.
+ *
+ * Both halves of the predicate are needed. A new namespace may itself begin
+ * with `<oldNs>_` (project `blank-probe` → namespace `blank_probe` under the
+ * `blank` template), and then every CORRECTLY rewritten name (`blank_probe_note`)
+ * carries the old prefix too; testing the old prefix alone reports the rewrite
+ * as stale and refuses a valid project. A name under `<newNs>_` satisfies the
+ * `${namespace}_${shortName}` rule whatever else it starts with, so it is
+ * never stale. One predicate for every template namespace — no name is special.
+ * Judged per literal, so a correct name cannot hide a stale one on its line.
  */
 export function findStaleNamespacePrefixes(
   dir: string,
   oldNs: string,
+  newNs: string,
 ): { file: string; line: number; text: string }[] {
-  const re = namePrefixRe(oldNs, '');
+  const oldRe = namePrefixRe(oldNs, 'g');
+  const newRe = namePrefixRe(newNs, '');
   const stale: { file: string; line: number; text: string }[] = [];
   for (const file of tsFiles(dir)) {
     const lines = fs.readFileSync(file, 'utf8').split('\n');
     for (let i = 0; i < lines.length; i++) {
-      if (re.test(lines[i])) {
+      const literals = [...lines[i].matchAll(oldRe)].map((m) => m[0]);
+      if (literals.some((literal) => !newRe.test(literal))) {
         stale.push({
           file: path.relative(dir, file),
           line: i + 1,
diff --git a/packages/create-objectstack/src/scaffold-namespace-extends-template.test.ts b/packages/create-objectstack/src/scaffold-namespace-extends-template.test.ts
new file mode 100644
index 00000000000..f87f0443400
--- /dev/null
+++ b/packages/create-objectstack/src/scaffold-namespace-extends-template.test.ts
@@ -0,0 +1,84 @@
+// Copyright (c) 2026 ObjectStack contributors. Apache-2.0 license.
+//
+// A project whose namespace BEGINS with the template's own namespace plus `_`
+// (`blank-probe` → `blank_probe` under the `blank` template) must scaffold.
+// The scaffolder's stale-prefix self-check once tested each rewritten object
+// name against the template prefix alone; `blank_probe_note` carries `blank_`,
+// so a correct rewrite was refused with "This is a bug in the scaffolder".
+//
+// Drives the real CLI end to end via `tsx` — index.ts calls `program.parse()`
+// on import, so `rewriteProjectIdentity` cannot be called directly (the same
+// constraint and pattern as scaffold-description.test.ts). One case per
+// bundled template, each probe named after THAT template's own namespace, so a
+// second template is covered the day it is registered.
+
+import { describe, it, expect, afterEach } from 'vitest';
+import { spawnSync } from 'node:child_process';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { validateObjectNamespacePrefix } from '@objectstack/spec/kernel';
+import { TEMPLATES } from './template-registry.js';
+import { readTemplateNamespace } from './rewrite-identity.js';
+
+const HERE = path.dirname(fileURLToPath(import.meta.url));
+const PKG_ROOT = path.resolve(HERE, '..');
+const REPO_ROOT = path.resolve(PKG_ROOT, '..', '..');
+const TSX = path.join(REPO_ROOT, 'node_modules', '.bin', 'tsx');
+const INDEX_TS = path.join(PKG_ROOT, 'src', 'index.ts');
+
+/** Every `name: '…'` literal in the `*.ts` files under `dir`. */
+function nameLiterals(dir: string): string[] {
+  const names: string[] = [];
+  for (const rel of fs.readdirSync(dir, { recursive: true, encoding: 'utf8' })) {
+    if (!rel.endsWith('.ts')) continue;
+    const text = fs.readFileSync(path.join(dir, rel), 'utf8');
+    for (const m of text.matchAll(/\bname:\s*(['"`])([a-z0-9_]+)\1/g)) names.push(m[2]);
+  }
+  return names.sort();
+}
+
+let tmp: string | undefined;
+afterEach(() => {
+  if (tmp) fs.rmSync(tmp, { recursive: true, force: true });
+  tmp = undefined;
+});
+
+describe('a project namespace that extends the template namespace', () => {
+  it.each(
+    Object.entries(TEMPLATES).map(([template, info]) => {
+      const ns = readTemplateNamespace(path.join(HERE, 'templates', info.source.dir));
+      if (!ns) throw new Error(`bundled template '${template}' declares no namespace`);
+      return [template, ns, `${ns.replace(/_/g, '-')}-probe`, info.source.dir] as const;
+    }),
+  )('%s (namespace %s): `%s` scaffolds, every object moved under the new namespace', (template, ns, project, dir) => {
+    const templateNames = nameLiterals(path.join(HERE, 'templates', dir, 'src')).filter(
+      (n) => n.startsWith(`${ns}_`),
+    );
+    // Precondition: the template really ships prefixed names, or nothing is pinned.
+    expect(templateNames.length).toBeGreaterThan(0);
+
+    tmp = fs.mkdtempSync(path.join(os.tmpdir(), 'create-objectstack-ns-extends-'));
+    const run = spawnSync(
+      TSX,
+      [INDEX_TS, project, '--template', template, '--skip-install', '--skip-skills'],
+      { cwd: tmp, encoding: 'utf8' },
+    );
+    expect(run.status, `${run.stdout}\n${run.stderr}`).toBe(0);
+
+    const projectDir = path.join(tmp, project);
+    const newNs = `${ns}_probe`;
+    expect(readTemplateNamespace(projectDir)).toBe(newNs);
+
+    const scaffolded = nameLiterals(path.join(projectDir, 'src')).filter((n) =>
+      n.startsWith(`${ns}_`),
+    );
+    expect(scaffolded).toEqual(
+      templateNames.map((n) => `${newNs}_${n.slice(ns.length + 1)}`).sort(),
+    );
+    for (const name of scaffolded) {
+      expect(validateObjectNamespacePrefix(name, newNs), name).toBeNull();
+    }
+  }, 30_000);
+});