diff --git a/src/resources/extensions/gsd/tests/import-done-milestones.test.ts b/src/resources/extensions/gsd/tests/import-done-milestones.test.ts
new file mode 100644
index 000000000..6ec953714
--- /dev/null
+++ b/src/resources/extensions/gsd/tests/import-done-milestones.test.ts
@@ -0,0 +1,42 @@
+/**
+ * Regression test for #3699 — import milestones with all-done slices as complete
+ *
+ * During DB migration, milestones whose roadmap slices are all marked done
+ * should be imported with status "complete" instead of "active".
+ */
+
+import { describe, test } from 'node:test';
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { dirname, join } from 'node:path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const importerSrc = readFileSync(
+  join(__dirname, '..', 'md-importer.ts'),
+  'utf-8',
+);
+
+describe('import done milestones as complete (#3699)', () => {
+  test('all-slices-done check sets milestoneStatus to complete', () => {
+    // The importer should check if all roadmap slices are done
+    assert.match(importerSrc, /roadmap\.slices\.every\(s\s*=>\s*s\.done\)/,
+      'should check roadmap.slices.every(s => s.done)');
+  });
+
+  test('milestoneStatus is set to complete when all slices done', () => {
+    // Find the all-done guard and verify it sets 'complete'
+    const everyIdx = importerSrc.indexOf('roadmap.slices.every(s => s.done)');
+    assert.ok(everyIdx > -1, 'all-slices-done check should exist');
+    const afterCheck = importerSrc.slice(everyIdx, everyIdx + 200);
+    assert.match(afterCheck, /milestoneStatus\s*=\s*'complete'/,
+      'should set milestoneStatus to complete when all slices are done');
+  });
+
+  test('roadmap.slices.length > 0 guard prevents false positives', () => {
+    assert.match(importerSrc, /roadmap\.slices\.length\s*>\s*0/,
+      'should guard against empty slices array');
+  });
+});