diff --git a/src/resources/extensions/gsd/bootstrap/dynamic-tools.ts b/src/resources/extensions/gsd/bootstrap/dynamic-tools.ts
index 3dab4b47a..da502ce67 100644
--- a/src/resources/extensions/gsd/bootstrap/dynamic-tools.ts
+++ b/src/resources/extensions/gsd/bootstrap/dynamic-tools.ts
@@ -10,10 +10,37 @@ export async function ensureDbOpen(): Promise<boolean> {
   try {
     const db = await import("../gsd-db.js");
     if (db.isDbAvailable()) return true;
-    const dbPath = join(process.cwd(), ".gsd", "gsd.db");
+
+    const basePath = process.cwd();
+    const gsdDir = join(basePath, ".gsd");
+    const dbPath = join(gsdDir, "gsd.db");
+
+    // Open existing DB file
     if (existsSync(dbPath)) {
       return db.openDatabase(dbPath);
     }
+
+    // No DB file — create + migrate from Markdown if .gsd/ has content
+    if (existsSync(gsdDir)) {
+      const hasDecisions = existsSync(join(gsdDir, "DECISIONS.md"));
+      const hasRequirements = existsSync(join(gsdDir, "REQUIREMENTS.md"));
+      const hasMilestones = existsSync(join(gsdDir, "milestones"));
+      if (hasDecisions || hasRequirements || hasMilestones) {
+        const opened = db.openDatabase(dbPath);
+        if (opened) {
+          try {
+            const { migrateFromMarkdown } = await import("../md-importer.js");
+            migrateFromMarkdown(basePath);
+          } catch (err) {
+            process.stderr.write(
+              `gsd-db: ensureDbOpen auto-migration failed: ${(err as Error).message}\n`,
+            );
+          }
+        }
+        return opened;
+      }
+    }
+
     return false;
   } catch {
     return false;
diff --git a/src/resources/extensions/gsd/tests/ensure-db-open.test.ts b/src/resources/extensions/gsd/tests/ensure-db-open.test.ts
new file mode 100644
index 000000000..48c5703d5
--- /dev/null
+++ b/src/resources/extensions/gsd/tests/ensure-db-open.test.ts
@@ -0,0 +1,168 @@
+// ensureDbOpen — Tests that the lazy DB opener creates + migrates the database
+// when .gsd/ exists with Markdown content but no gsd.db file.
+//
+// This covers the bug where interactive (non-auto) sessions got
+// "GSD database is not available" because ensureDbOpen only opened
+// existing DB files but never created them.
+
+import { createTestContext } from './test-helpers.ts';
+import * as path from 'node:path';
+import * as os from 'node:os';
+import * as fs from 'node:fs';
+import { closeDatabase, isDbAvailable, getDecisionById } from '../gsd-db.ts';
+
+const { assertEq, assertTrue, report } = createTestContext();
+
+function makeTmpDir(): string {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-ensure-db-'));
+  return dir;
+}
+
+function cleanupDir(dir: string): void {
+  try {
+    fs.rmSync(dir, { recursive: true, force: true });
+  } catch { /* swallow */ }
+}
+
+// ═══════════════════════════════════════════════════════════════════════════
+// ensureDbOpen creates DB + migrates when .gsd/ has Markdown
+// ═══════════════════════════════════════════════════════════════════════════
+
+console.log('\n── ensureDbOpen: creates DB from Markdown ──');
+
+{
+  const tmpDir = makeTmpDir();
+  const gsdDir = path.join(tmpDir, '.gsd');
+  fs.mkdirSync(gsdDir, { recursive: true });
+
+  // Write a minimal DECISIONS.md so migration has content
+  const decisionsContent = `# Decisions
+
+| # | When | Scope | Decision | Choice | Rationale | Revisable |
+|---|------|-------|----------|--------|-----------|-----------|
+| D001 | M001 | architecture | Use SQLite | SQLite | Sync API | Yes |
+`;
+  fs.writeFileSync(path.join(gsdDir, 'DECISIONS.md'), decisionsContent);
+
+  // Verify no DB file exists yet
+  const dbPath = path.join(gsdDir, 'gsd.db');
+  assertTrue(!fs.existsSync(dbPath), 'DB file should not exist before ensureDbOpen');
+
+  // Close any previously open DB
+  try { closeDatabase(); } catch { /* ok */ }
+
+  // Override process.cwd to point at tmpDir for ensureDbOpen
+  const origCwd = process.cwd;
+  process.cwd = () => tmpDir;
+
+  try {
+    // Dynamic import to get the freshest version
+    const { ensureDbOpen } = await import('../bootstrap/dynamic-tools.ts');
+
+    const result = await ensureDbOpen();
+
+    assertTrue(result === true, 'ensureDbOpen should return true when .gsd/ has Markdown');
+    assertTrue(fs.existsSync(dbPath), 'DB file should be created after ensureDbOpen');
+    assertTrue(isDbAvailable(), 'DB should be available after ensureDbOpen');
+
+    // Verify that Markdown migration actually ran
+    const decision = getDecisionById('D001');
+    assertTrue(decision !== null, 'D001 should be migrated from DECISIONS.md');
+    if (decision) {
+      assertEq(decision.scope, 'architecture', 'Migrated decision scope should match');
+      assertEq(decision.choice, 'SQLite', 'Migrated decision choice should match');
+    }
+  } finally {
+    process.cwd = origCwd;
+    closeDatabase();
+    cleanupDir(tmpDir);
+  }
+}
+
+// ═══════════════════════════════════════════════════════════════════════════
+// ensureDbOpen returns false when no .gsd/ exists
+// ═══════════════════════════════════════════════════════════════════════════
+
+console.log('\n── ensureDbOpen: no .gsd/ returns false ──');
+
+{
+  const tmpDir = makeTmpDir();
+  // No .gsd/ directory at all
+
+  try { closeDatabase(); } catch { /* ok */ }
+  const origCwd = process.cwd;
+  process.cwd = () => tmpDir;
+
+  try {
+    const { ensureDbOpen } = await import('../bootstrap/dynamic-tools.ts');
+    const result = await ensureDbOpen();
+    assertTrue(result === false, 'ensureDbOpen should return false when no .gsd/ exists');
+    assertTrue(!isDbAvailable(), 'DB should not be available');
+  } finally {
+    process.cwd = origCwd;
+    cleanupDir(tmpDir);
+  }
+}
+
+// ═══════════════════════════════════════════════════════════════════════════
+// ensureDbOpen opens existing DB without re-migration
+// ═══════════════════════════════════════════════════════════════════════════
+
+console.log('\n── ensureDbOpen: opens existing DB ──');
+
+{
+  const tmpDir = makeTmpDir();
+  const gsdDir = path.join(tmpDir, '.gsd');
+  fs.mkdirSync(gsdDir, { recursive: true });
+
+  // Create a DB file first
+  const dbPath = path.join(gsdDir, 'gsd.db');
+  const { openDatabase } = await import('../gsd-db.ts');
+  openDatabase(dbPath);
+  closeDatabase();
+
+  assertTrue(fs.existsSync(dbPath), 'DB file should exist from manual create');
+
+  const origCwd = process.cwd;
+  process.cwd = () => tmpDir;
+
+  try {
+    const { ensureDbOpen } = await import('../bootstrap/dynamic-tools.ts');
+    const result = await ensureDbOpen();
+    assertTrue(result === true, 'ensureDbOpen should open existing DB');
+    assertTrue(isDbAvailable(), 'DB should be available');
+  } finally {
+    process.cwd = origCwd;
+    closeDatabase();
+    cleanupDir(tmpDir);
+  }
+}
+
+// ═══════════════════════════════════════════════════════════════════════════
+// ensureDbOpen returns false for empty .gsd/ (no Markdown, no DB)
+// ═══════════════════════════════════════════════════════════════════════════
+
+console.log('\n── ensureDbOpen: empty .gsd/ returns false ──');
+
+{
+  const tmpDir = makeTmpDir();
+  fs.mkdirSync(path.join(tmpDir, '.gsd'), { recursive: true });
+  // .gsd/ exists but no DECISIONS.md, REQUIREMENTS.md, or milestones/
+
+  try { closeDatabase(); } catch { /* ok */ }
+  const origCwd = process.cwd;
+  process.cwd = () => tmpDir;
+
+  try {
+    const { ensureDbOpen } = await import('../bootstrap/dynamic-tools.ts');
+    const result = await ensureDbOpen();
+    assertTrue(result === false, 'ensureDbOpen should return false for empty .gsd/');
+  } finally {
+    process.cwd = origCwd;
+    cleanupDir(tmpDir);
+  }
+}
+
+// ═══════════════════════════════════════════════════════════════════════════
+
+report();