diff --git a/src/__tests__/db/settings.test.ts b/src/__tests__/db/settings.test.ts
new file mode 100644
index 0000000..581801a
--- /dev/null
+++ b/src/__tests__/db/settings.test.ts
@@ -0,0 +1,33 @@
+import { getDb, resetDb } from '../../db';
+import { getSetting, setSetting, getAllSettings } from '../../db/settings';
+
+beforeEach(() => {
+  resetDb();
+});
+
+describe('settings', () => {
+  it('returns null for a missing key', () => {
+    const db = getDb();
+    expect(getSetting(db, 'missing')).toBeNull();
+  });
+
+  it('sets and gets a value', () => {
+    const db = getDb();
+    setSetting(db, 'model', 'gpt-4o-mini');
+    expect(getSetting(db, 'model')).toBe('gpt-4o-mini');
+  });
+
+  it('overwrites an existing value', () => {
+    const db = getDb();
+    setSetting(db, 'model', 'gpt-4o-mini');
+    setSetting(db, 'model', 'gemini-flash');
+    expect(getSetting(db, 'model')).toBe('gemini-flash');
+  });
+
+  it('returns all settings as an object', () => {
+    const db = getDb();
+    setSetting(db, 'a', '1');
+    setSetting(db, 'b', '2');
+    expect(getAllSettings(db)).toEqual({ a: '1', b: '2' });
+  });
+});
diff --git a/src/db/settings.ts b/src/db/settings.ts
new file mode 100644
index 0000000..c13a83b
--- /dev/null
+++ b/src/db/settings.ts
@@ -0,0 +1,15 @@
+import type { Database } from 'better-sqlite3';
+
+export function getSetting(db: Database, key: string): string | null {
+  const row = db.prepare('SELECT value FROM settings WHERE key = ?').get(key) as { value: string } | undefined;
+  return row?.value ?? null;
+}
+
+export function setSetting(db: Database, key: string, value: string): void {
+  db.prepare('INSERT OR REPLACE INTO settings (key, value) VALUES (?, ?)').run(key, value);
+}
+
+export function getAllSettings(db: Database): Record<string, string> {
+  const rows = db.prepare('SELECT key, value FROM settings').all() as Array<{ key: string; value: string }>;
+  return Object.fromEntries(rows.map(r => [r.key, r.value]));
+}