diff --git a/.dockerignore b/.dockerignore
index 25672b03f..a9aa4e24e 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -15,6 +15,7 @@ uploads
 chart/
 docs/
 docker-compose.yml
+docker-compose.minio-test.yml
 unraid-template.xml
 *.sqlite
 *.sqlite-shm
diff --git a/docker-compose.minio-test.yml b/docker-compose.minio-test.yml
new file mode 100644
index 000000000..2b5315eb5
--- /dev/null
+++ b/docker-compose.minio-test.yml
@@ -0,0 +1,22 @@
+# Local MinIO for the env-gated S3 driver contract suite:
+#   docker compose -f docker-compose.minio-test.yml up -d
+#   cd server && TREK_TEST_S3_ENDPOINT=http://127.0.0.1:9000 \
+#     TREK_TEST_S3_BUCKET=trek-test TREK_TEST_S3_ACCESS_KEY_ID=trekci \
+#     TREK_TEST_S3_SECRET_ACCESS_KEY=trekci-secret \
+#     npx vitest run tests/unit/nest/storage/s3.driver.contract.test.ts
+# 127.0.0.1 is load-bearing: aws-lite picks path-style only for IP/localhost
+# hosts, and stock MinIO only speaks path-style (no MINIO_DOMAIN here).
+services:
+  minio:
+    image: minio/minio:RELEASE.2025-09-07T16-13-09Z # pinned — repo frozen upstream, tag is stable
+    command: server /data
+    ports:
+      - "9000:9000"
+    environment:
+      - MINIO_ROOT_USER=trekci
+      - MINIO_ROOT_PASSWORD=trekci-secret
+    healthcheck:
+      test: ["CMD", "mc", "ready", "local"] # curl was removed from the image
+      interval: 2s
+      timeout: 5s
+      retries: 15
diff --git a/server/tests/unit/nest/storage/s3.driver.contract.test.ts b/server/tests/unit/nest/storage/s3.driver.contract.test.ts
new file mode 100644
index 000000000..39fcce00f
--- /dev/null
+++ b/server/tests/unit/nest/storage/s3.driver.contract.test.ts
@@ -0,0 +1,71 @@
+import { describe, beforeAll } from 'vitest';
+import { randomUUID } from 'node:crypto';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import awsLite from '@aws-lite/client';
+import { S3Driver } from '../../../../src/nest/storage/drivers/s3.driver';
+import { describeStorageDriver, type DriverHarness } from './storage-driver.contract';
+
+/**
+ * Env-gated: engages only when TREK_TEST_S3_* is set (CI's MinIO job; locally
+ * via `docker compose -f docker-compose.minio-test.yml up`). Local runs stay
+ * hermetic. Deviation from local/mirror's bare top-level call: the gate must
+ * wrap describeStorageDriver because the contract file owns its own describe.
+ */
+const endpoint = process.env.TREK_TEST_S3_ENDPOINT;
+const bucket = process.env.TREK_TEST_S3_BUCKET ?? 'trek-test';
+const accessKeyId = process.env.TREK_TEST_S3_ACCESS_KEY_ID ?? 'trekci';
+const secretAccessKey = process.env.TREK_TEST_S3_SECRET_ACCESS_KEY ?? 'trekci-secret';
+
+describe.skipIf(!endpoint)('S3Driver against MinIO', () => {
+  beforeAll(async () => {
+    // Idempotent bucket setup — raw client, driver stays bucket-agnostic.
+    const client = await awsLite({
+      accessKeyId,
+      secretAccessKey,
+      region: 'us-east-1',
+      endpoint: endpoint!,
+      retries: 1,
+      keepAlive: false,
+      plugins: [await import('@aws-lite/s3')],
+    });
+    await client.S3.CreateBucket({ Bucket: bucket }).catch((err: { code?: string; statusCode?: number }) => {
+      if (err.code !== 'BucketAlreadyOwnedByYou' && err.statusCode !== 409) throw err;
+    });
+  });
+
+  async function makeHarness(): Promise<DriverHarness> {
+    // Fresh namespace per test (makeHarness runs in beforeEach) — reruns
+    // against a shared MinIO never collide; cleanup removes everything.
+    const keyPrefix = `contract-${randomUUID()}`;
+    const tmpDir = await fs.promises.mkdtemp(path.join(os.tmpdir(), 'trek-s3-contract-'));
+    const driver = new S3Driver({
+      id: 's3-contract',
+      endpoint: endpoint!,
+      region: 'us-east-1',
+      bucket,
+      keyPrefix,
+      accessKeyId,
+      secretAccessKey,
+      retries: 1,
+      timeoutMs: 10000,
+      keepAlive: false, // vitest forks must exit promptly
+    });
+    let counter = 0;
+    return {
+      driver,
+      async makeTempFile(contents) {
+        const p = path.join(tmpDir, `src-${counter++}.bin`);
+        await fs.promises.writeFile(p, contents);
+        return p;
+      },
+      async cleanup() {
+        for await (const stat of driver.list('')) await driver.delete(stat.key);
+        await fs.promises.rm(tmpDir, { recursive: true, force: true });
+      },
+    };
+  }
+
+  describeStorageDriver('S3Driver', makeHarness);
+});