diff --git a/app/api/activities/readme.md b/app/api/activities/readme.md
new file mode 100644
index 0000000..cfa2095
--- /dev/null
+++ b/app/api/activities/readme.md
@@ -0,0 +1,126 @@
+# Activities API Documentation
+
+## Overview
+The Activities API provides event tracking data for short URLs. It allows retrieving visitor activity information based on various filters such as URL slug, domain, and date ranges.
+
+## Endpoint
+```
+GET /api/activities
+```
+
+## Request Parameters
+
+| Parameter  | Type    | Required | Description |
+|------------|---------|----------|-------------|
+| `slug`     | string  | No*      | The short URL slug to filter events by |
+| `domain`   | string  | No*      | The domain to filter events by |
+| `startTime`| string  | No*      | Start time for date range filter (ISO format) |
+| `endTime`  | string  | No*      | End time for date range filter (ISO format) |
+| `page`     | integer | No       | Page number for pagination (default: 1) |
+| `pageSize` | integer | No       | Number of records per page (default: 50) |
+| `format`   | string  | No       | Response format, set to 'csv' for CSV output (default: JSON) |
+
+\* Either `slug`+`domain` combination OR at least one of `startTime`/`endTime` must be provided.
+
+## Response Formats
+
+### JSON Format (Default)
+JSON responses include the following structure:
+
+```json
+{
+  "success": true,
+  "data": [
+    {
+      "id": "event-id",
+      "type": "event-type",
+      "time": "timestamp",
+      "visitor": {
+        "id": "visitor-id",
+        "ipAddress": "ip-address",
+        "userAgent": "user-agent-string",
+        "referrer": "referrer-url"
+      },
+      "device": {
+        "type": "device-type",
+        "browser": "browser-name",
+        "os": "operating-system"
+      },
+      "location": {
+        "country": "country-code",
+        "city": "city-name"
+      },
+      "link": {
+        "id": "link-id",
+        "slug": "link-slug",
+        "originalUrl": "original-url",
+        "label": "link-label",
+        "tags": ["tag1", "tag2"]
+      },
+      "utm": {
+        "source": "utm-source",
+        "medium": "utm-medium",
+        "campaign": "utm-campaign",
+        "term": "utm-term",
+        "content": "utm-content"
+      }
+    }
+  ],
+  "meta": {
+    "total": 100,
+    "page": 1,
+    "pageSize": 50
+  }
+}
+```
+
+In case of an error:
+```json
+{
+  "success": false,
+  "data": null,
+  "error": "Error message description"
+}
+```
+
+### CSV Format
+When `format=csv` is specified, the response is returned as plain text in CSV format with the following columns:
+- `time`: Timestamp of the event
+- `activity`: Type of activity/event
+- `campaign`: UTM campaign value (defaults to "demo" if not found)
+- `clientId`: Visitor ID
+- `originPath`: Original request path or referrer URL
+
+## Examples
+
+### Get activities for a specific short URL
+```
+GET /api/activities?slug=promo123&domain=googleads.link
+```
+
+### Get activities within a date range
+```
+GET /api/activities?startTime=2023-06-01T00:00:00Z&endTime=2023-06-30T23:59:59Z
+```
+
+### Get events as CSV
+```
+GET /api/activities?slug=promo123&domain=googleads.link&format=csv
+```
+
+### Pagination example
+```
+GET /api/activities?slug=promo123&domain=googleads.link&page=2&pageSize=20
+```
+
+## Error Codes
+
+| Status Code | Description |
+|-------------|-------------|
+| 400         | Missing required parameters |
+| 500         | Server error while processing the request |
+
+## Notes
+- For privacy and security reasons, some fields may be omitted or anonymized based on user settings.
+- The CSV format is optimized for easy import into spreadsheet applications.
+- When using the CSV format, the response is returned as plain text rather than a downloadable file.
diff --git a/app/api/activities/route.ts b/app/api/activities/route.ts
index d62a426..69c8dfc 100644
--- a/app/api/activities/route.ts
+++ b/app/api/activities/route.ts
@@ -38,12 +38,19 @@ export async function GET(request: NextRequest) {
     const startTime = searchParams.get('startTime') || undefined;
     const endTime = searchParams.get('endTime') || undefined;
     
-    // 修改验证逻辑，允许只使用时间范围
-    // 现在只需要确保有足够的过滤条件
+    // Check if either slug or domain is provided without the other
+    if ((slug && !domain) || (!slug && domain)) {
+      return NextResponse.json({
+        success: false,
+        error: 'Both slug and domain parameters must be provided together'
+      }, { status: 400 });
+    }
+    
+    // Ensure either slug+domain or date range is provided
     if ((!slug && !domain) && (!startTime && !endTime)) {
       return NextResponse.json({
         success: false,
-        error: 'Missing filter parameters: provide either slug/domain or date range'
+        error: 'Missing filter parameters: provide either slug+domain or date range'
       }, { status: 400 });
     }