Add release note and changelog entry

Author: pedrosousa

src/content/changelogs-next/2025-02-11-custom-errors-beta.mdx

@@ -0,0 +1,50 @@
+---
+title: "Custom Errors (beta): Stored Assets & Account-level Rules"
+description: Cloudflare introduces Custom Errors (beta), building on Custom Error Responses with new asset storage capabilities
+products:
+  - rules
+date: 2025-02-11T11:00:00Z
+---
+
+Cloudflare introduces [Custom Errors](/rules/custom-errors/) (beta), building on Custom Error Responses with new asset storage capabilities. This update allows users to store externally hosted error pages at Cloudflare edge and reference them in custom error rules, eliminating the need to supply inline content.
+
+New capabilities:
+
+- **Custom error assets** – Fetch and store external error pages at the edge for use in error responses.
+- **Account-Level custom errors** – Define error handling rules and assets at the account level for consistency across multiple zones. Zone-level rules take precedence over account-level ones, and assets are not shared between levels.
+
+To store an external error page on the Cloudflare global network, submit a `POST` request to create an asset:
+
+```bash
+curl "https://api.cloudflare.com/client/v4/zones/{zone_id}/custom_pages/assets" \
+--header "Authorization: Bearer <API_TOKEN>" \
+--header 'Content-Type: application/json' \
+--data '{
+  "name": "maintenance",
+  "description": "Maintenance template page",
+  "url": "https://example.com/"
+}'
+```
+
+Then, reference the stored asset in a custom error rule:
+
+```bash
+curl --request PUT \
+"https://api.cloudflare.com/client/v4/zones/{zone_id}/rulesets/phases/http_custom_errors/entrypoint" \
+--header "Authorization: Bearer <API_TOKEN>" \
+--header 'Content-Type: application/json' \
+--data '{
+  "rules": [
+		{
+			"action": "serve_error",
+			"action_parameters": {
+				"asset_name": "maintenance",
+				"content_type": "text/html",
+				"status_code": 503
+			},
+			"enabled": true,
+			"expression": "http.request.uri.path contains \"error\""
+		}
+	]
+}'
+```

src/content/changelogs/rules.yaml

@@ -5,6 +5,10 @@ productLink: "/rules/"
 productArea: Application performance
 productAreaLink: /fundamentals/reference/changelog/performance/
 entries:
+  - publish_date: "2025-02-11"
+    title: "Custom Errors (beta): Stored assets and account-level rules"
+    description: |-
+      Cloudflare introduces [Custom Errors](/rules/custom-errors/) (beta), expanding on Custom Error Responses with new asset storage capabilities. With custom error assets, you can now retrieve and store externally hosted error pages at Cloudflare edge and reference them in custom error rules, eliminating the need to define error content inline. Additionally, Custom Errors now support account-level rules and assets, enabling consistent error handling across multiple zones.
   - publish_date: "2025-01-29"
     title: New Snippets code editor
     description: |-