diff --git a/docs/assets/threading-guardrails.yaml b/docs/assets/threading-guardrails.yaml
new file mode 100644
index 0000000..ac9e1a8
--- /dev/null
+++ b/docs/assets/threading-guardrails.yaml
@@ -0,0 +1,18 @@
+rules:
+  - description: "Avoid raw threading.Thread; prefer ThreadPoolExecutor"
+    enabled: true
+    severity: "medium"
+    event_types: ["pull_request"]
+    parameters:
+      file_patterns: ["**/*.py"]
+      forbidden_patterns:
+        - "threading\\.Thread"
+
+  - description: "Warn when ThreadPoolExecutor max_workers is greater than 10"
+    enabled: true
+    severity: "medium"
+    event_types: ["pull_request"]
+    parameters:
+      file_patterns: ["**/*.py"]
+      forbidden_patterns:
+        - "ThreadPoolExecutor\\(max_workers\\s*=\\s*(1[1-9]|[2-9][0-9]|\\d{3,})"
diff --git a/docs/getting-started/diff-rule-presets.md b/docs/getting-started/diff-rule-presets.md
new file mode 100644
index 0000000..64319cf
--- /dev/null
+++ b/docs/getting-started/diff-rule-presets.md
@@ -0,0 +1,36 @@
+# Diff rule presets (threading guardrails)
+
+These presets use the diff-aware validators already supported by Watchflow. Paste them directly into `.watchflow/rules.yaml` or upload to watchflow.dev as a YAML file. They avoid any unsupported sections (no `actions`, only `description`, `enabled`, `severity`, `event_types`, and `parameters` with `file_patterns`, `require_patterns`, `forbidden_patterns`).
+
+## Preset file
+
+The file `docs/assets/threading-guardrails.yaml` contains ready-to-use rules:
+
+```yaml
+rules:
+  - description: "Avoid raw threading.Thread; prefer ThreadPoolExecutor"
+    enabled: true
+    severity: "medium"
+    event_types: ["pull_request"]
+    parameters:
+      file_patterns: ["**/*.py"]
+      forbidden_patterns:
+        - "threading\\.Thread"
+
+  - description: "Warn when ThreadPoolExecutor max_workers is greater than 10"
+    enabled: true
+    severity: "medium"
+    event_types: ["pull_request"]
+    parameters:
+      file_patterns: ["**/*.py"]
+      forbidden_patterns:
+        - "ThreadPoolExecutor\\(max_workers\\s*=\\s*(1[1-9]|[2-9][0-9]|\\d{3,})"
+```
+
+## How to use on watchflow.dev
+
+1) Click “Upload config” (or paste the YAML directly if enabled).
+2) Ensure event type is `pull_request`.
+3) Adjust file globs or regexes as needed for your repo.
+
+If the form still shows “Rule not supported,” it means the UI is filtering diff-pattern rules. In that case, use the YAML upload path or apply the config directly in your repo. A follow-up change to the site can whitelist these presets so they appear without warnings.
diff --git a/mkdocs.yml b/mkdocs.yml
index 8298626..398de32 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -62,6 +62,7 @@ nav:
   - Getting Started:
     - Quick Start: getting-started/quick-start.md
     - Configuration: getting-started/configuration.md
+    - Diff Rule Presets: getting-started/diff-rule-presets.md
   - Features & Capabilities:
     - Features: features.md
     - Comparative Analysis: benchmarks.md