docs: add Google Cloud Model Armor guardrail documentation (#12814)

- Add comprehensive documentation for Model Armor integration
- Include configuration examples and parameter descriptions
- Add Model Armor to sidebars navigation
- Document authentication methods and error handling

docs/my-website/docs/proxy/guardrails/model_armor.md

@@ -0,0 +1,93 @@
+import Image from '@theme/IdealImage';
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+# Google Cloud Model Armor
+
+LiteLLM supports Google Cloud Model Armor guardrails via the [Model Armor API](https://cloud.google.com/security-command-center/docs/model-armor-overview). 
+
+
+## Supported Guardrails
+
+- [Model Armor Templates](https://cloud.google.com/security-command-center/docs/manage-model-armor-templates) - Content sanitization and blocking based on configured templates
+
+## Quick Start
+### 1. Define Guardrails on your LiteLLM config.yaml 
+
+Define your guardrails under the `guardrails` section
+
+```yaml
+model_list:
+  - model_name: gpt-3.5-turbo
+    litellm_params:
+      model: openai/gpt-3.5-turbo
+      api_key: os.environ/OPENAI_API_KEY
+
+guardrails:
+  - guardrail_name: model-armor-shield
+    litellm_params:
+      guardrail: model_armor
+      mode: [pre_call, post_call]  # Run on both input and output
+      template_id: "your-template-id"  # Required: Your Model Armor template ID
+      project_id: "your-project-id"    # Your GCP project ID
+      location: "us-central1"          # GCP location (default: us-central1)
+      credentials: "path/to/credentials.json"  # Path to service account key
+      mask_request_content: true       # Enable request content masking
+      mask_response_content: true      # Enable response content masking
+      fail_on_error: true             # Fail request if Model Armor errors (default: true)
+      default_on: true                # Run by default for all requests
+```
+
+#### Supported values for `mode`
+
+- `pre_call` Run **before** LLM call, on **input**
+- `post_call` Run **after** LLM call, on **input & output**
+
+### 2. Start LiteLLM Gateway 
+
+
+```shell
+litellm --config config.yaml --detailed_debug
+```
+
+### 3. Test request 
+
+**[Langchain, OpenAI SDK Usage Examples](../proxy/user_keys#request-format)**
+
+```shell
+curl -i http://localhost:4000/v1/chat/completions \
+  -H "Content-Type: application/json" \
+  -H "Authorization: Bearer sk-npnwjPQciVRok5yNZgKmFQ" \
+  -d '{
+    "model": "gpt-3.5-turbo",
+    "messages": [
+      {"role": "user", "content": "Hi, my email is test@example.com"}
+    ],
+    "guardrails": ["model-armor-shield"]
+  }'
+```
+
+## Supported Params 
+
+### Common Params
+
+- `api_key` - str - Google Cloud service account credentials (optional if using ADC)
+- `api_base` - str - Custom Model Armor API endpoint (optional)
+- `default_on` - bool - Whether to run the guardrail by default. Default is `false`.
+- `mode` - Union[str, list[str]] - Mode to run the guardrail. Either `pre_call` or `post_call`. Default is `pre_call`.
+
+### Model Armor Specific
+
+- `template_id` - str - The ID of your Model Armor template (required)
+- `project_id` - str - Google Cloud project ID (defaults to credentials project)
+- `location` - str - Google Cloud location/region. Default is `us-central1`
+- `credentials` - Union[str, dict] - Path to service account JSON file or credentials dictionary
+- `api_endpoint` - str - Custom API endpoint for Model Armor (optional)
+- `fail_on_error` - bool - Whether to fail requests if Model Armor encounters errors. Default is `true`
+- `mask_request_content` - bool - Enable masking of sensitive content in requests. Default is `false`
+- `mask_response_content` - bool - Enable masking of sensitive content in responses. Default is `false`
+
+
+## Further Reading
+
+- [Control Guardrails per API Key](./quick_start#-control-guardrails-per-api-key)

docs/my-website/sidebars.js

@@ -39,6 +39,7 @@ const sidebars = {
           "proxy/guardrails/lasso_security",
           "proxy/guardrails/guardrails_ai",
           "proxy/guardrails/lakera_ai",
+          "proxy/guardrails/model_armor",
           "proxy/guardrails/openai_moderation",
           "proxy/guardrails/pangea",
           "proxy/guardrails/pii_masking_v2",