Create byo-agentgateway guide

docs-site/assets/conrefs/snippets/field-desc/review-table.md

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+Review the following table to understand this configuration.

docs-site/content/kagent/supported-providers/byo-agentgateway.md

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+---
+title: Agentgateway
+description: Configure an agentgateway deployment as a model endpoint for kagent.
+weight: 9
+author: kagent.dev
+---
+
+You can route model requests through an [agentgateway](https://agentgateway.dev/docs/) deployment. Agentgateway is an AI-native proxy that provides traffic management, observability, and security for LLM calls. Because agentgateway exposes an OpenAI-compatible API, you configure the `ModelConfig` with `provider: OpenAI` and set `openAI.baseUrl` to your agentgateway Gateway service address.
+
+## Set up agentgateway model routing {#setup}
+
+> [!NOTE]
+> The `AgentgatewayModel` feature is experimental and disabled by default. You must enable it when you install agentgateway by passing `--set agentgatewayModels.enabled=true` to the control plane Helm chart.
+
+1. Install agentgateway in your cluster. For more information, see the [agentgateway documentation](https://agentgateway.dev/docs/kubernetes/latest/setup/). Add `--set agentgatewayModels.enabled=true` to the Helm command for the agentgateway control plane.
+
+2. Create a `Gateway` resource for model routing.
+   ```yaml
+   kubectl apply -f - <<EOF
+   apiVersion: gateway.networking.k8s.io/v1
+   kind: Gateway
+   metadata:
+     name: agentgateway-proxy
+     namespace: agentgateway-system
+   spec:
+     gatewayClassName: agentgateway
+     listeners:
+     - name: http
+       protocol: HTTP
+       port: 80
+       allowedRoutes:
+         namespaces:
+           from: All
+         kinds:
+         - group: gateway.networking.k8s.io
+           kind: HTTPRoute
+         - group: agentgateway.dev
+           kind: AgentgatewayModel
+   EOF
+   ```
+
+3. Create an `AgentgatewayModel` resource for each model that you want kagent to access. The resource name becomes the model name that kagent sends in requests, so it must match `spec.model` in the kagent `ModelConfig`. The following example routes requests for `gpt-4o-mini` to the OpenAI provider. For more provider options and authentication configuration, see the [agentgateway model documentation](https://docs.solo.io/agentgateway/latest/llm/models/).
+   ```yaml
+   kubectl apply -f - <<EOF
+   apiVersion: agentgateway.dev/v1alpha1
+   kind: AgentgatewayModel
+   metadata:
+     name: gpt-4o-mini
+     namespace: agentgateway-system
+   spec:
+     parentRefs:
+     - group: gateway.networking.k8s.io
+       kind: Gateway
+       name: agentgateway-proxy
+       sectionName: http
+     provider: OpenAI
+   EOF
+   ```
+
+4. Save the agentgateway Gateway service address in an environment variable.
+   ```sh
+   export AGENTGATEWAY_URL=http://agentgateway-proxy.agentgateway-system.svc.cluster.local
+   ```
+
+## Connect to an agentgateway endpoint {#connect}
+
+1. Create a `ModelConfig` resource. Choose the tab that matches your agentgateway authentication configuration.
+
+   {{< tabs >}}
+   {{% tab name="No authentication" %}}
+   If your agentgateway deployment does not enforce any API key authentication, apply the following `ModelConfig`.
+   ```yaml
+   kubectl apply -f - <<EOF
+   apiVersion: kagent.dev/v1alpha2
+   kind: ModelConfig
+   metadata:
+     name: agentgateway-model
+     namespace: kagent
+   spec:
+     provider: OpenAI
+     model: gpt-4o-mini
+     openAI:
+       baseUrl: "$AGENTGATEWAY_URL"
+   EOF
+   ```
+
+   {{< reuse "conrefs/snippets/field-desc/review-table.md" >}} For more information, see the [API docs](https://kagent.dev/docs/kagent/resources/api-ref#modelconfigspec).
+
+   | Setting | Description |
+   | --- | --- |
+   | `provider` | Set to `OpenAI`, because agentgateway exposes an OpenAI-compatible API. |
+   | `model` | The model name to request from agentgateway. This value must match the name of an `AgentgatewayModel` resource in your agentgateway deployment. |
+   | `openAI.baseUrl` | The Kubernetes service address of your agentgateway Gateway, set in `$AGENTGATEWAY_URL`. |
+   {{% /tab %}}
+   {{% tab name="API key authentication" %}}
+   If your agentgateway deployment applies an `apiKeyAuthentication` policy with `mode: Strict`, you must provide an API key in the `ModelConfig`.
+
+   1. Save the API key that the agentgateway `apiKeyAuthentication` policy requires. This is the key that clients must send in the `Authorization` header when they call agentgateway. Create a Kubernetes secret in the same namespace as your agent, such as `kagent`.
+      ```bash
+      export AGENTGATEWAY_API_KEY=<your-api-key>
+      kubectl create secret generic kagent-agentgateway-key -n kagent \
+        --from-literal AGENTGATEWAY_API_KEY=$AGENTGATEWAY_API_KEY
+      ```
+
+   2. Create the `ModelConfig` resource.
+      ```yaml
+      kubectl apply -f - <<EOF
+      apiVersion: kagent.dev/v1alpha2
+      kind: ModelConfig
+      metadata:
+        name: agentgateway-model
+        namespace: kagent
+      spec:
+        provider: OpenAI
+        model: gpt-4o-mini
+        apiKeySecret: kagent-agentgateway-key
+        apiKeySecretKey: AGENTGATEWAY_API_KEY
+        openAI:
+          baseUrl: "$AGENTGATEWAY_URL"
+      EOF
+      ```
+
+   {{< reuse "conrefs/snippets/field-desc/review-table.md" >}} For more information, see the [API docs](https://kagent.dev/docs/kagent/resources/api-ref#modelconfigspec).
+
+   | Setting | Description |
+   | --- | --- |
+   | `provider` | Set to `OpenAI`, because agentgateway exposes an OpenAI-compatible API. |
+   | `model` | The model name to request from agentgateway. This value must match the name of an `AgentgatewayModel` resource in your agentgateway deployment. |
+   | `apiKeySecret` | The name of the Kubernetes secret that stores your agentgateway API key. |
+   | `apiKeySecretKey` | The key in the secret that stores your API key. |
+   | `openAI.baseUrl` | The Kubernetes service address of your agentgateway Gateway, set in `$AGENTGATEWAY_URL`. |
+   {{% /tab %}}
+   {{< /tabs >}}
+
+2. Verify that the `ModelConfig` is accepted.
+   ```bash
+   kubectl get modelconfig agentgateway-model -n kagent -o yaml
+   ```
+
+Agentgateway is now added as a model endpoint in kagent. Next, you can [create or update an agent](https://kagent.dev/docs/kagent/getting-started/first-agent) to use this model.