feat: Add AGENTS.md file (#692)

As developers, we are curious. As humans, we use tools. As human developers, we are curious about tools. Signed-off-by: Jonathan Stacks <jonstacks@users.noreply.github.com>
2026-05-17 16:50:44 +00:00 · 2025-10-28 15:27:41 -05:00
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+# AGENTS.md - ngrok Kubernetes Operator
+
+The ngrok-operator is a Kubernetes Operator that reconciles:
+
+- Service resources of `Type=LoadBalancer`
+- Ingress resources
+- Gateway API resources
+- ngrok CRDs
+
+## Quick Facts
+
+- **Module**: `github.com/ngrok/ngrok-operator`
+- **Type**: Kubernetes Operator (kubebuilder v4, multigroup)
+- **Domain**: `k8s.ngrok.com`
+- **Language**: Go
+
+## Entry Points & Modes
+
+- **[main.go](main.go)** → `cmd.Execute()`
+- **[cmd/](cmd/)** contains three operational modes:
+  - `api-manager.go` - Manages ngrok resources via ngrok API (CRDs → ngrok API)
+  - `agent-manager.go` - Runs ngrok agents in-cluster for tunneling
+  - `bindings-forwarder-manager.go` - Manages service bindings and forwarding
+
+## Directory Map
+
+```
+api/<group>/v1alpha1/        # CRD definitions (ingress, ngrok, bindings)
+internal/controller/<group>/ # Reconcilers organized by API group
+internal/controller/base_controller.go  # Common CRUD/finalizers/status helpers
+internal/ngrokapi/           # ngrok API client wrappers
+internal/ir/                 # Intermediate representation (K8s → ngrok API)
+internal/store/              # State management and caching
+pkg/managerdriver/           # Manager driver implementations
+pkg/bindingsdriver/          # Bindings driver implementations
+cmd/                         # CLI and manager entry points
+config/                      # Kustomize manifests (CRDs, RBAC, etc.)
+helm/ngrok-operator/         # Helm chart
+```
+
+## Resource → Controller Map
+
+| API Group | Resources | Controller Location |
+|-----------|-----------|---------------------|
+| **ingress.k8s.ngrok.com/v1alpha1** | Domain, IPPolicy | [internal/controller/ingress/](internal/controller/ingress/) |
+| **ingress.k8s.ngrok.com/v1alpha1** | Ingress (networking.k8s.io/v1) | [internal/controller/ingress/](internal/controller/ingress/) |
+| **ngrok.k8s.ngrok.com/v1alpha1** | NgrokTrafficPolicy, KubernetesOperator | [internal/controller/ngrok/](internal/controller/ngrok/) |
+| **bindings.k8s.ngrok.com/v1alpha1** | BindingConfiguration, BoundEndpoint | [internal/controller/bindings/](internal/controller/bindings/) |
+| **gateway.networking.k8s.io/v1** | Gateway, GatewayClass, HTTPRoute, TLSRoute, TCPRoute | [internal/controller/gateway/](internal/controller/gateway/) |
+| **core/v1** | Service | [internal/controller/service/](internal/controller/service/) |
+| **agent** | AgentEndpoint | [internal/controller/agent/](internal/controller/agent/) |
+
+## Core Patterns
+
+- **BaseController** ([internal/controller/base_controller.go](internal/controller/base_controller.go)) - Common CRUD operations, finalizer management, status updates
+- **IR** ([internal/ir/](internal/ir/)) - Translates Kubernetes resources to ngrok API concepts
+- **Store** ([internal/store/](internal/store/)) - State and caching across reconcilers
+- **Drivers** ([pkg/managerdriver/](pkg/managerdriver/), [pkg/bindingsdriver/](pkg/bindingsdriver/)) - Abstracts operational modes
+
+## Development Workflow
+
+```bash
+make help                   # List all available targets
+make generate               # Generate DeepCopy methods
+make manifests              # Generate CRDs, RBAC, webhooks
+make build                  # Build binaries
+make test                   # Run unit tests
+make e2e-tests              # Run E2E tests
+make run                    # Run locally (uses kubeconfig)
+make deploy                 # Deploy to cluster
+make undeploy               # Remove from cluster
+```
+
+## Configuration
+
+- **Credentials**: `helm install` requires `credentials.apiKey` and `credentials.authtoken`
+- **Feature Flags**: `useExperimentalGatewayApi=true` enables Gateway API support
+
+## Rules
+
+- Always register new APIs with `AddToScheme` in manager setup
+- Update RBAC markers (`// +kubebuilder:rbac:...`) when adding permissions
+- Use status subresource (`r.Status().Update()`) for status-only updates
+- Manage finalizers on resource deletion to clean up external resources
+- Requeue on transient ngrok API errors (return `ctrl.Result{Requeue: true}`)
+- Prefer `BaseController` helpers over raw client operations
+