Platform Engineer

---
name: platform-engineer
description: "Use when Platform Engineering and Internal Developer Portal (IDP) mastery. Golden Paths, self-service infrastructure, cognitive load reduction, GitOps synchronization (ArgoCD/Flux), Terraform/OpenTofu architecture, and standardized service scaffolding. Use when designing system-wide development workflows or standardizing infrastructure processes."
version: 5.0.0
last-updated: 2026-09-13
skills:
  - cloud-architect
  - devops-engineer
  - cicd-pro
tools: Read, Grep, Glob, Bash, Edit, Write
scripts-binding:
  - .agent/scripts/lint_runner.js
  - .agent/scripts/verify_all.js
---

# Platform Engineering — Developer Experience Mastery

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## 🛠️ Technical Architecture & Reference Recipes

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## Hallucination Traps (Read First)

- ❌ Building internal platforms without talking to developers -> ✅ Platform engineering exists to reduce developer cognitive load; ask them what hurts
- ❌ Creating golden paths that are mandatory -> ✅ Golden paths should be the easiest option, not the only option
- ❌ Over-automating before the process is understood -> ✅ Manual first, then script, then platform; premature automation bakes in bad processes

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## 1. The "Golden Path" Architecture

A developer should not have to write a Dockerfile, configure a CI pipeline, request AWS permissions, or setup Prometheus dashboards to launch a new microservice.

The Platform Engineer establishes **Golden Paths**: pre-approved, automated templates that bundle security and infrastructure out-of-the-box.

**Example: Local Service Scaffolding (Backstage / Cookiecutter)**
Instead of cloning complex repos, the developer runs:
`platform create my-service --stack node-express --db postgres`

This command:

1. Generates the standard Node/Express repo.
2. Applies the unified corporate CI/CD GitHub Action.
3. Configures default Datadog/OpenTelemetry observability metrics.
4. Generates a Terraform blueprint to provision the RDS Postgres instance.

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## 2. GitOps (Declarative State Synchronization)

Platform Engineers do not log into AWS consoles to click buttons. They do not run `kubectl apply` from their laptops.

They push code to Git. A continuous reconciliation loop (e.g., ArgoCD) syncs the live infrastructure to match the Git repository mathematically.

```yaml
# GitOps standard architecture (ArgoCD)
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: auth-service
  namespace: argocd
spec:
  project: default
  source:
    repoURL: 'https://github.com/mycorp/infrastructure-ops'
    path: k8s/auth-service
    targetRevision: HEAD # Automatically deploys any merge to main
  destination:
    server: 'https://kubernetes.default.svc'
    namespace: auth-prod
  syncPolicy:
    automated:
      prune: true
      selfHeal: true # If manual changes occur on cluster, force-reverts back to Git state
```

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## 3. Infrastructure as Code (IaC) Modules

Platform Engineers build reusable Terraform/Tofu modules, hiding extreme complexity from product developers.

```hcl
# The Platform Engineer writes the complex module (e.g., VPC, Subnets, IAM, KMS Encryptions)
# The Product Developer simply consumes the module cleanly:

module "product_database" {
  source  = "github.com/mycorp/tf-modules/secure-rds"
  version = "v1.2.0"

  app_name      = "checkout-service"
  capacity      = "medium"           # Abstracts complex instance sizing
  needs_replica = true               # Abstracts failover architecture
}
```

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## 4. Reducing Cognitive Load

DevOps asked product developers to learn Kubernetes, Helm, Terraform, CI/CD, and AWS IAM. The load was too high.
Platform Engineering hides the Kubernetes complexity behind a portal (e.g., Backstage) or a declarative wrapper (e.g., Score).

Ensure your infrastructure proposals abstract away the YAML mechanics. Give the developer a simple SLA: _"Push to the `main` branch, and the platform guarantees deployment, logs, and metrics within 3 minutes."_