Imported from jeremylongshore/tons-of-skills-marketplace (skills/.curated/castai-hello-world/SKILL.md). Install upstream with npx skills add jeremylongshore/tons-of-skills-marketplace --skill castai-hello-world. Copyright stays with the author (MIT).

CAST AI Hello World

Overview

First API calls against the CAST AI REST API: list connected clusters, retrieve the savings report, and inspect node inventory. All examples use curl with the X-API-Key header -- no SDK required.

Prerequisites

• Completed castai-install-auth setup
• CASTAI_API_KEY environment variable set
• At least one cluster connected to CAST AI

Instructions

Step 1: List Connected Clusters

curl -s -H "X-API-Key: ${CASTAI_API_KEY}" \
  https://api.cast.ai/v1/kubernetes/external-clusters \
  | jq '.items[] | {id, name, status, providerType}'

Expected output:

{
  "id": "abc123-def456",
  "name": "production-eks",
  "status": "ready",
  "providerType": "eks"
}

Step 2: Get Cluster Savings Report

export CASTAI_CLUSTER_ID="your-cluster-id"

# Current month savings
curl -s -H "X-API-Key: ${CASTAI_API_KEY}" \
  "https://api.cast.ai/v1/kubernetes/clusters/${CASTAI_CLUSTER_ID}/savings" \
  | jq '{
    monthlySavings: .monthlySavings,
    savingsPercentage: .savingsPercentage,
    currentCost: .currentMonthlyCost,
    optimizedCost: .optimizedMonthlyCost
  }'

Step 3: List Cluster Nodes

curl -s -H "X-API-Key: ${CASTAI_API_KEY}" \
  "https://api.cast.ai/v1/kubernetes/external-clusters/${CASTAI_CLUSTER_ID}/nodes" \
  | jq '.items[] | {
    name: .name,
    instanceType: .instanceType,
    lifecycle: .lifecycle,
    cpu: .allocatableCpu,
    memory: .allocatableMemory,
    zone: .zone
  }'

Step 4: Check Autoscaler Policies

curl -s -H "X-API-Key: ${CASTAI_API_KEY}" \
  "https://api.cast.ai/v1/kubernetes/clusters/${CASTAI_CLUSTER_ID}/policies" \
  | jq '{
    enabled: .enabled,
    unschedulablePods: .unschedulablePods.enabled,
    nodeDownscaler: .nodeDownscaler.enabled,
    spotInstances: .spotInstances.enabled
  }'

Output

The first read-only run returns a list of connected clusters, a monthly-savings snapshot, node inventory, and autoscaler-policy state. Save only the fields needed for the onboarding record; cluster names, account metadata, and spend data should be treated as environment-sensitive operational information.

Examples

Run the cluster-list command against a non-production key, select one expected cluster ID, then request its node inventory and policy state. A successful onboarding result shows the expected cluster name and an online agent; a 401 or offline agent is a stop condition, not a reason to retry with a broader key.

Error Handling

Resources

• CAST AI API Reference
• CAST AI Console
• Savings Report Docs

Next Steps

Proceed to castai-local-dev-loop to set up a development workflow.