Azure Resource Graph Queries for Cost Optimization

Azure Resource Graph (ARG) enables fast, cross-subscription resource querying using KQL via az graph query. Use it to find orphaned resources, unused infrastructure, and optimization targets.

How to Query

Use the extension_cli_generate MCP tool to generate az graph query commands:

azure__extension_cli_generate
  intent: "query Azure Resource Graph to <describe what you want to find>"
  cli-type: "az"

Or construct directly:

az graph query -q "<KQL>" --query "data[].{name:name, type:type}" -o table

⚠️ Prerequisite: az extension add --name resource-graph

Key Tables

Cost Optimization Query Patterns

Find orphaned (unattached) managed disks:

Resources
| where type =~ 'microsoft.compute/disks'
| where isempty(managedBy)
| project name, resourceGroup, location, diskSizeGb=properties.diskSizeGB, sku=sku.name

Find unattached public IP addresses:

Resources
| where type =~ 'microsoft.network/publicipaddresses'
| where isempty(properties.ipConfiguration)
| project name, resourceGroup, location, sku=sku.name

Find orphaned network interfaces:

Resources
| where type =~ 'microsoft.network/networkinterfaces'
| where isempty(properties.virtualMachine)
| project name, resourceGroup, location

Resource count by SKU/tier (spot oversized resources):

Resources
| where isnotempty(sku.name)
| summarize count() by type, tostring(sku.name)
| order by count_ desc

Tag coverage for cost allocation:

Resources
| extend hasCostCenter = isnotnull(tags['CostCenter'])
| summarize total=count(), tagged=countif(hasCostCenter) by type
| extend coverage=round(100.0 * tagged / total, 1)
| order by total desc

Find idle load balancers (no backend pools):

Resources
| where type =~ 'microsoft.network/loadbalancers'
| where array_length(properties.backendAddressPools) == 0
| project name, resourceGroup, location, sku=sku.name

Get Advisor cost recommendations:

AdvisorResources
| where properties.category == 'Cost'
| project name, impact=properties.impact, description=properties.shortDescription.solution

Tips

• Use =~ for case-insensitive type matching (resource types are lowercase)
• Navigate properties with properties.fieldName
• Use --first N to limit result count
• Use --subscriptions to scope to specific subscriptions
• Cross-reference orphaned resources with cost data from Cost Management API