azure-role-selector

Azure Role Selector

Recommend the most appropriate Azure RBAC roles following the principle of least privilege. Find minimal built-in roles or define custom roles when needed.

Adapted from github/awesome-copilot azure-role-selector skill.

When to Use

• When deploying resources that need RBAC assignments
• When configuring managed identity access between resources
• When setting up service principals for CI/CD pipelines
• During security analysis to verify correct role assignments
• When user asks "what role do I need for X?"

Procedure

1. Understand Required Permissions

Ask the user what actions they need to perform:

What permissions do you need? Examples:
- "Read and write blobs in a storage account"
- "Deploy code to a Function App"
- "Read secrets from Key Vault"
- "Manage SQL databases"
- "Full access to a resource group"

2. Search for Built-In Roles

Use Azure MCP documentation tools to find matching built-in roles:

# List relevant built-in roles
az role definition list \
  --query "[?contains(roleName, '{keyword}')].{Name:roleName, Description:description, Id:name}" \
  --output table

# Get detailed permissions for a role
az role definition list \
  --name "{role-name}" \
  --output json

Cross-reference with Microsoft Docs for the latest role definitions.

3. Recommend Least-Privilege Role

Present the recommended role(s) in order of least privilege:

## Role Recommendation

**Desired:** Read and write blobs in storage account starnwkdhk

### Recommended Role (Least Privilege)
| Property | Value |
|----------|-------|
| **Role** | Storage Blob Data Contributor |
| **ID** | ba92f5b4-2d11-453d-a403-e96b0029c9fe |
| **Scope** | Storage Account level |
| **Permissions** | Read, write, delete blobs and containers |

### Alternatives (More Permissive)
| Role | Extra Permissions | Use When |
|------|-------------------|----------|
| Storage Account Contributor | Full account management | Need to manage account settings too |
| Contributor | Full resource management | Need broad access (not recommended) |

### ⚠️ Avoid These (Over-Privileged)
- **Owner** — Grants RBAC management, not needed for data access
- **Contributor** at subscription level — Too broad for storage-only needs

4. Generate Assignment Commands

Provide ready-to-use commands:

Azure CLI:

# Assign role to managed identity
az role assignment create \
  --assignee {principal-id} \
  --role "Storage Blob Data Contributor" \
  --scope /subscriptions/{sub-id}/resourceGroups/{rg}/providers/Microsoft.Storage/storageAccounts/{name}

# Assign role to service principal
az role assignment create \
  --assignee {app-id} \
  --role "Storage Blob Data Contributor" \
  --scope {resource-id}

ARM Template (for inclusion in deployment):

{
  "type": "Microsoft.Authorization/roleAssignments",
  "apiVersion": "2022-04-01",
  "name": "[guid(resourceId('Microsoft.Storage/storageAccounts', '{name}'), '{principal-id}', 'ba92f5b4-2d11-453d-a403-e96b0029c9fe')]",
  "scope": "[resourceId('Microsoft.Storage/storageAccounts', '{name}')]",
  "properties": {
    "roleDefinitionId": "[subscriptionResourceId('Microsoft.Authorization/roleDefinitions', 'ba92f5b4-2d11-453d-a403-e96b0029c9fe')]",
    "principalId": "{principal-id}",
    "principalType": "ServicePrincipal"
  }
}

5. Custom Role (If No Built-In Matches)

If no built-in role matches the exact permissions needed:

# Create custom role definition
az role definition create --role-definition '{
  "Name": "Custom Storage Reader Writer",
  "Description": "Can read and write blobs but not delete",
  "Actions": [
    "Microsoft.Storage/storageAccounts/blobServices/containers/read",
    "Microsoft.Storage/storageAccounts/blobServices/containers/blobs/read",
    "Microsoft.Storage/storageAccounts/blobServices/containers/blobs/write"
  ],
  "NotActions": [],
  "DataActions": [
    "Microsoft.Storage/storageAccounts/blobServices/containers/blobs/read",
    "Microsoft.Storage/storageAccounts/blobServices/containers/blobs/write"
  ],
  "NotDataActions": [],
  "AssignableScopes": ["/subscriptions/{sub-id}"]
}'

Common Role Mappings

Resource	Action	Recommended Role
Storage	Read/write blobs	Storage Blob Data Contributor
Storage	Read blobs only	Storage Blob Data Reader
Key Vault	Read secrets	Key Vault Secrets User
Key Vault	Manage secrets	Key Vault Secrets Officer
SQL Database	Read data	SQL DB Contributor
Function App	Deploy code	Website Contributor
App Service	Deploy code	Website Contributor
Cosmos DB	Read/write data	Cosmos DB Account Reader Role
Resource Group	Full management	Contributor (scoped to RG)
Monitoring	Read metrics	Monitoring Reader

Integration with Git-Ape

When the template generator creates resources with managed identities, invoke this skill to:

1. Identify what roles the managed identity needs
2. Add role assignment resources to the ARM template
3. Follow least-privilege principle automatically