Azure Blob Storage Skill

Manage and analyze Azure Blob Storage using az storage commands.

Discovery-First Rule

ALWAYS discover before acting. Never assume storage account names, container names, or access tiers.

# Discover storage accounts
az storage account list --output json \
  --query "[].{name:name, rg:resourceGroup, kind:kind, sku:sku.name, accessTier:accessTier, httpsOnly:enableHttpsTrafficOnly, location:location}"

Parallel Execution Requirement

ALL independent operations MUST run in parallel using background jobs (&) and wait.

for acct in $(echo "$accounts" | jq -c '.[]'); do
  {
    name=$(echo "$acct" | jq -r '.name')
    rg=$(echo "$acct" | jq -r '.rg')
    az storage account show --name "$name" --resource-group "$rg" --output json
  } &
done
wait

Helper Functions

# Get account key for operations (use --auth-mode login when possible)
get_connection_string() {
  local name="$1" rg="$2"
  az storage account show-connection-string --name "$name" --resource-group "$rg" --output tsv
}

# List containers in account
list_containers() {
  local name="$1"
  az storage container list --account-name "$name" --auth-mode login --output json \
    --query "[].{name:name, publicAccess:properties.publicAccess, leaseState:properties.leaseState, lastModified:properties.lastModified}"
}

# Get blob count and size summary
get_blob_stats() {
  local name="$1" container="$2"
  az storage blob list --account-name "$name" --container-name "$container" --auth-mode login \
    --output json --query "[].{name:name, tier:properties.blobTier, size:properties.contentLength, lastModified:properties.lastModified}" \
    --num-results 100
}

# Check lifecycle management policy
get_lifecycle_policy() {
  local name="$1" rg="$2"
  az storage account management-policy show --account-name "$name" --resource-group "$rg" --output json 2>/dev/null || echo '{"rules": []}'
}

Common Operations

1. Storage Account Overview

accounts=$(az storage account list --output json --query "[].{name:name, rg:resourceGroup}")
for acct in $(echo "$accounts" | jq -c '.[]'); do
  {
    name=$(echo "$acct" | jq -r '.name')
    rg=$(echo "$acct" | jq -r '.rg')
    az storage account show --name "$name" --resource-group "$rg" --output json \
      --query "{name:name, sku:sku.name, kind:kind, accessTier:accessTier, httpsOnly:enableHttpsTrafficOnly, minTlsVersion:minimumTlsVersion, allowBlobPublicAccess:allowBlobPublicAccess, networkRules:networkRuleSet.defaultAction}"
  } &
done
wait

2. Container Analysis

# List containers with access levels
az storage container list --account-name "$ACCT" --auth-mode login --output json \
  --query "[].{name:name, publicAccess:properties.publicAccess, leaseState:properties.leaseState, hasImmutability:properties.hasImmutabilityPolicy, hasLegalHold:properties.hasLegalHold}"

3. Access Tier Optimization

# Check blob tier distribution
az storage blob list --account-name "$ACCT" --container-name "$CONTAINER" --auth-mode login \
  --output json --query "[].properties.blobTier" | jq 'group_by(.) | map({tier: .[0], count: length})'

# Check storage capacity metrics
resource_id=$(az storage account show --name "$ACCT" --resource-group "$RG" --query "id" -o tsv)
az monitor metrics list --resource "${resource_id}/blobServices/default" \
  --metric "BlobCapacity" "BlobCount" --interval PT1H --aggregation Average \
  --dimension "BlobType" "Tier" --output json

4. Lifecycle Management

# Show lifecycle rules
az storage account management-policy show --account-name "$ACCT" --resource-group "$RG" --output json \
  --query "policy.rules[].{name:name, enabled:enabled, type:type, blobTypes:definition.filters.blobTypes, tierToCool:definition.actions.baseBlob.tierToCool.daysAfterModificationGreaterThan, tierToArchive:definition.actions.baseBlob.tierToArchive.daysAfterModificationGreaterThan, delete:definition.actions.baseBlob.delete.daysAfterModificationGreaterThan}"

5. Replication and Redundancy

az storage account show --name "$ACCT" --resource-group "$RG" --output json \
  --query "{sku:sku.name, kind:kind, geoReplicationStats:geoReplicationStats, secondaryLocation:secondaryLocation, secondaryEndpoints:secondaryEndpoints, blobRestoreStatus:blobRestoreStatus}"

# Check blob versioning and soft delete
az storage account blob-service-properties show --account-name "$ACCT" --resource-group "$RG" --output json \
  --query "{deleteRetention:deleteRetentionPolicy, containerDeleteRetention:containerDeleteRetentionPolicy, isVersioningEnabled:isVersioningEnabled, changeFeed:changeFeed}"

Output Format

Present results as a structured report:

Azure Blob Storage Report
═════════════════════════
Resources discovered: [count]

Resource       Status    Key Metric    Issues
──────────────────────────────────────────────
[name]         [ok/warn] [value]       [findings]

Summary: [total] resources | [ok] healthy | [warn] warnings | [crit] critical
Action Items: [list of prioritized findings]

Target ≤50 lines of output. Use tables for multi-resource comparisons.

Anti-Hallucination Rules

1. NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
2. NEVER fabricate metric names or dimensions — verify against the service documentation or --help output.
3. NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
4. ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
5. ALWAYS handle empty results gracefully — an empty response is valid data, not an error to retry.

Counter-Rationalizations

Shortcut	Counter	Why
"I'll skip discovery and check known resources"	Always run Phase 1 discovery first	Resource names change, new resources appear — assumed names cause errors
"The user only asked for a quick check"	Follow the full discovery → analysis flow	Quick checks miss critical issues; structured analysis catches silent failures
"Default configuration is probably fine"	Audit configuration explicitly	Defaults often leave logging, security, and optimization features disabled
"Metrics aren't needed for this"	Always check relevant metrics when available	API/CLI responses show current state; metrics reveal trends and intermittent issues
"I don't have access to that"	Try the command and report the actual error	Assumed permission failures prevent useful investigation; actual errors are informative

Common Pitfalls

1. Auth mode: Prefer --auth-mode login over account keys. Key-based access may be disabled by policy.
2. Public access: allowBlobPublicAccess at account level overrides container settings. Check both layers.
3. Tier transition costs: Moving blobs from Archive to Hot incurs rehydration costs and takes hours. Check blob count before bulk operations.
4. Lifecycle policy scope: Rules apply to entire containers or prefix filters. Verify filter scope to avoid unintended deletions.
5. GRS read access: RA-GRS and RA-GZRS provide read access to secondary region but with potential staleness. Check geoReplicationStats.lastSyncTime.