AWS Cost Analysis

AWS Cost Analysis

Query AWS Cost Explorer data to break down spending by service, identify trends, detect anomalies, and recommend cost optimization actions.

Instructions

Phase 1: Cost Breakdown

1. Fetch cost data using the AWS agent's Cost Explorer tools:
   • Total spend for the requested period (default: last 30 days)
   • Breakdown by AWS service (EC2, EKS, S3, RDS, Lambda, etc.)
   • Breakdown by account (if multi-account)
   • Daily/weekly cost trends
2. Calculate key metrics:
   • Month-over-month change (absolute and percentage)
   • Top 5 most expensive services
   • Top 5 fastest-growing services (by percentage increase)

Phase 2: Anomaly Detection

1. Identify cost anomalies:
   • Services with >20% cost increase vs. previous period
   • Sudden spikes in daily spend
   • New services that appeared this period
   • Unused resources still incurring charges
2. Flag potential waste:
   • Idle EC2 instances (low CPU utilization)
   • Unattached EBS volumes
   • Old snapshots and AMIs
   • Underutilized RDS instances
   • NAT Gateway data transfer costs

Phase 3: Optimization Recommendations

Provide actionable recommendations with estimated savings:

• Reserved Instances or Savings Plans opportunities
• Right-sizing overprovisioned resources
• Storage tier optimization (S3 lifecycle policies)
• Spot Instance candidates for non-critical workloads
• Cleanup of orphaned resources

Output Format

## AWS Cost Analysis Report
**Period**: Feb 1 - Feb 9, 2026 | **Total Spend**: $24,567.89

### Cost Trend
| Week | Spend | Change |
|------|-------|--------|
| Jan 27 - Feb 2 | $5,890 | baseline |
| Feb 3 - Feb 9 | $6,234 | +5.8% |

### Top 5 Services by Cost
| Service | Cost | % of Total | MoM Change |
|---------|------|------------|------------|
| Amazon EKS | $8,234 | 33.5% | +12% |
| Amazon EC2 | $6,789 | 27.6% | -3% |
| Amazon S3 | $3,456 | 14.1% | +2% |
| Amazon RDS | $2,345 | 9.5% | +0% |
| AWS Lambda | $1,234 | 5.0% | +45% |

### Anomalies Detected
1. **Lambda costs up 45%** - New function `data-pipeline-processor` deployed Feb 3
2. **EKS costs up 12%** - Node group scaled from 5 to 8 nodes

### Optimization Opportunities
| Recommendation | Estimated Monthly Savings |
|---------------|--------------------------|
| Right-size 3 oversized EC2 instances | $450/mo |
| Purchase EKS Savings Plan | $1,200/mo |
| Delete 12 unattached EBS volumes | $180/mo |
| **Total Potential Savings** | **$1,830/mo** |

Examples

• "Show me the AWS cost breakdown for the last month"
• "What are our top 5 most expensive AWS services?"
• "Are there any cost anomalies this month?"
• "How can we reduce our AWS spend?"
• "Compare this month's AWS costs to last month"

Guidelines

• Default to last 30 days if no time period is specified
• Always show both absolute costs and percentage of total
• Include month-over-month comparison for context
• Round costs to 2 decimal places for totals, whole dollars for individual services
• When costs exceed expectations, investigate the root cause before recommending action
• Be specific in optimization recommendations (name the resource, not just the category)
• Distinguish between one-time spikes and sustained cost increases