> ## Documentation Index
> Fetch the complete documentation index at: https://docs.opsbeacon.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Cost Drivers & Root Cause Analysis

> Find out exactly what changed in your AWS bill and why.

## What it shows

When your AWS spend increases, Beacon traces the change down to the specific service, usage type, region, and resource level — so you know what to investigate.

## How to use it

```
@Beacon what's driving my cost increase this month?
@Beacon why did EC2 spend go up 40% last week?
@Beacon what's the most expensive thing in my account right now?
```

## Output format

Beacon returns:

* The primary cost driver (service + usage type)
* The change in absolute dollars and percentage
* The region and account where the change occurred
* Where possible, the specific resource type or operation responsible

## Limitations

Root cause analysis works at the service and usage-type level. Beacon cannot currently identify specific EC2 instance IDs or Lambda function names as cost drivers — that level of detail requires AWS Cost Allocation Tags or AWS Cost Anomaly Detection with resource-level tagging.


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