Bedrock and a hard place: Claude adventure leaves AWS user staring down $30K invoice

"Our reader managed to run up Bedrock charges totaling $30,141.33 in April 2026, despite using AWS Cost Anomaly Detection (CAD) to avoid any nasty surprises. Thirty-three days before our reader's first use of Bedrock, the threshold in CAD was set to "Absolute ≥ $100 AND Relative ≥ 40%" so alerts should have fired if things got too spendy."

"As for which services to monitor, our reader chose "AWS Services," which Amazon says "tracks all AWS services automatically." Except it apparently doesn't, at least not in the way our reader expected. The problem is that AWS Marketplace isn't supported by CAD, so costs incurred wouldn't trigger an alert. And how are Anthropic Claude models billed? Through the AWS Marketplace."

"After burning through our reader's AWS Activate credits (totaling $8,026.54 in this case), Amazon started charging for model inference on the Bedrock Marketplace, racking up $30,141.33, plus another $675.07 in AWS infrastructure charges, without a peep from the CAD service. "The credits masking made it worse," our reader told us."

""AWS Activate credits did cover the first ~$8k of charges, which meant the Marketplace billing was silently working for weeks before the credits ran out. There was no notification when credits were exhausted - the charges simply started accumulating as invoiced amounts." The first warning that things were mounting up came in the form of a surprisingly large invoice."

AWS Cost Anomaly Detection can miss spend that originates from AWS Marketplace. A user ran Anthropic Claude Opus on Amazon Bedrock and incurred $30,141.33 in April 2026 charges even though CAD thresholds were configured to trigger alerts. The user selected “AWS Services,” which is described as tracking all AWS services automatically, but AWS Marketplace was not supported by CAD. Bedrock Claude model billing occurs through the AWS Marketplace, so Marketplace costs did not trigger alerts. AWS Activate credits masked the issue for weeks, with no notification when credits were exhausted, and charges began accumulating as invoiced amounts. The first indication was a large invoice, followed by additional infrastructure charges.

Read at theregister