Amazon Web Services · billing · fg-0183
Setting reserved concurrency fails with decreases account's UnreservedConcurrentExecution below its minimum value on a new AWS account
InvalidParameterValueException: Specified ReservedConcurrentExecutions for function decreases account's UnreservedConcurrentExecution below its minimum value
Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100
Cause
New accounts start with a reduced Lambda concurrency quota that AWS raises over time with usage. Reserving concurrency for one function must leave a minimum unreserved pool, which a small quota cannot cover.
Fix
Remove or lower reserved concurrency until the quota is raised, and request a Concurrent executions increase in Service Quotas.
Apply
aws service-quotas get-service-quota --service-code lambda --quota-code L-B99A9384 aws service-quotas request-service-quota-increase --service-code lambda --quota-code L-B99A9384 --desired-value 1000
Affects: New AWS accounts with the reduced default Lambda concurrency quota; any Region
Sources
- https://docs.aws.amazon.com/lambda/latest/dg/gettingstarted-limits.html
- https://docs.aws.amazon.com/lambda/latest/dg/troubleshooting-deployment.html
Have your agent know this before it fails
claude mcp add --transport http footgun https://getfootgun.com/api/mcp