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aws-serverless

Builds, deploys, manages, debugs, configures, and optimizes serverless applications on AWS using Lambda, API Gateway, Step Functions, EventBridge, and SAM/CDK. Covers cold starts, CORS debugging, event source mappings, troubleshooting, concurrency, SnapStart, Powertools, function URLs, EventBridge Scheduler, Lambda layers, and production readiness. Triggers on mentions of Lambda, API Gateway, Step Functions, SAM templates, CDK serverless stacks, DynamoDB stream triggers, SQS event sources, cold starts, timeouts, 502/504 errors, throttling, concurrency, CORS, Powertools, or any event-driven architecture on AWS, even without the word "serverless." Does not apply to EC2, ECS/Fargate containers, or Amplify hosting.

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SKILL.md
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AWS Serverless

Domain expertise for building serverless applications on AWS: Lambda, API Gateway, Step Functions, EventBridge, event source mappings, concurrency, cold starts, deployment, and troubleshooting.

Works best with the AWS MCP server — run CLI commands, query CloudWatch, validate configs directly. All guidance also works with standard AWS CLI access.

Specialized skills — check these first

These cover capabilities and procedures the general references below do not. Several are specialized features or step-by-step tested procedures you would otherwise miss. Route to the matching skill before falling back to the references.

Advanced Lambda compute (easy to overlook)

Use this skillWhen the workload involves
aws-lambda-microvmsStrong tenant isolation, sandboxed/untrusted code execution (AI agent code sandboxes, REPLs, notebooks, CI runners), long-lived sessions, suspend/resume with preserved state, port-listening servers (gRPC, WebSocket, custom TCP), Firecracker microVMs, snapshot-resumable compute, up to 8-hour lifetimes
aws-lambda-durable-functionsDurable execution, checkpoint-and-replay, long-running multi-step workflows written as plain code (TS/Python/Java), automatic state persistence, saga pattern in code, human-in-the-loop callbacks, executions up to 1 year, context.step/context.wait/context.invoke, withDurableExecution, durable-execution-sdk
aws-lambda-managed-instancesLambda Managed Instances (LMI), capacity providers, EC2-backed Lambda, steady high-volume traffic (50M+ req/mo) wanting Savings Plans / Reserved Instance pricing, PerExecutionEnvironmentMaxConcurrency, CapacityProviderConfig, multi-concurrent execution environments

Step-by-step task procedures (tested CLI SOPs)

Use this skillFor the task
connecting-lambda-to-api-gatewayWire an existing Lambda to a new REST/HTTP API: proxy integration, permissions, CORS, throttling, access logging, deployment
connecting-lambda-to-dynamodbConnect Lambda to DynamoDB: IAM execution role, read/write permissions, stream event source mapping
creating-api-gateway-stageCreate an API Gateway stage with CloudWatch logging, X-Ray tracing, throttling, WAF association, and authorization
deploying-custom-domain-rest-apiDeploy a Regional REST API with custom domain: ACM cert, Lambda backend, request authorizer, base path mapping, Route 53 DNS
debugging-lambda-timeoutsSystematically diagnose a timing-out Lambda: config, CloudWatch logs/metrics, VPC, cold starts, memory, downstream calls
processing-s3-uploads-with-step-functionsDeploy an event-driven workflow: S3 upload → EventBridge → Step Functions → Lambda (small files) or Fargate (large files), with VPC/ECR/ECS/IAM

Routing (general references in this skill)

User needRead
Building a new serverless app — pattern selectionarchitecture.md
Lambda config, cold starts, SnapStart, memory, VPC, layers, Function URLslambda.md
Concurrency (reserved, provisioned, ESM controls)concurrency.md
Event sources (SQS, DynamoDB Streams, SNS, Kinesis), filtering, batch failuresevent-sources.md
Step Functions, EventBridge rules/pipes/schedulerorchestration.md
API Gateway quotas, authorizers, WebSocketapi-gateway.md
SAM/CDK resource types and fast iterationdeployment.md
Production readiness, observability, anti-patternsproduction.md
Debugging an error (exact string → cause → fix)troubleshooting.md
Powertools handler templatepowertools-handler.py

Note: Reference files contain specific runtime versions, quotas, and feature matrices that change. When precision matters (production, runtime choice, quotas), confirm against current AWS documentation. The references focus on values and gotchas that are easy to get wrong — not on basics.

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aws/agent-toolkit-for-aws
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