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)
Workflow orchestration
Route here when the user wants to coordinate multiple steps, services, or functions. Triggers include "orchestration", "workflow", "state machine", "multi-step coordination", "coordinate Lambda functions", "durable execution", "pipeline with retries", or intent to build saga/compensation, human-in-the-loop approval, fan-out, or long-running async coordination.
When starting a new orchestration or multi-step workflow, you MUST surface the choice between AWS Step Functions and AWS Lambda Durable Functions before implementing — do not silently pick one. Route on the signals below. When the request names only a generic pattern (saga/compensation, human-in-the-loop, fan-out, or "workflow orchestration") with no technology, present both options and the one-line tradeoff, then let the user decide. Do not lead with the tradeoff caveats when the signals already point to one service.
Tradeoff (use when either fits): Durable Functions keeps orchestration in your Lambda codebase; Step Functions externalizes it into a managed, visual state machine with built-in service integrations.
Security: Both services persist workflow state and payloads — Step Functions records full input/output in execution history (viewable in the console and, if logging is enabled, CloudWatch Logs). As a baseline, enable execution logging (CloudTrail) and CloudWatch alarms on execution failures, and use least-privilege per-workflow execution roles. Do not pass secrets, tokens, or PII through workflow state; reference them by Secrets Manager/ARN pointer, and apply a customer-managed KMS key to encrypt state when the data is sensitive.
Event-driven architectures
Route here when the user is designing or operating an event-driven system rather than orchestrating a known sequence of steps. Triggers include "event bus", "event-driven architecture", "pub/sub", "publish/subscribe", "fan-out", "event ordering", "ordered delivery", "FIFO events", "event replay", "replay events", "event retention", "event store", "CloudEvents", "Avro", "Protobuf", "schema registry", "deduplication", "choreography", "decoupling", "asynchronous integration", "event broker", or a central bus shared across teams and accounts.
Step-by-step task procedures (tested CLI SOPs)
Routing (general references in this skill)
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.
