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AWS Lambda

AWS LabsOfficialPublished by AWS Labs

  • Skill
  • Tool integration
  • Cloud and DevOps
  • Apache-2.0
  • Low risk
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From the author

Design, build, deploy, test, and debug serverless applications with AWS Lambda. Triggers on phrases like: Lambda function, event source, serverless application, API Gateway, EventBridge, Step Functions, serverless API, event-driven architecture, Lambda trigger. For deploying non-serverless apps to AWS, use deploy-on-aws plugin instead.
— the description by AWS Labs

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides comprehensive support for developing serverless applications on AWS. It integrates with the AWS Serverless MCP Server to assist with project initialization, infrastructure-as-code (IaC) generation, deployment, and debugging. It covers event-driven architectures, web application deployment via Lambda Web Adapter, and performance optimization, while enforcing best practices for security, idempotency, and observability.

What it does

  • Initializes and builds serverless projects using SAM CLI or CDK.
  • Configures event source mappings for services like DynamoDB, SQS, and Kinesis.
  • Deploys full-stack web applications using the Lambda Web Adapter.
  • Implements event-driven architectures with EventBridge and schema management.
  • Provides troubleshooting guidance for common deployment and runtime errors.
  • Enforces security best practices including least-privilege IAM and secret management.

When to use it

  • When starting a new serverless project on AWS.
  • When configuring event-driven triggers for Lambda functions.
  • When deploying web APIs or full-stack applications to AWS Lambda.
  • When optimizing Lambda performance, cost, or cold-start times.
  • When debugging deployment failures or runtime errors in serverless stacks.

Advantages

  • Automated validation of IaC templates via SAM CLI integration.
  • Built-in support for AWS Lambda Powertools for logging and idempotency.
  • Clear guidance on choosing between choreography and orchestration patterns.
  • Comprehensive troubleshooting and limit references for rapid debugging.
  • Standardized project setup using industry-recognized frameworks.

Usage examples

“Create a new serverless API project using TypeScript and CDK.”
The agent will initialize a new project structure, generate the necessary CDK constructs for an API Gateway and Lambda function, and set up the project configuration.
“How do I configure my Lambda to process messages from an SQS queue?”
The agent will provide the configuration steps for an Event Source Mapping, including best practices for batch sizes and partial failure handling.
“My Lambda function is failing with a timeout error, how can I debug it?”
The agent will guide you through checking CloudWatch logs, reviewing memory settings, and potentially using X-Ray tracing to identify the bottleneck.

Install

  1. Download the skill as a ZIP:

    https://autogineer.com/agent-skills/awslabs/aws-lambda/download

  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip aws-lambda.zip -d .agents/skills

Documentation by AWS Labs

AWS Lambda Serverless Development

Design, build, deploy, and debug serverless applications with AWS serverless services. This skill provides access to serverless development guidance through the AWS Serverless MCP Server, helping you to build production-ready serverless applications with best practices built-in.

Use SAM CLI for project initialization and deployment, Lambda Web Adapter for web applications, or Event Source Mappings for event-driven architectures. AWS handles infrastructure provisioning, scaling, and monitoring automatically.

Key capabilities:

  • SAM CLI Integration: Initialize, build, deploy, and test serverless applications

  • Web Application Deployment: Deploy full-stack applications with Lambda Web Adapter

  • Event Source Mappings: Configure Lambda triggers for DynamoDB, Kinesis, SQS, Kafka

  • Lambda durable functions: Resilient multi-step applications with checkpointing — see the durable-functions skill for guidance

  • Lambda Managed Instances: Run Lambda on dedicated EC2 instances with managed lifecycle — see the managed-instances skill for evaluation, configuration, and migration guidance

  • Schema Management: Type-safe EventBridge integration with schema registry

  • Observability: CloudWatch logs, metrics, and X-Ray tracing

  • Performance Optimization: Right-sizing, cost optimization, and troubleshooting

When to Load Reference Files

Load the appropriate reference file based on what the user is working on:

  • Getting started, what to build, project type decision, or working with existing projects -> see references/getting-started.md

  • SAM, CDK, deployment, IaC templates, CDK constructs, or CI/CD pipelines -> see the aws-serverless-deployment skill (separate skill in this plugin)

  • Web app deployment, Lambda Web Adapter, API endpoints, CORS, authentication, custom domains, or sam local start-api -> see references/web-app-deployment.md

  • Event sources, DynamoDB Streams, Kinesis, SQS, Kafka, S3 notifications, or SNS -> see references/event-sources.md

  • EventBridge, event bus, event patterns, event design, Pipes, or schema registry -> see references/event-driven-architecture.md

  • Durable functions, checkpointing, replay model, saga pattern, or long-running Lambda workflows -> see the durable-functions skill (separate skill in this plugin with full SDK reference, testing, and deployment guides)

  • Lambda Managed Instances, LMI, capacity providers, multi-concurrency, EC2-backed Lambda, cold start elimination, or Lambda cost optimization with Reserved Instances -> see the managed-instances skill (separate skill in this plugin for evaluation, configuration, and migration)

  • Orchestration, workflows, or Durable Functions vs Step Functions -> see references/orchestration-and-workflows.md

  • Step Functions, ASL, state machines, JSONata, Distributed Map, SDK integrations, TestState API, mocking service integrations, or state machine unit tests -> see the aws-step-functions skill for comprehensive guidance

  • Observability, logging, tracing, metrics, alarms, or dashboards -> see references/observability.md

  • Optimization, cold starts, memory tuning, cost, or streaming -> see references/optimization.md

  • Powertools, idempotency, feature flags, parameters, parser, batch processing, or data masking -> see references/powertools.md

  • Troubleshooting, errors, debugging, or deployment failures -> see references/troubleshooting.md

Best Practices

Project Setup

  • Do: Use sam_init or cdk init with an appropriate template for your use case

  • Do: Set global defaults for timeout, memory, runtime, and tracing (Globals in SAM, construct props in CDK)

  • Do: Use AWS Lambda Powertools for structured logging, tracing, metrics (EMF), idempotency, and batch processing — available for Python, TypeScript, Java, and .NET

  • Don't: Copy-paste templates from the internet without understanding the resource configuration

  • Don't: Use the same memory and timeout values for all functions regardless of workload

Security

  • Do: Follow least-privilege IAM policies scoped to specific resources and actions

  • Do: Use secure_esm_* tools to generate correct IAM policies for event source mappings

  • Do: Store secrets in AWS Secrets Manager or SSM Parameter Store, never in environment variables

  • Do: Use VPC endpoints instead of NAT Gateways for AWS service access when possible

  • Do: Enable Amazon GuardDuty Lambda Protection to monitor function network activity for threats (cryptocurrency mining, data exfiltration, C2 callbacks)

  • Don't: Use wildcard (*) resource ARNs or actions in IAM policies

  • Don't: Hardcode credentials or secrets in application code or templates

  • Don't: Store user data or sensitive information in module-level variables — execution environments can be reused across different callers

Idempotency

  • Do: Write idempotent function code — Lambda delivers events at least once, so duplicate invocations must be safe

  • Do: Use the AWS Lambda Powertools Idempotency utility (backed by DynamoDB) for critical operations

  • Do: Validate and deduplicate events at the start of the handler before performing side effects

  • Don't: Assume an event will only ever be processed once

For topic-specific best practices, see the dedicated guide files in the reference table above.

Lambda Limits Quick Reference

Limits that developers commonly hit:

ResourceLimit
Function timeout900 seconds (15 minutes)
Memory128 MB – 10,240 MB
1 vCPU equivalent1,769 MB memory
Synchronous payload (request + response)6 MB each
Async invocation payload1 MB
Streamed response200 MB
Deployment package (.zip, uncompressed)250 MB
Deployment package (.zip upload, compressed)50 MB
Container image10 GB
Layers per function5
Environment variables (aggregate)4 KB
/tmp ephemeral storage512 MB – 10,240 MB
Account concurrent executions (default)1,000 (requestable increase)
Burst scaling rate1,000 new executions per 10 seconds

Check Service Quotas for your account limits: aws lambda get-account-settings

Troubleshooting Quick Reference

ErrorCauseSolution
Build FailedMissing dependenciesRun sam_build with use_container: true
Stack is in ROLLBACK_COMPLETEPrevious deploy failedDelete stack with aws cloudformation delete-stack, redeploy
IteratorAge increasingStream consumer falling behindIncrease ParallelizationFactor and BatchSize. Use esm_optimize
EventBridge events silently droppedNo DLQ, retries exhaustedAdd RetryPolicy + DeadLetterConfig to rule target
Step Functions failing silentlyNo retry on Task stateAdd Retry with Lambda.ServiceException, Lambda.AWSLambdaException
Durable Function not resumingMissing IAM permissionsAdd lambda:CheckpointDurableExecution and lambda:GetDurableExecutionState — see durable-functions skill

For detailed troubleshooting, see references/troubleshooting.md.

Configuration

AWS CLI Setup

This skill requires that AWS credentials are configured on the host machine:

Verify access: Run aws sts get-caller-identity to confirm credentials are valid

SAM CLI Setup

  1. Install SAM CLI: Follow the SAM CLI installation guide

  2. Verify: Run sam --version

Container Runtime Setup

  1. Install a Docker compatible container runtime: Required for sam_local_invoke and container-based builds

  2. Verify: Use an appropriate command such as docker --version or finch --version

MCP Server Configuration

Write access is enabled by default. The plugin ships with --allow-write in .mcp.json, so the MCP server can create projects, generate IaC, and deploy on behalf of the user.

Access to sensitive data (like Lambda and API Gateway logs) is not enabled by default. To grant it, add --allow-sensitive-data-access to .mcp.json.

SAM Template Validation Hook

This plugin includes a PostToolUse hook that runs sam validate automatically after any edit to template.yaml or template.yml. If validation fails, the error is returned as a system message so you can fix it immediately. The hook requires SAM CLI and jq to be installed; if either is missing, validation is skipped with a system message. Users can disable it via /hooks.

Verify: Run jq --version

Language selection

Default: TypeScript

Override syntax:

  • "use Python" → Generate Python code

  • "use JavaScript" → Generate JavaScript code

When not specified, ALWAYS use TypeScript

IaC framework selection

Default: CDK

Override syntax:

  • "use CloudFormation" → Generate YAML templates

  • "use SAM" → Generate YAML templates

When not specified, ALWAYS use CDK

Serverless MCP Server Unavailable

  • Inform user: "AWS Serverless MCP not responding"

  • Ask: "Proceed without MCP support?"

  • DO NOT continue without user confirmation

Resources

Files

references/getting-started.md

Getting Started with AWS Serverless Development

Prerequisites

Verify these tools before proceeding:

aws --version                  # AWS CLI
aws sts get-caller-identity    # Credentials configured
sam --version                  # SAM CLI

Verify that any Docker-compatible container runtime is installed (Docker, Finch, Podman, etc.). Use the appropriate command for your runtime (e.g., finch --version).

If aws sts get-caller-identity fails, ask user to set up credentials. If using CDK instead of SAM, also run cdk --version — see cdk-project-setup.md.

What Are You Building?

REST/HTTP API

An API backend serving JSON over HTTPS — the most common serverless pattern.

Quick start:

  • Template: hello-world (single function + API Gateway) or quick-start-web (web framework)

  • Runtime: nodejs22.x or python3.12

  • Architecture: arm64

Read next:

  • sam-project-setup.md — project scaffolding, deployment workflow, handler examples, container image packaging for large dependencies

  • web-app-deployment.md — API endpoint selection (HTTP API vs REST API vs Function URL vs ALB), CORS, custom domains, authentication

Full-Stack Web Application

A frontend (React, Vue, Angular, Next.js) with a backend API, deployed together.

Quick start:

  • Template: quick-start-web

  • Use deploy_webapp with deployment_type: "fullstack" for S3 + CloudFront + Lambda + API Gateway

Read next:

Event Processor

A Lambda function triggered by a queue, stream, or database change — SQS, Kinesis, DynamoDB Streams, Kafka, or DocumentDB.

Quick start:

  • Template: hello-world (then add an event source in template.yaml)

  • Use esm_guidance to get the correct ESM configuration for your source

  • Use secure_esm_* tools to generate least-privilege IAM policies

Read next:

File/Object Processor

A Lambda function triggered when files are uploaded to or deleted from S3 — image processing, file validation, data import, thumbnail generation.

Quick start:

  • Template: hello-world (then add an S3 event in template.yaml)

  • Use prefix/suffix filters to limit triggers to specific paths or file types

Read next:

  • event-sources.md — S3 event notification configuration and recursive trigger prevention

Notification Fan-Out

One event triggers multiple independent consumers — order notifications, alert distribution, cross-service communication.

Quick start:

  • Create an SNS topic and subscribe multiple Lambda functions

  • Use filter policies to route subsets of messages to specific consumers

Read next:

Event-Driven Architecture

Multiple services communicating through events on EventBridge — decoupled, independently deployable.

Quick start:

  • Create a custom event bus (never use the default bus for application events)

  • Define event schemas with metadata envelope for idempotency and tracing

  • Use search_schema and describe_schema for schema discovery

Read next:

Multi-Step Workflow or AI Pipeline

A workflow with sequential steps, parallel execution, human approval, or checkpointing — order processing, document pipelines, agentic AI.

Quick start:

  • Python 3.11+ or Node.js 22+: Use Lambda durable functions for workflows expressed as code — see the durable-functions skill for comprehensive guidance

  • Any runtime: Use Step Functions for visual orchestration with 200+ AWS service integrations

  • High-throughput, short-lived: Use Step Functions Express (100k+ exec/sec)

Read next:

Scheduled Job

A Lambda function triggered on a cron schedule — reports, cleanup tasks, data sync.

Add a Schedule event to your function in template.yaml:

MyScheduledFunction:
  Type: AWS::Serverless::Function
  Properties:
    Handler: src/handlers/report.handler
    Events:
      DailyReport:
        Type: Schedule
        Properties:
          Schedule: cron(0 8 * * ? *)   # 8:00 AM UTC daily
          Enabled: true

Read next:

  • sam-project-setup.md — project setup and deployment workflow

Working with Existing Projects

When joining or modifying an existing SAM project:

  1. Look for template.yaml (or template.yml) at the project root

  2. Check samconfig.toml for deployment configuration and environment profiles

  3. Run sam_build to verify the project builds

  4. Use sam_logs and get_metrics to understand current behavior before making changes

For CDK projects, look for cdk.json and run cdk synth to verify synthesis. See cdk-project-setup.md.

Requirements and compatibility

Written for: Claude Code

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Claude Code frontmatter, Needs an MCP server

Security

What our scanner noticed· Low risk

  • Instructions that use the network

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Published by
AWS Labs
Publisher
AWS Labs (Official)
Source
awslabs/agent-plugins · plugins/aws-serverless/skills/aws-lambda · commit fbefb37
Licence
Apache License 2.0 (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • NOTICE (added by AutoGineer from NOTICE)
  • ATTRIBUTION.md (written by AutoGineer)
Synced

AutoGineer is not affiliated with or endorsed by AWS Labs or AWS Labs.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download aws-lambda.zip