AWS Cdk Development

AWS CDK Development

This skill provides comprehensive guidance for developing AWS infrastructure using the Cloud Development Kit (CDK), with integrated MCP servers for accessing latest AWS knowledge and CDK utilities.

Dependency: This skill requires AWS MCP tools. If MCP tools are unavailable, run /aws-mcp-setup to configure them first.

AWS Documentation Requirement

CRITICAL: Always verify using AWS MCP tools (if available):

• mcp__aws-mcp__aws___search_documentation or mcp__awsdocs__aws___search_documentation — Search AWS docs
• mcp__aws-mcp__aws___read_documentation or mcp__awsdocs__aws___read_documentation — Read specific pages
• mcp__aws-mcp__aws___get_regional_availability — Check service availability

If AWS MCP tools are unavailable, run /aws-mcp-setup to configure them. Choose the option that fits your environment:

• Has uvx + AWS credentials → Full AWS MCP Server
• No Python/credentials → AWS Documentation MCP (no auth)

Integrated MCP Servers

AWS CDK MCP Server

If awslabs.aws-iac-mcp-server is configured (mcp__awslabs.aws-iac-mcp-server__*), use it for CDK-specific guidance:

• Get CDK construct recommendations
• Retrieve CDK best practices (cdk_best_practices)
• Search CDK samples (search_cdk_samples_and_constructs)
• Search CDK documentation (search_cdk_documentation)

When to Use This Skill

Use this skill when:

• Creating new CDK stacks or constructs
• Refactoring existing CDK infrastructure
• Implementing Lambda functions within CDK
• Following AWS CDK best practices
• Validating CDK stack configurations before deployment
• Verifying AWS service capabilities and regional availability

Core CDK Principles

Resource Naming

CRITICAL: Do NOT explicitly specify resource names when they are optional in CDK constructs.

Why: CDK-generated names enable:

• Reusable patterns: Deploy the same construct/pattern multiple times without conflicts
• Parallel deployments: Multiple stacks can deploy simultaneously in the same region
• Stack isolation: Each stack gets uniquely identified resources automatically

// ❌ BAD - Explicit naming prevents reusability and parallel deployments
new lambda.Function(this, 'MyFunction', {
  functionName: 'my-lambda', // Avoid this
});

// ✅ GOOD - Let CDK generate unique names
new lambda.Function(this, 'MyFunction', {
  // No functionName specified - CDK generates: StackName-MyFunctionXXXXXX
});

Security Note: For different environments (dev, staging, prod), use separate AWS accounts rather than relying on resource naming within a single account.

Lambda Function Development

TypeScript/JavaScript: Use @aws-cdk/aws-lambda-nodejs

import { NodejsFunction } from 'aws-cdk-lib/aws-lambda-nodejs';

new NodejsFunction(this, 'MyFunction', {
  entry: 'lambda/handler.ts',
  handler: 'handler',
  // Automatically handles bundling, dependencies, and transpilation
});

Python: Use @aws-cdk/aws-lambda-python

import { PythonFunction } from '@aws-cdk/aws-lambda-python-alpha';

new PythonFunction(this, 'MyFunction', {
  entry: 'lambda',
  index: 'handler.py',
  handler: 'handler',
  // Automatically handles dependencies and packaging
});

Pre-Deployment Validation

Use a multi-layer validation strategy:

Layer 1: Real-Time IDE Feedback

Install cdk-nag for synthesis-time validation:

npm install --save-dev cdk-nag

Add to your CDK app:

import { Aspects } from 'aws-cdk-lib';
import { AwsSolutionsChecks } from 'cdk-nag';

const app = new App();
Aspects.of(app).add(new AwsSolutionsChecks());

Layer 2: Synthesis-Time Validation (Required)

cdk synth # cdk-nag runs automatically via Aspects

Suppress legitimate exceptions with documented reasons:

import { NagSuppressions } from 'cdk-nag';

NagSuppressions.addResourceSuppressions(resource, [
  {
    id: 'AwsSolutions-L1',
    reason: 'Lambda@Edge requires specific runtime for CloudFront compatibility'
  }
]);

Layer 3: Pre-Commit Safety Net

npm run build   # Ensure compilation succeeds
npm test        # Run unit and integration tests
cdk synth       # Validate synthesis

Workflow Guidelines

Development Workflow

1. Design: Plan infrastructure resources and relationships
2. Verify AWS Services: Use AWS Documentation MCP to confirm service availability
3. Implement: Write CDK constructs following best practices
4. Validate: Run pre-deployment checks
5. Synthesize: cdk synth
6. Review: Examine synthesized templates
7. Deploy: cdk deploy
8. Verify: Confirm resources are created correctly

Stack Organization

• Use nested stacks for complex applications
• Separate concerns into logical construct boundaries
• Export values that other stacks may need
• Use CDK context for environment-specific configuration

Testing Strategy

• Unit test individual constructs
• Integration test stack synthesis
• Snapshot test CloudFormation templates
• Validate resource properties and relationships

CDK Patterns Reference

For detailed CDK patterns, anti-patterns, and architectural guidance, refer to:

File: .cursor/skills/aws-cdk-development/references/cdk-patterns.md

This reference includes:

• Common CDK patterns and their use cases
• Anti-patterns to avoid
• Security best practices
• Cost optimization strategies
• Performance considerations

Additional Resources

• Validation Script: .cursor/skills/aws-cdk-development/scripts/validate-stack.sh
• CDK Patterns: .cursor/skills/aws-cdk-development/references/cdk-patterns.md

GitHub Actions Integration

When GitHub Actions workflow files exist in the repository, ensure all checks defined in .github/workflows/ pass before committing. Use the github-actions-validator subagent to validate and update these workflows.