aws-cloudformation-lambda
AWS CloudFormation patterns for Lambda functions, layers, event sources, and integrations. Use when creating Lambda functions with CloudFormation, configuring API Gateway, Step Functions, EventBridge, SQS, SNS triggers, and implementing template structure with Parameters, Outputs, Mappings, Conditions, cross-stack references, and best practices for cold start optimization.
Install with Tessl CLI
npx tessl i github:giuseppe-trisciuoglio/developer-kit --skill aws-cloudformation-lambda83
Does it follow best practices?
If you maintain this skill, you can automatically optimize it using the tessl CLI to improve its score:
npx tessl skill review --optimize ./path/to/skillValidation for skill structure
Discovery
100%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This is a strong skill description that excels across all dimensions. It provides comprehensive coverage of specific capabilities (Lambda, layers, event sources, various AWS integrations), includes explicit 'Use when' guidance with natural trigger terms, and carves out a distinct niche at the intersection of CloudFormation and Lambda patterns. The description uses proper third-person voice throughout.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions: 'Lambda functions, layers, event sources, integrations', 'configuring API Gateway, Step Functions, EventBridge, SQS, SNS triggers', and 'template structure with Parameters, Outputs, Mappings, Conditions, cross-stack references'. | 3 / 3 |
Completeness | Clearly answers both what (AWS CloudFormation patterns for Lambda and related services) and when ('Use when creating Lambda functions with CloudFormation, configuring API Gateway...'). Has explicit 'Use when' clause with specific trigger scenarios. | 3 / 3 |
Trigger Term Quality | Excellent coverage of natural terms users would say: 'CloudFormation', 'Lambda', 'API Gateway', 'Step Functions', 'EventBridge', 'SQS', 'SNS', 'triggers', 'Parameters', 'Outputs', 'cold start' - all common AWS terminology users naturally use. | 3 / 3 |
Distinctiveness Conflict Risk | Very specific niche combining AWS CloudFormation with Lambda-specific patterns. The combination of CloudFormation + Lambda + specific AWS services creates a distinct trigger profile unlikely to conflict with general AWS or general IaC skills. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
72%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This is a comprehensive CloudFormation Lambda skill with excellent actionability through complete, executable YAML templates and CLI commands. However, it suffers from verbosity—explaining concepts Claude already knows and including redundant descriptions. The workflow clarity could be improved by adding explicit validation checkpoints for stack deployments and error recovery patterns.
Suggestions
Remove explanatory prose that describes what AWS services do (e.g., 'Stack policies protect stack resources from unintentional updates') and keep only the actionable templates and commands
Add a deployment workflow section with explicit validation steps: create change set → review → validate template with cfn-lint → execute → verify stack status
Consolidate similar template patterns (e.g., the multiple Lambda function definitions) into a single annotated example with inline comments for variations
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill is comprehensive but overly verbose in places. Many sections include explanatory comments and descriptions that Claude already knows (e.g., explaining what termination protection does, what drift detection is). The template examples are thorough but could be more condensed. | 2 / 3 |
Actionability | Excellent actionability with fully executable CloudFormation YAML templates throughout. Code is copy-paste ready with proper syntax, includes CLI commands for stack management, and provides complete resource definitions with all required properties. | 3 / 3 |
Workflow Clarity | While individual sections are clear, the overall workflow for creating Lambda infrastructure lacks explicit validation checkpoints. The change set workflow section is well-sequenced, but other multi-step processes (like deploying a full stack) don't include verification steps or error recovery guidance. | 2 / 3 |
Progressive Disclosure | Good structure with clear section headers, a logical progression from basic to advanced topics, and appropriate references to external files (REFERENCE.md, EXAMPLES.md) for detailed content. The overview provides quick orientation before diving into specifics. | 3 / 3 |
Total | 10 / 12 Passed |
Validation
62%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 10 / 16 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
skill_md_line_count | SKILL.md is long (1538 lines); consider splitting into references/ and linking | Warning |
allowed_tools_field | 'allowed-tools' contains unusual tool name(s) | Warning |
metadata_version | 'metadata' field is not a dictionary | Warning |
license_field | 'license' field is missing | Warning |
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
body_steps | No step-by-step structure detected (no ordered list); consider adding a simple workflow | Warning |
Total | 10 / 16 Passed | |
- Reviewed
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