Conciseness

The body is dense and high-signal — anti-pattern tables, decision matrices, and specific thresholds with no explanations of concepts Claude already knows. It falls short of 5 because time-sensitive dates are embedded in main sections rather than a deprecated/old-patterns section ("INIT is billed since August 2025"; the SnapStart matrix with Nov 2021/Oct 2024 dates), and the 3-point Layers answer plus the attribution quote add tokens that could be trimmed or pushed to the reference.

Actionability

Guidance is concrete and directly executable throughout: exact config (`logging_config { log_format = "JSON" }`), specific ratios ("set it to 6× Lambda timeout"), hard limits ("limit of 5 layers per function"), "HTTP API ~70% cheaper", and a named tool with setup pointer (awslabs.aws-pricing-mcp-server README). As an instruction-only skill the absence of code blocks is not penalized because the directives are specific and actionable.

Workflow Clarity

This is an advisory skill whose single workflow — identify the topic, load the right reference — is unambiguous: the Reference Loading Strategy gives a numbered 5-way mapping from question type to file, reinforced by the Quick Reference table. There are no destructive or batch operations, so no validation checkpoints are required and the simple-skill exception applies.

Progressive Disclosure

SKILL.md is a genuine overview: a Quick Reference table pairing each reference file with a key insight, plus an explicit loading strategy. All five referenced files (api-gateway, event-driven, lambda-patterns, lambda-powertools, monitoring) exist, are one level deep, and only cross-link peer-to-peer — no nested reference chains. Inline content (anti-patterns, decision tables) is appropriately the high-value summary material.

Specificity

Names concrete actions ("designing, debugging or reviewing") and comprehensively enumerates specific capabilities: "cold starts and INIT billing, Lambda Layers, packaging and shared dependencies, deployment package size, concurrency, runtime choice, Powertools, logging and tracing, alarms, retries and DLQs, payload limits" plus three explicit either/or decisions (HTTP vs REST API, Lambda vs Step Functions, Lambda vs ECS). Coverage is comprehensive rather than having minor gaps, so it fits the 5 anchor better than 4.

Completeness

Explicitly answers 'when' with a leading "Use when designing, debugging or reviewing..." clause containing concrete trigger phrases, and the 'what' is explicit in the enumerated topic scope. It even adds a negative boundary ("Not for creating a new service from a template"), making both halves maximally explicit — the 4 anchor's caveat ('when' could be more specific) does not apply.

Trigger Term Quality

Uses exactly the natural terms a user would say: service names and abbreviations ("Lambda, API Gateway, SQS, SNS, EventBridge or Step Functions", "ECS") plus feature vocabulary ("cold starts", "Lambda Layers", "DLQs", "Powertools", "payload limits"). Both full names and common short forms are present, matching the comprehensive-synonyms anchor; nothing a user would plausibly type is missing.

Distinctiveness Conflict Risk

Clear niche (AWS serverless) with distinct, service-specific triggers and an explicit disambiguation against the sibling skill "creating-aws-projects". Minimal conflict risk: the named services and topics would not naturally route to a different skill.