Conciseness

The command reference is efficient, but several sections are padding: "Integration with Kiro CLI", "Example Prompts" (prompts Claude doesn't need), "Best Practices" listing advice Claude already knows ("Always test in non-production first", "Document all cost optimization actions"), and "Safety Notes" largely duplicating the "Analysis and change boundary" section. This matches "Mostly efficient but includes some unnecessary explanation or could be tightened" — too much removable material to reach level 4.

Actionability

The CLI commands are concrete, copy-paste-ready AWS invocations with --query/--output parameters, covering cost-and-usage pulls, idle EBS/EIP/EC2/snapshot detection, and rightsizing — matching "Mostly executable guidance; concrete code or commands with minor gaps". It falls short of level 5 because several advertised capabilities (RI/Savings Plans analysis, S3 lifecycle candidates, data transfer costs, Lambda memory) have no accompanying command, leaving gaps in coverage of the common cases.

Workflow Clarity

The Optimization Workflow lists a clear four-phase sequence and the boundary section states that "Low CPU or unattached state alone does not establish deletion safety" and destructive actions "require explicit authorized scope and a recovery plan", but validation checkpoints are not embedded in the destructive workflow steps themselves — no verify/snapshot-before-delete feedback loop appears in the sequence, matching "Steps listed but validation gaps; checkpoints missing or implicit". It does not reach level 4 because the destructive-operation validation lives in prose outside the workflow rather than as explicit checkpoints, and per the guidelines missing verification in destructive/batch workflows caps this dimension at 3.

Progressive Disclosure

This is a single ~194-line SKILL.md with no bundle files; sections are well-organized with clear headers, but ~65 lines of CLI command reference plus filler sections (Example Prompts, Kiro integration) are all inlined, fitting "Some structure but could be better organized; content that should be separate is inline". It is not level 2 because the structure is far from a monolithic wall of text, but not level 4 because bulk command reference and non-core material were never split into reference files.

Specificity

The description names the domain ("AWS cost") and two fairly generic actions — "cost analysis" and "optimization recommendations" — plus the tools ("using AWS CLI and Cost Explorer"), but does not list several specific concrete actions. It is not level 4 because it lacks the enumerated capabilities (idle resource detection, rightsizing, EBS/snapshot cleanup) seen in the level-4 anchor; not level 2 because the tools named and the two actions go beyond a bare domain mention. The opener "Comprehensive" is an over-claim buzzword the guidelines penalize.

Completeness

The "what" is clear (AWS cost analysis and optimization recommendations via AWS CLI and Cost Explorer), but there is no "when" — no "Use when..." clause or equivalent trigger guidance, which per the judging guidelines caps completeness at 3. Not level 4/5 for exactly this missing explicit trigger; not level 2 because the "what" half is concrete rather than vague.

Trigger Term Quality

Relevant natural keywords like "AWS", "cost", and "Cost Explorer" are present, matching "Some relevant keywords but missing common variations or synonyms". It is not level 4 because common user phrasings are absent: "AWS bill", "spending", "billing", "cloud waste", "savings" — the exact terms a user would naturally say when needing this skill.

Distinctiveness Conflict Risk

"AWS cost analysis and optimization ... using AWS CLI and Cost Explorer" carves out a mostly distinct niche with tool-specific triggers, matching "Mostly distinct; minor overlap risk with closely related skills". It is not level 5 because the description lacks explicit trigger phrases and could overlap with broader cloud-finops or general AWS skills; not level 3 because naming Cost Explorer and the AWS CLI narrows it well beyond "somewhat specific".