cfn-behavior-validator

Creates test stacks, analyzes CloudFormation events, compares actual vs documented update behavior, then confirms whether a resource property change triggers replacement rather than an in-place update. Use when: testing if a CFN property change causes resource replacement; investigating stack update behavior, "Update requires" documentation accuracy; validating whether a workaround (e.g. hash-based logical IDs) is actually necessary; questioning UpdateRequiresReplacement behavior for immutable properties; needing empirical evidence before an architectural decision involving CDK/CloudFormation stack updates.

Quality

83%

Does it follow best practices?

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Securityby

Low

Low-risk findings worth noting

Quality

Content

70%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

A well-structured, highly actionable body with an exemplary validation-gated workflow, dragged down by redundant explanation and a broken progressive-disclosure story: the body cites a nonexistent EXAMPLES.md while the real reference guide sits unlinked in references/. Fixing the file pointer and de-duplicating the ENI material would lift the two weakest dimensions.

Suggestions

Point the walkthrough reference at the real file (e.g. 'See references/sns-testing-guide.md for a full SNS email subscription walkthrough') instead of the nonexistent EXAMPLES.md, so the 335-line guide is discoverable.

Remove the duplicated Lambda VPC/ENI-churn explanation — keep it in the 'No interruption' anti-pattern and drop the near-verbatim repeat in Mindset.

Replace the placeholder TypeScript stack skeleton with a minimal runnable example (a real resource driven by tryGetContext) so the design step is copy-paste executable like the bash steps.

Dimension	Reasoning	Score
Conciseness	Mostly efficient, but the Lambda VPC/ENI-churn example appears nearly verbatim in both Mindset and the 'No interruption' anti-pattern, and the 'docs are hand-maintained and drift' idea is repeated across Purpose, Mindset, and the first anti-pattern. Fits 'could be tightened'; not 2 because the anti-pattern WHYs are genuine non-obvious domain gotchas rather than padding.	3 / 5
Actionability	Concrete executable commands throughout — a full describe-stack-events query with --query, continue-update-rollback, and a jq normalization pipeline — but the TypeScript test-stack snippet is a placeholder skeleton ('Add only the resource under test') rather than runnable code. Matches 'mostly executable guidance with minor gaps'; not 5 because of that non-executable skeleton.	4 / 5
Workflow Clarity	The four-step workflow is clearly sequenced and backed by an explicit 'Validation gates' block (initial deploy fails → stop and fix; unexpected events → abort; ambiguous → repeat), giving feedback loops that satisfy the destructive-operation cap. Not 4: checkpoints are explicit, not implicit.	5 / 5
Progressive Disclosure	The scripts table is well-signaled, but the body points to 'EXAMPLES.md in this skill directory' which does not exist, while the actual bundle file references/sns-testing-guide.md (a 335-line SNS walkthrough, i.e. that exact content) is never referenced from SKILL.md. A dangling reference plus an orphaned reference file is more than the 'minor organization gaps' of a 4; the structure is otherwise too good for a 2.	3 / 5
	Total	15 / 20 Passed

Description

96%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong description: concrete action list, dense natural trigger vocabulary including synonyms, and an explicit multi-clause 'Use when:' block. The only weakness is mild breadth in the stack-update triggers that could pull users of a general CDK skill.

Dimension	Reasoning	Score
Specificity	Lists four concrete, distinct actions ('Creates test stacks, analyzes CloudFormation events, compares actual vs documented update behavior, then confirms whether a resource property change triggers replacement'), comprehensively covering the skill's job. Not 4: there are no meaningful gaps in the capability coverage.	5 / 5
Completeness	Explicitly answers both 'what' (first sentence enumerating the actions) and 'when' with a five-clause 'Use when:' block of concrete trigger phrases. Not 4: the 'when' guidance is already fully explicit and specific, not merely present.	5 / 5
Trigger Term Quality	Covers the natural terms users would say — 'CloudFormation' with its synonym 'CFN', 'CDK', 'resource replacement', 'stack update', 'Update requires', 'workaround' — matching the comprehensive-synonyms anchor. Not 4: no common variation or synonym for this domain is missing.	5 / 5
Distinctiveness Conflict Risk	The validation framing ('testing if', 'validating whether', 'needing empirical evidence') carves a clear niche, but 'investigating stack update behavior' and 'CDK/CloudFormation stack updates' overlap with a general AWS CDK skill. Fits the 'mostly distinct; minor overlap risk with closely related skills' anchor better than the minimal-conflict anchor.	4 / 5
	Total	19 / 20 Passed

Validation

100%

Warnings & errors only

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository: pantheon-org/tekhne
Path: skills/infrastructure/cfn/behavior-validator/SKILL.md
Commit: a1083f4

Reviewed: 2 hours ago

Table of Contents

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