counterexample-explainer

Explain why counterexamples violate specifications by analyzing formal specifications (temporal logic, invariants, pre/postconditions, code contracts), informal requirements (user stories, acceptance criteria), test specifications (assertions, property-based tests), and providing step-by-step traces showing state changes, comparing expected vs actual behavior, identifying root causes, and assessing violation impact. Use when debugging test failures, understanding model checker output, explaining runtime assertion violations, analyzing static analysis warnings, or teaching specification concepts. Produces structured markdown explanations with traces, comparisons, state diagrams, and cause chains. Triggers when users ask why something failed, explain a violation, understand a counterexample, debug a specification, or analyze why a test fails.

1.45x

Quality

81%

Does it follow best practices?

Impact

96%

1.45x

Average score across 3 eval scenarios

Securityby

Passed

No findings from the security scan

Quality

Content

63%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.

The body is well-structured and actionable with good progressive disclosure via two real reference files, but it is markedly verbose: it duplicates full templates and re-teaches fundamentals Claude already knows. Trimming redundant explanations and folding repeated template blocks into the reference files would lift the weakest dimension.

Suggestions

Move the full markdown trace/comparison/impact templates into explanation-patterns.md and keep only a compact skeleton inline, eliminating duplicated template blocks across Steps 4–8.

Cut the conceptual re-explanations of basic error types (off-by-one, race conditions, missing validation) — Claude already knows these; retain only the counterexample-specific framing.

Reduce the two worked examples to one concise end-to-end example to avoid re-demonstrating the same trace structure twice.

Dimension	Reasoning	Score
Conciseness	The ~590-line body repeats full markdown templates inline and re-explains concepts Claude already knows (off-by-one, race conditions, what an invariant is), with two fully worked examples that largely duplicate the templates — noticeably verbose with several padded sections.	2 / 5
Actionability	Provides copy-paste-ready markdown templates and concrete code examples (pytest commands, assertion traces, root-cause fixes), though templates lean on [placeholder] brackets rather than fully concrete content, leaving minor gaps.	4 / 5
Workflow Clarity	An explicit, well-sequenced 8-step workflow is present; because this is an explanatory (non-destructive, non-batch) skill the validation cap does not apply, but explicit validation/checkpoint cues are still absent, keeping it just below 5.	4 / 5
Progressive Disclosure	Both referenced files (specification-types.md, explanation-patterns.md) exist and are linked inline at the relevant steps and again in a Reference section, one level deep and clearly signaled — easy navigation.	5 / 5
	Total	15 / 20 Passed

Description

100%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.

The description is exceptionally thorough: it states concrete capabilities, provides explicit and varied trigger phrases for both what and when, and carves out a distinct niche. It is long but every clause earns its place.

Dimension	Reasoning	Score
Specificity	Lists multiple concrete actions — 'analyzing formal specifications', 'providing step-by-step traces showing state changes, comparing expected vs actual behavior, identifying root causes, and assessing violation impact', plus 'structured markdown explanations with traces, comparisons, state diagrams, and cause chains' — with comprehensive coverage.	5 / 5
Completeness	Explicitly answers both what (analyzes specifications and produces structured markdown explanations) and when (concrete 'Use when...' and 'Triggers when...' clauses with multiple specific trigger phrases).	5 / 5
Trigger Term Quality	Comprehensive natural trigger phrases users would actually say: 'why something failed', 'explain a violation', 'understand a counterexample', 'debug a specification', 'analyze why a test fails', plus 'debugging test failures, understanding model checker output'.	5 / 5
Distinctiveness Conflict Risk	Occupies a clear niche — counterexample/violation explanation — with distinct triggers unlikely to fire for unrelated skills; minimal conflict risk.	5 / 5
	Total	20 / 20 Passed

Validation

93%

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 — 15 / 16 Passed

Validation for skill structure

Criteria	Description	Result
skill_md_line_count	SKILL.md is long (598 lines); consider splitting into references/ and linking	Warning

	Total	15 / 16 Passed

Repository: ArabelaTso/Skills-4-SE
Path: skills/counterexample-explainer/SKILL.md
Commit: 4f38503

Reviewed: 7 days ago

Table of Contents

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