behavior-preservation-checker

Compare runtime behavior between original and migrated repositories to detect behavioral differences, regressions, and semantic changes. Use when validating code migrations, refactorings, language ports, framework upgrades, or any transformation that should preserve behavior. Automatically compares test results, execution traces, API responses, and observable outputs between two repository versions. Provides actionable guidance for fixing deviations and ensuring behavioral equivalence.

2.62x

Quality

73%

Does it follow best practices?

Impact

97%

2.62x

Average score across 3 eval scenarios

Securityby

Passed

No findings from the security scan

Fix and improve this skill with Tessl

tessl review fix ./skills/behavior-preservation-checker/SKILL.md

Quality

Content

53%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 content is well-structured and mostly actionable, but suffers from verbosity, six missing referenced scripts, and a lack of explicit validation feedback loops in its core workflow. Tightening the inlined methods/patterns into references and adding verify-before-proceed checkpoints would raise it substantially.

Suggestions

Add the six missing scripts referenced in the body (compare_api_outputs.py, isolate_difference.py, find_missing_functions.py, compare_api_contracts.py, benchmark_comparison.py, detect_state_issues.py) or remove those command examples, so the documented commands are actually executable.

Insert explicit validation checkpoints into the core workflow — e.g., after running comparisons, a 'validate report -> triage critical differences -> fix -> re-run' feedback loop — to satisfy the batch-operation validation requirement.

Move the four comparison methods and five actionable-guidance patterns into the existing reference files (comparison_techniques.md, difference_patterns.md), keeping SKILL.md a concise overview with one-level-deep links.

Dimension	Reasoning	Score
Conciseness	The body is mostly efficient with concrete code examples and little 'what is X' padding, but it is noticeably verbose with repetition across four comparison methods and five patterns and some unnecessary explanatory sections (severity levels, basic equality/tolerance snippets). It fits the 'mostly efficient but could be tightened' anchor.	3 / 5
Actionability	Provides concrete, copy-paste-ready commands and code throughout, but six of the ten referenced scripts (compare_api_outputs.py, isolate_difference.py, find_missing_functions.py, compare_api_contracts.py, benchmark_comparison.py, detect_state_issues.py) do not exist in the bundle, so those examples are not actually executable — a significant gap keeping it below 4.	3 / 5
Workflow Clarity	The core workflow lists four sequenced steps, but Step 4 ('Fix Deviations') is vague ('Follow actionable guidance') and there are no explicit validation checkpoints or validate→fix→retry feedback loops. Per the rubric cap, missing validation for batch/comparison operations caps this at 3.	3 / 5
Progressive Disclosure	Good structure with two real reference files (comparison_techniques.md, difference_patterns.md) and scripts, clearly signaled in a Resources section. Not a 5 because substantial content that could live in the references (five detailed patterns, four comparison methods) is inlined in SKILL.md rather than split out.	4 / 5
	Total	13 / 20 Passed

Description

92%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 specific, complete, and distinct, clearly stating both what the skill does and when to use it with concrete natural-language triggers. It is only slightly held back on trigger-term breadth, lacking a few colloquial synonyms.

Dimension	Reasoning	Score
Specificity	Lists multiple concrete actions (comparing test results, execution traces, API responses, observable outputs) and provides actionable guidance for fixing deviations, giving comprehensive coverage of what the skill does.	5 / 5
Completeness	Explicitly answers both 'what' ('Compare runtime behavior...detect behavioral differences, regressions, and semantic changes') and 'when' ('Use when validating code migrations, refactorings, language ports, framework upgrades...') with concrete trigger phrases.	5 / 5
Trigger Term Quality	Includes natural trigger phrases users would say ('code migrations, refactorings, language ports, framework upgrades') with good synonym coverage, though missing a few common variations. Not a 5 because it lacks the broader colloquial/extension-style terms seen in the top anchor.	4 / 5
Distinctiveness Conflict Risk	Occupies a clear niche — comparing runtime behavior between two repository versions — with distinct triggers and minimal overlap risk with other skills.	5 / 5
	Total	19 / 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
referenced_paths_exist	Referenced path issues: 6 missing	Warning

	Total	15 / 16 Passed

Repository: ArabelaTso/Skills-4-SE
Path: skills/behavior-preservation-checker/SKILL.md
Commit: 4f38503

Reviewed: 5 days ago

Table of Contents

Discovery Implementation Validation

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.