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deprecation-and-migration

Manages deprecation and migration. Use when removing old systems, APIs, or features. Use when migrating users from one implementation to another. Use when deciding whether to maintain or sunset existing code.

45

Quality

47%

Does it follow best practices?

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tessl review fix ./skills/deprecation-and-migration/SKILL.md

The canonical home for this skill is deprecation-and-migration in addyosmani/agent-skills

SKILL.md
Quality
Evals
Security

Quality

Content

27%Scale 1-3

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

This skill reads more like an engineering philosophy document or blog post than an actionable skill for Claude. It spends significant tokens explaining concepts Claude already knows (Hyrum's Law, code-as-liability, adapter patterns) and provides mostly conceptual guidance rather than concrete, executable instructions. The content would benefit greatly from aggressive trimming and restructuring into a concise overview with references to detailed sub-documents.

Suggestions

Cut the 'Core Principles' and 'Common Rationalizations' sections entirely — Claude already understands these concepts. Focus tokens on the specific decision framework and migration steps.

Extract migration patterns (Strangler, Adapter, Feature Flag) into a separate PATTERNS.md file and reference it from the main skill.

Add explicit validation checkpoints with concrete commands/scripts between migration phases, especially before the 'Remove the Old System' step (e.g., specific metrics queries or dependency analysis commands).

Reduce the overall content to under 80 lines by assuming Claude's intelligence — keep only the deprecation decision checklist, the 4-step migration process with validation gates, and the final verification checklist.

DimensionReasoningScore

Conciseness

Extremely verbose. Explains concepts Claude already knows well (Hyrum's Law, Strangler Pattern, Adapter Pattern, feature flags, what zombie code is). The 'Core Principles' section explains that code has maintenance cost — something Claude deeply understands. The 'Common Rationalizations' table, while potentially useful, is padded with obvious rebuttals. Much of this reads like a blog post or engineering handbook rather than a skill that adds novel, actionable knowledge.

1 / 3

Actionability

There are some concrete elements — the deprecation notice template, the adapter pattern code example, the feature flag example, and the verification checklist. However, much of the content is conceptual guidance and decision frameworks rather than executable steps. The code examples are illustrative but not directly copy-paste usable for a real deprecation task. The skill describes rather than instructs in many sections.

2 / 3

Workflow Clarity

The four-step migration process (Build → Announce → Migrate → Remove) provides a clear sequence, and Step 4 includes a verification step. However, the incremental migration in Step 3 lacks explicit validation checkpoints beyond 'confirm no regressions.' The Strangler Pattern phases are listed but lack validation gates between phases. For destructive operations like code removal, the verification could be more rigorous with explicit feedback loops.

2 / 3

Progressive Disclosure

This is a monolithic wall of text at ~200+ lines with no references to external files and no bundle files. Content like the migration patterns, common rationalizations table, and zombie code section could easily be split into separate reference documents. Everything is inline with no navigation structure beyond flat headings.

1 / 3

Total

6

/

12

Passed

Description

67%Scale 1-3

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 has good structural completeness with explicit 'Use when' clauses covering multiple scenarios, which is its strongest aspect. However, the capabilities described are somewhat high-level and lack concrete specific actions, and the trigger terms could be expanded to cover more natural user language variations. The domain is moderately distinct but could overlap with general code maintenance or API design skills.

Suggestions

Add more concrete actions such as 'writes migration scripts, generates deprecation notices, creates compatibility layers, plans phased rollouts'.

Expand trigger terms to include common variations like 'legacy code', 'backward compatibility', 'breaking changes', 'end-of-life', 'EOL', 'version upgrade'.

DimensionReasoningScore

Specificity

Names the domain (deprecation and migration) and mentions some actions like 'removing old systems', 'migrating users', and 'deciding whether to maintain or sunset', but these are fairly high-level and not concrete specific actions (e.g., no mention of writing migration scripts, generating deprecation notices, versioning APIs, etc.).

2 / 3

Completeness

Clearly answers both 'what' (manages deprecation and migration) and 'when' with explicit 'Use when...' clauses covering three distinct trigger scenarios: removing old systems, migrating users between implementations, and deciding on maintenance vs. sunsetting.

3 / 3

Trigger Term Quality

Includes relevant terms like 'deprecation', 'migration', 'APIs', 'sunset', and 'old systems', which are natural terms a user might use. However, it misses common variations like 'breaking changes', 'backward compatibility', 'version upgrade', 'legacy code', 'end-of-life', or 'EOL'.

2 / 3

Distinctiveness Conflict Risk

The deprecation/migration niche is reasonably distinct, but terms like 'APIs', 'features', and 'existing code' are broad enough to potentially overlap with general code maintenance, API design, or refactoring skills.

2 / 3

Total

9

/

12

Passed

Validation

100%

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

Validation11 / 11 Passed

Validation for skill structure

No warnings or errors.

Repository
finlay611/agent-skills
Reviewed

Table of Contents

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