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svelte-migrate

Migrate a Svelte 4 component to Svelte 5 runes syntax. Use when asked to migrate, convert, or upgrade a .svelte file to Svelte 5.

87

1.06x
Quality

83%

Does it follow best practices?

Impact

92%

1.06x

Average score across 3 eval scenarios

SecuritybySnyk

Passed

No known issues

SKILL.md
Quality
Evals
Security

Quality

Content

77%

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

This is a strong, highly actionable migration guide with excellent before/after examples covering all major Svelte 4→5 patterns. Its main weakness is length — at ~300 lines with 13 inline patterns, it consumes significant context window space that could be reduced by moving less common patterns to a reference file. The workflow is well-sequenced with a verification step, and the 'Important Notes' section effectively prevents common migration mistakes.

Suggestions

Consider splitting less common migration patterns (e.g., dynamic components, class directives, app state) into a separate REFERENCE.md to reduce the main file's token footprint

Remove the hedging in section 12 ('either works') — pick the recommended approach or drop the section since class: directives still work unchanged

DimensionReasoningScore

Conciseness

The skill is comprehensive but quite long (~300 lines). The before/after pattern is effective but some sections could be consolidated (e.g., sections 6 and 7 on component events and forwarding could merge). The class: directive section hedges ('either works') which is unnecessary. However, it avoids explaining what Svelte is or basic concepts, so it respects Claude's intelligence.

2 / 3

Actionability

Every migration pattern includes fully executable before/after code examples in proper Svelte syntax with TypeScript. The examples are copy-paste ready and cover edge cases (e.g., slots with props, event modifiers, bindable props). The workflow section provides a clear systematic order and ends with a concrete verification command (`pnpm check`).

3 / 3

Workflow Clarity

The workflow section provides a clear 6-step sequence with a logical ordering (props first, then state, derived, effects, events, slots). It includes a validation checkpoint at the end (`pnpm check`). The 'Important Notes' section acts as a checklist of things NOT to change, which prevents common errors. The ordering rationale (props first) is sound since later transformations depend on prop structure.

3 / 3

Progressive Disclosure

The content is a monolithic file with 13 migration patterns inline. While well-organized with clear headers, the sheer volume (especially sections like slots with multiple sub-patterns) could benefit from being split into a reference file, with SKILL.md containing just the workflow and most common patterns. No bundle files exist to offload content to.

2 / 3

Total

10

/

12

Passed

Description

89%

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

This is a well-crafted, concise description that clearly identifies its niche (Svelte 4 to 5 migration) and provides explicit trigger guidance with natural user terms. Its main weakness is that it could list more specific concrete actions involved in the migration (e.g., converting reactive declarations to $state/$derived, updating event directives) to better inform Claude about the scope of the skill.

Suggestions

Add specific concrete actions to improve specificity, e.g., 'Converts reactive declarations ($:) to $state/$derived runes, updates event handlers, replaces onMount/onDestroy with $effect.'

DimensionReasoningScore

Specificity

It names the domain (Svelte 4 to Svelte 5 migration) and one action ('migrate a component to runes syntax'), but doesn't list multiple specific concrete actions like converting reactive declarations, updating event handlers, replacing stores, etc.

2 / 3

Completeness

Clearly answers both 'what' (migrate a Svelte 4 component to Svelte 5 runes syntax) and 'when' (Use when asked to migrate, convert, or upgrade a .svelte file to Svelte 5), with explicit trigger guidance.

3 / 3

Trigger Term Quality

Includes strong natural trigger terms: 'migrate', 'convert', 'upgrade', '.svelte file', 'Svelte 5', 'Svelte 4', 'runes syntax'. These cover the common variations a user would naturally say when requesting this task.

3 / 3

Distinctiveness Conflict Risk

Very clear niche targeting specifically Svelte 4→5 migration with runes syntax. Unlikely to conflict with general Svelte development skills or other framework migration skills due to the specific version and technology references.

3 / 3

Total

11

/

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
temporalio/ui
Reviewed

Table of Contents

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