tsdown
Bundle TypeScript and JavaScript libraries with blazing-fast speed powered by Rolldown. Use when building libraries, generating type declarations, bundling for multiple formats, or migrating from tsup.
86
82%
Does it follow best practices?
Impact
Pending
No eval scenarios have been run
Passed
No known issues
Quality
Discovery
100%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 strong skill description that clearly communicates what the skill does (bundle TS/JS libraries using Rolldown) and when to use it (building libraries, type declarations, multi-format bundling, tsup migration). It uses third person voice, includes natural trigger terms, and is concise without unnecessary fluff. The only minor note is 'blazing-fast speed' is slightly promotional but doesn't detract meaningfully from the description's utility.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions: 'Bundle TypeScript and JavaScript libraries', 'generating type declarations', 'bundling for multiple formats', 'migrating from tsup'. These are clear, actionable capabilities. | 3 / 3 |
Completeness | Clearly answers both what ('Bundle TypeScript and JavaScript libraries... powered by Rolldown') and when ('Use when building libraries, generating type declarations, bundling for multiple formats, or migrating from tsup') with explicit trigger guidance. | 3 / 3 |
Trigger Term Quality | Includes strong natural keywords users would say: 'TypeScript', 'JavaScript', 'libraries', 'type declarations', 'multiple formats', 'tsup', 'bundling'. These cover common variations of how users would describe this need. | 3 / 3 |
Distinctiveness Conflict Risk | Highly distinctive with specific tool references (Rolldown, tsup) and a clear niche (library bundling with type declarations). Unlikely to conflict with general build tools or other bundler skills due to the specific technology mentions. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
64%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This is a comprehensive and highly actionable skill for tsdown with excellent concrete examples and well-organized reference tables. Its main weaknesses are verbosity (too many inline examples that could be deferred to reference files) and lack of workflow validation/error-handling guidance. Trimming the common patterns section and adding troubleshooting steps would significantly improve it.
Suggestions
Reduce the Common Patterns section to 3-4 essential examples and move the rest to a referenced patterns file, keeping the SKILL.md as a concise overview
Add a brief troubleshooting or validation section covering how to verify build output and debug common errors (e.g., missing exports, declaration generation failures)
Remove best practices that Claude would already know (e.g., 'use tree shaking for optimal bundle size', 'enable minification for production') to improve conciseness
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill is fairly well-organized but is quite long (~300 lines). Many of the common patterns and best practices sections repeat information that could be consolidated. The reference tables are efficient, but the sheer volume of inline examples (13+ config examples) makes this more verbose than necessary for a skill that references detailed docs. Some best practices like 'use tree shaking' and 'enable minification' are obvious to Claude. | 2 / 3 |
Actionability | Excellent actionability throughout — every configuration pattern includes complete, copy-paste-ready TypeScript config examples and CLI commands. The quick start section provides concrete install and usage commands, and the common patterns section covers a wide range of real-world scenarios with executable code. | 3 / 3 |
Workflow Clarity | The skill covers a build tool where the primary workflow is straightforward (configure → build), but there's no explicit validation or error-handling guidance. For a bundler skill, there should be guidance on what to do when builds fail, how to verify output correctness, or how to debug common issues. The migration workflow (tsdown-migrate) lacks any validation steps. | 2 / 3 |
Progressive Disclosure | The reference tables provide excellent navigation to detailed docs, but the SKILL.md itself contains too much inline content that should live in those reference files. The 13+ common patterns and 9 best practices could be summarized more briefly with pointers to references. However, since no bundle files were provided, the reference structure appears well-designed based on the links alone. | 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.
Validation — 11 / 11 Passed
Validation for skill structure
No warnings or errors.
- Repository
- antfu/skills
- Commit
50deaeb
- Reviewed
Table of Contents
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