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api-and-interface-design

Guides stable API and interface design. Use when designing APIs, module boundaries, or any public interface. Use when creating REST or GraphQL endpoints, defining type contracts between modules, or establishing boundaries between frontend and backend.

70

Quality

85%

Does it follow best practices?

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SecuritybySnyk

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SKILL.md
Quality
Evals
Security

Quality

Content

82%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.

A high-quality, actionable design skill with concrete executable TypeScript examples, well-structured sections, and a strong verification checklist. The main gaps are minor conciseness trims and the absence of any progressive disclosure to separate reference files for the deeper idempotency material.

Suggestions

Trim elaborative sentences in the Hyrum's Law and error-semantics sections to tighten token efficiency.

Consider externalizing the detailed idempotency-key section (~60 lines) into a reference file linked from the body, improving progressive disclosure for this >50-line skill.

DimensionReasoningScore

Conciseness

Mostly efficient and content-dense with concrete code earning its place and no padding of basic concepts Claude already knows, but a few elaborative sentences (e.g., the Hyrum's Law bullets, 'Don't mix patterns...') could be trimmed.

4 / 5

Actionability

Provides copy-paste-ready, executable TypeScript covering the common cases — a full Express validation handler, TaskAPI contract, APIError shape, status-code mapping, atomic idempotency-key claim, and branded types — matching the anchor for fully executable guidance.

5 / 5

Workflow Clarity

The six numbered principles give an implicit design sequence and the Verification section is an explicit checklist of validation checkpoints, but there is no error-recovery feedback loop, which is acceptable for a design skill yet leaves a minor gap.

4 / 5

Progressive Disclosure

Well-organized into clear sections with one clearly signaled cross-skill reference ('deprecation-and-migration'), but all content is inlined in a single ~360-line file with no bundle files; the deep idempotency dive could be externalized, though splitting is not clearly required.

4 / 5

Total

17

/

20

Passed

Description

88%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.

A strong, third-person description that clearly states both what the skill does and when to use it, with concrete trigger phrases and good keyword coverage. The main weakness is a few missing synonyms and minor overlap risk with adjacent architecture/design skills.

Suggestions

Add a few natural synonyms to broaden trigger matching, e.g., 'API schemas', 'OpenAPI specs', 'component props', or 'SDK contracts'.

Tighten the two consecutive 'Use when' clauses into one to avoid redundancy while preserving trigger coverage.

DimensionReasoningScore

Specificity

Lists multiple concrete design actions — 'designing APIs, module boundaries, or any public interface', 'creating REST or GraphQL endpoints', 'defining type contracts between modules', 'establishing boundaries between frontend and backend' — giving comprehensive coverage of the API/interface design domain.

5 / 5

Completeness

Explicitly answers both what ('Guides stable API and interface design') and when with concrete trigger phrases repeated across two 'Use when' clauses, matching the anchor for clearly answering both.

5 / 5

Trigger Term Quality

Strong natural keywords a developer would say ('APIs', 'REST', 'GraphQL', 'module boundaries', 'type contracts', 'frontend and backend'), but a few plausible synonyms are absent (e.g., 'schema', 'OpenAPI', 'props', 'SDK').

4 / 5

Distinctiveness Conflict Risk

Has a clear niche with distinct triggers (module boundaries, type contracts, frontend/backend boundaries), but 'interface design' and 'module boundaries' could overlap with a general system-design or architecture skill, so minor overlap risk remains.

4 / 5

Total

18

/

20

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.

Validation16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository
addyosmani/agent-skills
Reviewed

Table of Contents

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