better-auth

Guide for implementing Better Auth - a framework-agnostic authentication and authorization framework for TypeScript. Use when adding authentication features like email/password, OAuth, 2FA, passkeys, or advanced auth functionality to applications.

Quality

72%

Does it follow best practices?

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Securityby

Passed

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Fix and improve this skill with Tessl

tessl review fix ./claude/skills/better-auth/SKILL.md

Quality

Content

57%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 body is a thorough, code-rich reference with a clear setup sequence, but it is monolithic: plugin and framework-specific material that belongs in separate reference files is inlined, setup steps lack validation checkpoints for destructive database operations, and there is some redundancy with the description.

Suggestions

Split plugin details, framework-specific handler guides, and advanced configuration into separate reference files under ./references/ and link to them from SKILL.md to improve progressive disclosure.

Add explicit validation checkpoints to the setup workflow (e.g., after 'npx @better-auth/cli generate/migrate', verify the schema was applied and the /api/auth/* route responds) so destructive database operations have a validate-then-proceed feedback loop.

Remove feature/framework lists that duplicate the frontmatter description and trim introductory prose about what authentication is, tightening conciseness without losing actionable code.

Dimension	Reasoning	Score
Conciseness	The ~700-line body is mostly efficient code/config, but repeats framework lists and feature enumerations already covered in the frontmatter description, and includes some explanatory prose Claude already knows; it could be tightened without losing value.	3 / 5
Actionability	Provides extensive executable code and concrete commands (npm install, npx @better-auth/cli generate, framework-specific handlers) across common cases, but several examples contain placeholders ('// Database configuration', undefined sendEmail) that prevent fully copy-paste readiness.	4 / 5
Workflow Clarity	A clear Step 1-7 setup sequence and an implementation checklist exist, but database migration/generation steps lack explicit validation checkpoints, and the destructive/batch database operations have no validate-then-proceed feedback loop, capping the score at 3 per the rubric.	3 / 5
Progressive Disclosure	Section headers give the body reasonable structure, but no bundle files exist and content that clearly belongs in separate references (per-plugin guides, framework-specific guides, advanced config) is all inlined into a single monolithic SKILL.md rather than split with signaled one-level-deep references.	3 / 5
	Total	13 / 20 Passed

Description

87%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 strong: it names a specific framework, lists concrete auth capabilities, and provides an explicit 'Use when' trigger clause with natural terms. Minor gains are possible by adding synonyms like 'login' or 'sign-in' and a more active verb than 'Guide for implementing'.

Dimension	Reasoning	Score
Specificity	Names the domain ('framework-agnostic authentication and authorization framework for TypeScript') and lists several concrete feature actions ('email/password, OAuth, 2FA, passkeys'), though the umbrella verb 'Guide for implementing' is slightly generic, keeping it just below a 5.	4 / 5
Completeness	Explicitly answers both 'what' ('Guide for implementing Better Auth... framework for TypeScript') and 'when' ('Use when adding authentication features like email/password, OAuth, 2FA, passkeys...') with concrete trigger phrases.	5 / 5
Trigger Term Quality	Includes natural user-facing terms ('authentication', 'email/password', 'OAuth', '2FA', 'passkeys') with a clear 'Use when adding authentication features like...' trigger, but is missing some common synonyms (e.g., 'login', 'sign-in', 'social login').	4 / 5
Distinctiveness Conflict Risk	Names a specific framework (Better Auth) with a clear TypeScript niche and distinct auth-feature triggers, giving minimal overlap risk with other skills.	5 / 5
	Total	18 / 20 Passed

Validation

87%

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 — 14 / 16 Passed

Validation for skill structure

Criteria	Description	Result
skill_md_line_count	SKILL.md is long (720 lines); consider splitting into references/ and linking	Warning
frontmatter_unknown_keys	Unknown frontmatter key(s) found; consider removing or moving to metadata	Warning

	Total	14 / 16 Passed

Repository: einverne/dotfiles
Path: claude/skills/better-auth/SKILL.md
Commit: 837e856

Reviewed: ~7 hours ago

Table of Contents

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