This is an excellent skill description that clearly articulates specific technical actions (code verifier generation, session cookie management, callback handling), explains what it replaces (implicit token-in-fragment flows), and provides explicit trigger conditions covering multiple natural user scenarios. It is highly distinctive and would be easy for Claude to correctly select from a large pool of skills.

Dimension	Reasoning	Score
Specificity	Lists multiple specific concrete actions: generates code verifier/challenge pairs, exchanges authorization codes for sessions, sets secure HTTP-only session cookies, configures server-side callback handling, removes hash-based token extraction and localStorage usage.	3 / 3
Completeness	Clearly answers both 'what' (generates code verifier/challenge pairs, exchanges auth codes, sets cookies, configures callbacks, replaces implicit flows) and 'when' with an explicit 'Use when...' clause listing five trigger scenarios.	3 / 3
Trigger Term Quality	Includes strong natural keywords users would say: 'Supabase authentication', 'OAuth login', 'secure browser auth', 'SSR auth setup', 'auth flow migration', plus technical terms like 'PKCE', 'HTTP-only session cookies', 'authorization codes' that developers would naturally use.	3 / 3
Distinctiveness Conflict Risk	Highly distinctive with a clear niche: PKCE auth flow implementation specifically for Supabase/OAuth with SSR. The combination of PKCE, Supabase, server-side callback handling, and migration from implicit flows makes it very unlikely to conflict with other skills.	3 / 3
	Total	12 / 12 Passed

Implementation

100%

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

This is an excellent skill that provides concrete, executable guidance for implementing PKCE auth flow with Supabase. It respects Claude's intelligence by skipping conceptual explanations, includes strong validation checkpoints (HALT conditions), and appropriately delegates framework-specific variants to separate files. The verification checklist at the end ties everything together.

Dimension	Reasoning	Score
Conciseness	The content is lean and efficient. It doesn't explain what PKCE is, what OAuth is, or how cookies work — it assumes Claude knows these concepts and jumps straight to actionable configuration and code. Every section earns its place.	3 / 3
Actionability	Provides fully executable, copy-paste-ready TypeScript code for both the callback route and middleware. Specific framework paths (e.g., `app/auth/callback/route.ts`, `middleware.ts`) and exact method calls (`exchangeCodeForSession`, `getUser`) are given.	3 / 3
Workflow Clarity	Clear four-phase sequence with explicit HALT conditions at each phase serving as validation checkpoints. The verification checklist at the end provides a final validation gate. Error recovery is implicit in the HALT directives, and the flow from configure → implement → secure → clean up is logical and well-sequenced.	3 / 3
Progressive Disclosure	The main skill covers the primary framework (Next.js) inline with complete examples, while appropriately deferring SvelteKit-specific implementations to `SVELTEKIT.md` with clear one-level-deep references. Content is well-structured with phases and a verification checklist.	3 / 3
	Total	12 / 12 Passed

Validation

100%

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 — 11 / 11 Passed

Validation for skill structure

No warnings or errors.

Reviewed

7 days ago

Table of Contents

Discovery Implementation Validation