The payload listings are the catalog's core value (not padding), but the opening OWASP/CWE/ISTQB terminology blockquote, per-class "Modern context" prose, and the defensive-mitigation table restate well-known concepts Claude already knows and could be trimmed; it is mostly efficient but not fully lean, matching the 2 anchor rather than the every-token-earns-its-place 3.

Copy-paste-ready payload strings, a per-context selection table, and two complete executable pytest examples (parametrized negative test and a Hypothesis fuzz target) match the fully-executable/copy-paste-ready anchor; it is not the pseudocode-or-incomplete anchor of 2.

A clear selection workflow (identify context -> pick payload class via the table -> apply, with "How to use in tests" worked examples) plus assertion-based validation in the examples provides explicit checkpoints; for a self-contained reference skill this is well-organized, matching the 3 anchor rather than the sequence-with-gaps anchor of 2.

The body is self-contained with no bundle files present and is organized into clear sections (When to use, Payload classes, Per-context selection, How to use, Anti-patterns, Defensive guidance, References); external references are one level deep and clearly signaled, with no nested-reference chains, matching the 3 anchor rather than the monolithic-or-undersignaled 2.

The description enumerates concrete payload classes ("SQL injection, XSS, SSRF, path traversal, command injection, XXE, prototype pollution, regex DoS, Unicode confusables, header injection") and concrete application contexts ("URL parameter / form input / JSON body / file upload"), matching the anchor for multiple specific concrete actions; it is not the vague single-domain phrasing of a 2.

It states both what it is ("Reference catalog of curated adversarial input payloads keyed by attack class ... plus per-context guidance") and when to use it via an explicit "Use when authoring negative-test cases ..." clause, satisfying the both-what-and-when anchor; not the what-only anchor of 2.

Natural practitioner phrasing appears directly: "negative-test cases for input validation", "fuzz targets", "security-focused test suite", "OWASP Top 10 attack surface" — terms a user would actually say; it is not the jargon-only or partial-coverage language of lower anchors.

The niche is narrow and distinctive (an adversarial-input payload bank for defensive testing) with triggers unlikely to fire for unrelated skills; it is far more specific than the overlapping "Works with document files" anchor of 2.