Conciseness

The ~440-line body is largely a textbook SQLi payload catalog — UNION column counting via ORDER BY, classic auth-bypass strings (' OR '1'='1), SLEEP-based blind extraction, comment-substitution filter evasion — all of which Claude already knows, which the guidelines explicitly penalize. It is noticeably verbose with several redundant sections (payload lists repeated in Quick Reference and Examples). Above 1 because it is structured reference material rather than padded prose explanation.

Actionability

Payloads are concrete and copy-paste ready, and the worked examples show full HTTP requests with expected responses ("GET /product.php?id=5 ORDER BY 4-- / Response: Normal"). Below 5 because named prerequisites (SQLMap, Burp Suite) never get a single invocation example — the tools are required but their use is left entirely to inference.

Workflow Clarity

A clear four-phase sequence (detection, exploitation, auth bypass, filter bypass) with embedded confirmations — true/false response comparison, ORDER BY-until-error column enumeration, delay confirmation — and a Troubleshooting section for error recovery. Below 5 because validation checkpoints are implicit inside phases rather than explicit gate steps, and the destructive-operation cap does not apply since destructive queries are explicitly forbidden in Constraints.

Progressive Disclosure

No bundle files exist at all: the entire skill is a monolithic SKILL.md where payload catalogs, quick-reference tables, and worked examples clearly belong in separate references/ files. Section headers are good, so above anchor 2 (no structure), but it matches anchor 3: content that should be separate is inlined with no one-level-deep references.

Specificity

The description names the domain and verbs ("identifying, exploiting, and understanding SQL injection attack vectors") but the actions are generic and rest on the buzzword "comprehensive techniques"; no concrete capabilities (schema extraction, login bypass, payload testing) are stated. This matches the anchor 'names domain and 1-2 concrete actions, but not comprehensive' — below 4 which requires several specific actions, above 2 because real actions are named.

Completeness

Both halves are explicit: an explicit trigger clause ("This skill should be used when the user asks to...") with concrete quoted phrases, and a stated "what" ("provides comprehensive techniques for identifying, exploiting, and understanding SQL injection attack vectors across different database systems"). Below 5 because the "what" leans on the vague "comprehensive techniques" rather than concrete capabilities; above 3 because the "when" is explicit, not merely implied.

Trigger Term Quality

Six natural quoted trigger phrases cover the space well, including the abbreviation synonym "perform SQLi attacks" plus test/detect/extract/bypass/exploit variations ("test for SQL injection vulnerabilities", "detect SQL injection flaws", "bypass authentication using SQL injection"). This is comprehensive natural-term coverage with synonyms, matching the top anchor.

Distinctiveness Conflict Risk

SQL injection testing is a clear niche with distinct, specific trigger phrases ("test for SQL injection vulnerabilities", "perform SQLi attacks") that no other skill category would claim. Voice is third person ("This skill should be used"), so no penalty applies. Minimal conflict risk matches the top anchor.