semgrep-rule-creator

Creates custom Semgrep rules for detecting security vulnerabilities and code patterns. Guides you through a test-first workflow: write tests, analyze the AST, write the rule, iterate until all tests pass. Supports both pattern matching and taint mode for data flow analysis. Hand-writing Semgrep rules without guidance leads to overly broad patterns with high false positives — this skill enforces AST analysis, mandatory test cases including safe variants, and taint mode selection to produce rules that actually work in production.