semgrep-rule-creator

To create custom Semgrep rules for detecting security vulnerabilities, write test cases before authoring the rule and run semgrep --test until all pass. This skill generates the rule files using both taint-mode and pattern-matching syntax.

Taint analysis tracks data flow from untrusted sources to dangerous sinks to detect security bugs. Semgrep applies this through taint-mode rules, which you can author to trace data-flow patterns across your codebase.

Yes, you can use Semgrep pattern-matching to detect bug patterns across multiple languages. The rule creation process supports syntactic detection, allowing you to define code patterns that identify vulnerabilities regardless of the target language.

The best way to write and validate Semgrep rules is a test-first workflow: write test cases before the rule, then run semgrep --test until all pass. Strict validation enforces 100% test pass rates and prevents generic or unsafe rules.

Static analysis rules may fail to catch specific code patterns if they lack strict validation or use unsafe annotations. Enforcing 100% test pass rates and avoiding generic rules ensures accurate detection of security vulnerabilities and bug patterns.