semgrep-rule-creator

To create Semgrep rules with tests, follow a test-first workflow by writing test cases before the rule, analyzing the AST, validating the YAML configuration, and running semgrep --test to verify detections pass.

The best way to structure Semgrep rules is placing each rule in its own directory with a dedicated YAML file and test file, applying a test-first workflow to catch false positives and negatives early during static analysis.

Yes, you can use a test-first workflow to generate Semgrep rules for multiple languages. The process analyzes AST patterns and generates YAML rules to detect security vulnerabilities and coding patterns across different codebases.

You validate Semgrep YAML rules by running the semgrep --test command in the rule directory. This executes the dedicated test file against the rule configuration to confirm detections work and tests pass.

Semgrep rules fail to detect vulnerabilities when AST patterns do not match the target code or tests are not written first. Analyze the AST accurately and validate the YAML structure to ensure reliable detections across codebases.