> ## Documentation Index
> Fetch the complete documentation index at: https://docs.semgrep.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Rules

<CardGroup cols={2}>
  <Card title="Change rule severity and other metadata by forking rules" href="/kb/rules/changing-rule-severity-and-other-metadata" icon="file">
    Change rule severity and other metadata by forking rules.
  </Card>

  <Card title="Matching multiple tokens with ellipsis metavariables" href="/kb/rules/ellipsis-metavariables" icon="file">
    Ellipsis metavariables can help with matching multiple word tokens.
  </Card>

  <Card title="How to exclude certain file types for a particular rule" href="/kb/rules/exclude_rule_for_certain_filetypes" icon="file">
    Exclude file types that generate false positives for a specific rule.
  </Card>

  <Card title="Match the absence of something in a file" href="/kb/rules/match-absence" icon="file">
    Approximate absence checks by matching a file and excluding desired content.
  </Card>

  <Card title="Match comments with Semgrep" href="/kb/rules/match-comments" icon="file">
    Use generic pattern matching mode to match comments in code files.
  </Card>

  <Card title="Fix pattern parse errors when running rules" href="/kb/rules/pattern-parse-error" icon="file">
    Implement rule patterns that include a target language's reserved words.
  </Card>

  <Card title="Rule upgrades and supersession" href="/kb/rules/pro-vs-community-secrets-vs-code-rules" icon="file">
    Understand supersession between Community and Pro rules and across products.
  </Card>

  <Card title="Performance principles for rules and files to abide by when scanning repositories" href="/kb/rules/rule-file-perf-principles" icon="file">
    Follow rule and file performance principles to optimize scan times.
  </Card>

  <Card title="Why do new rules keep appearing in Comment or Block mode?" href="/kb/rules/ruleset-default-mode" icon="file">
    Change the default mode for a ruleset.
  </Card>

  <Card title="Run all available rules on a repository" href="/kb/rules/run-all-available-rules" icon="file">
    Learn how to run all available rules on your repository.
  </Card>

  <Card title="How does Semgrep assign severity levels to rules?" href="/kb/rules/understand-severities" icon="file">
    Understand how rule severity and confidence are determined.
  </Card>

  <Card title="My rule with pattern-not doesn't work: using pattern-not-inside" href="/kb/rules/using-pattern-not-inside" icon="file">
    Fix issues with `pattern-not` when excluding cases in custom rules.
  </Card>

  <Card title="Use the Semgrep rule schema to write rules in VS Code" href="/kb/rules/using-semgrep-rule-schema-in-vscode" icon="file">
    Use the Semgrep rule schema in VS Code to make rule writing easier.
  </Card>
</CardGroup>