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Rule Authoring

Add reviewed organization-specific checks without changing the built-in scanner.

Version Public source Maintained security documentation Reviewed Jul 21, 2026 Next review Sep 21, 2026

Owner: Batoi Engineering Reviewed by: MCP Audit Maintainers Source revision: 8140371

Browse MCP Audit Documentation Rule Authoring

Rule Authoring

Custom rules extend built-in checks for an organization's known server patterns, prohibited launchers, authentication expectations, or tool-description policies.

A rule defines a stable identifier, title, severity, category, target, one or more match conditions, a clear finding message, and actionable remediation. Supported comparisons include equality, containment, regular expressions, existence, and grouped all-or-any conditions.

Rules can inspect normalized server names, commands, arguments, environment keys, transports, URLs, tool names and descriptions, combined tool text, and authentication types.

Review Standard

  • Keep the identifier stable after publication.
  • Match the narrowest reliable signal.
  • Explain the risk without exposing secrets from the scanned configuration.
  • Provide remediation that a reviewer can verify.
  • Test a positive case, a safe negative case, and malformed input.
  • Record ownership and review the rule when the underlying threat changes.