Input Validation Base Skill

Role: Shared Python module providing input validation functions for plan-marshall scripts. Prevents path traversal, invalid plan IDs, and malformed inputs from reaching filesystem operations.

Enforcement

Execution mode: Library module; import validators as documented in usage examples.

Prohibited actions:

• Do not validate plan IDs with custom regex; use validate_plan_id()
• Do not validate file paths without validate_relative_path()
• Do not bypass validation in scripts that accept user/LLM input

Constraints:

• All plan IDs must match ^[a-z][a-z0-9-]*$
• Relative paths must reject absolute paths and traversal sequences
• Use raising validators for fail-fast behavior, bool validators for conditional logic

What This Skill Provides