v3.4.0

Added

• Universal ${} Placeholder Syntax: Centralized environment variable resolution system
  • ${ENV_VAR} for environment variables
  • ${cmd: command args} for command execution
  • Support across all configuration fields: command, args, env, url, headers

Deprecated

• Legacy $VAR syntax in args (use ${VAR} instead)
• Legacy $: command syntax in env (use ${cmd: command} instead)
• All deprecated syntax now shows deprecation warnings

Enhanced

• Updated documentation with clear examples of new universal syntax
• Improved configuration section clarity and examples