Project Zero iPhone Messaging Tools is a collection of testing utilities developed by Google's Project Zero team for analyzing iPhone messaging systems. The repository includes three main components: - SmsSimulator: A tool for simulating SMS messages on iPhone devices - iMessage tools: Utilities specifically designed for testing and analyzing iMessage functionality - imapiness: An IMAP client fuzzing tool for testing email protocol implementations These tools are designed for security research and testing purposes, allowing researchers to examine messaging protocols and identify potential vulnerabilities in iPhone communication systems. The tools provide capabilities for message simulation, protocol analysis, and fuzzing operations against messaging infrastructure. Each tool within the repository includes its own documentation with detailed usage instructions and implementation guidance. The project is maintained as a research initiative and is not considered an officially supported Google product.