Abstract: We discuss our experiences with deploying a tool called the Requirements Analysis Tool (RAT), which automatically reviews requirements documents for clarity and content based issues using a variety of syntactic and semantic techniques. The tool has been deployed at over 500 large software projects. We provide an overview of our syntactic approach, which is based on enforcing restrictions on both sentence structure and vocabulary in a way that is carefully chosen to align with best practices. We discuss how RAT analyzes natural language text to find defects such as terminological inconsistencies and missing contextual information. Structured content from requirements is then represented as a semantic graph and RAT performs semantic analysis to help users perform interaction analysis. We present a number of case studies based on real world deployments of RAT which demonstrate number of improvements in the projects' requirements ranging from clearer sentence structure to more complete requirements.