Application programming interfaces (APIs) documentation is the official reference of the APIs. Defects in API documentation pose serious hurdles to their comprehension and usage. In this paper, we present DRONE, a tool that can automatically detect the directive defects in APIs documents and recommend repair solutions to fix them. Particularly, DRONE focuses on four defect types related to parameter usage constraints. To achieve this, DRONE leverages techniques from static program analysis, natural language processing and logic reasoning. The implementation is based on the Eclipse-plugin architecture, which provides an integrated user interface. Extensive experiments demonstrate the efficacy of the tool.