FaciesTool is a lightweight Python-based tool designed for interactive sedimentary facies mapping directly on Digital Outcrop Models generated in Agisoft Metashape. The tool operates entirely within the Metashape environment and enables geologists to assign and visualize sedimentary facies on three-dimensional photogrammetric models without exporting data to external software. FaciesTool provides an intuitive graphical user interface that allows users to define custom facies categories, assign RGB color codes, and apply these classifications directly to selected regions of the model using native Metashape selection tools. Facies assignments are performed by modifying vertex color attributes, ensuring immediate visual feedback while preserving the original geometry and texture of the model. Facies definitions and assignments can be saved and reloaded using JSON files, enabling reproducible interpretations and reuse across multiple projects. By avoiding model export and operating on the original mesh and vertex data, FaciesTool maintains full data fidelity and simplifies the interpretation workflow, particularly for complex outcrops with intricate stratigraphic architectures. The tool is intended for research and educational applications in sedimentology, stratigraphy, and digital outcrop analysis, and provides a flexible foundation for future extensions such as semi-automated classification, statistical analysis, or integration with geospatial modeling workflows.