FaithC is a Python library (with CUDA acceleration) for near-lossless 3D mesh encoding and decoding using Faithful Contour Tokens (FCT), as accepted at CVPR 2026 (Oral). It implements an encoder that transforms a mesh into compact per-voxel tokens (anchors, normals, edge flux signs) via octree traversal, SAT-based triangle clipping, QEF optimization, and edge flux computation. The decoder reconstructs the mesh from tokens using edge-based quad extraction and triangulation. The library is not a standalone application but a research-oriented tool intended for downstream tasks like VAE and diffusion models. It provides both a modern class-based API (FCTEncoder/FCTDecoder) and an older functional API. The codebase is well-structured with modular components, custom CUDA kernels for performance, and a PyTorch-centric design. However, it has some maintenance risks including dual code paths, hardcoded CUDA dependencies, and a custom 'atom3d' package without version pinning.