Coding-Tutor is a programming tutoring tool based on a large language model (LLM), designed to help learners improve their programming skills through conversational interaction. It addresses key challenges in programming tutoring through a Trace-and-Verify (Traver) workflow that combines knowledge tracing and round-by-round verification. This tool is not only suitable for programming education but also extensible to other task tutoring scenarios, helping to adjust teaching content according to the learner's knowledge level. The project is open source and supports community contributions.