Trae Agent is an open-source LLM-based software engineering agent by ByteDance that provides a powerful CLI interface for executing complex development tasks through natural language instructions. Built in Python 3.12+, it features a transparent, modular architecture designed for both production use and research into agent behavior. The project supports multi-LLM providers including OpenAI, Anthropic, Google Gemini, OpenRouter, Doubao, Azure, and local Ollama models. Key capabilities include Lakeview summarization for concise step-by-step execution summaries, trajectory logging for detailed analysis of agent decisions, Docker integration for containerized task execution, and MCP (Model Context Protocol) support. Its research-oriented design enables ablation studies and novel capability development, backed by a technical report on test-time scaling approaches (arXiv:2507.23370).