Plandex is an open-source terminal-based AI coding agent designed to handle complex, multi-file engineering tasks in large codebases. Created by Dane Schneider and the open-source community, Plandex orchestrates multi-step development workflows by breaking down prompts into structured execution plans across multiple files. In daily use, Plandex operates through a dedicated CLI interface backed by a client-server architecture. Developers add relevant project context, directories, files, or docs into an isolated context window, submit prompts, and let Plandex propose changes in a sandboxed plan. It supports multiple LLM providers (including Anthropic Claude and OpenAI) routed via a LiteLLM proxy integration, featuring automatic fallback mechanisms and streaming error handling. What distinguishes Plandex is its explicit branching, planning, and sandboxing architecture. Unlike agents that apply edits directly to the working directory, Plandex manages isolated plans with version control primitives, allowing engineers to review unified diffs, refine iterations, recover past iterations using reflog mechanics, and apply changes only when satisfied. Plandex is open source. While a hosted Plandex Cloud offering was previously available, the agent is designed to run self-hosted with local servers and user-provided API keys.
Tags: ai agent, cli, code assistant, coding agent, developer tools, OpenSource