Plandex

Plandex is a 'plan-first' terminal AI agent designed specifically for large-scale coding tasks that span dozens of files. It features a 2M token effective context window, 20M+ token indexing via Tree-sitter, support for 30+ languages, and context caching for OpenAI, Anthropic, and Google. The standout feature is its cumulative diff review sandbox — changes are accumulated and reviewed before being applied to your codebase, giving you full control over what gets modified.