Reasonix

What is Reasonix?

Reasonix is an open-source AI coding agent engineered specifically for DeepSeek's byte-stable prefix cache, delivering dramatic cost savings and high performance in long coding sessions. Unlike traditional agents that pay full price for every growing prompt, Reasonix maintains an append-only history that keeps the prefix byte-identical, achieving over 90% cache hit rates on long sessions. This collapses input-token costs to roughly one-fifth of normal, making extended interactions economically viable. The agent runs as a single Go binary (CGO-free, cross-compiled for darwin/linux/windows on amd64/arm64) with no Node runtime required, ensuring minimal setup and maintenance. It provides three interfaces: a full-screen TUI with responsive localized footer, terminal-native text and image paste, and a local browser UI via `reasonix serve`. The engine supports stdio, SSE, and streamable HTTP, allowing external servers to merge their tools into a unified registry under a prefix. Built-in agents include explore, research, review, and security-review, plus Markdown skill scripts with isolated tools. A `/plan` command prompts the model to plan first, while permissions and workspace sandbox govern every tool call. Each request replays the exact same byte-for-byte prefix, so the model only computes new content, making long sessions cheaper per turn rather than more expensive. Reasonix maps the codebase once and keeps it cached, further optimizing performance. Use cases include continuous development, code review, security auditing, and research tasks where maintaining context over many turns is critical. Technical highlights: append-only history aligned to DeepSeek's prefix cache, 90%+ cache hit, input tokens billed at ~1/5, cross-platform binary, no external runtime dependencies, and extensible tool registry. One command installs on macOS, Linux, Windows, and WSL. MIT licensed.

Use Cases