Open Source Rust Agent Harnesses

Claw Code is an open-source AI agent harness project focused on building better tools for orchestrating and managing autonomous coding agents. It originated as a clean-room reimplementation inspired by the architecture of Claude Code, aiming to replicate core concepts without using proprietary code. The project provides a Python-based foundation for experimenting with agent workflows, tool integration, and task execution pipelines. It emphasizes harness engineering—how agents are structured, how they interact with tools, and how they maintain context during execution. The system is being actively expanded, with a Rust-based runtime in development to improve performance and memory safety. Overall, Claw Code serves as a research-driven platform for advancing agent-based software development systems.

Caprock is a free, open-source desktop app for AI coding agents, for macOS, Windows and Linux. It puts Claude Code, Codex and OpenCode sessions — including the ones you start in your own terminal — and the Gemini CLI sessions it starts into one window: terminals and projects in tabs and split panes, with activity, cost, plan limits and loop alerts for every session. Cost is per repository and per model, priced at API list prices from the tokens the agents already record, next to the 5-hour and weekly plan-limit windows. Everything the agent wrote is searchable across sessions and kept after Claude Code's 30-day transcript cleanup. A phone can carry on the work. It works with the subscription you already have. A daemon on loopback records sessions into a local SQLite database: no account, no hosted service, no telemetry. Free under Apache-2.0; an optional Premium licence adds paid features on top.