Loopgate Harness (py_ralph_frame) is an open-source Python verification harness and orchestrator developed by rxdt. It is built to enforce deterministic quality gates and testing boundaries around both headless CLI coding agents and interactive development agents working within a codebase. In daily use, the harness integrates into local Git workflows via dedicated Git hooks and terminal commands such as 'harness init' and 'configure-agents'. When an agent generates code, Loopgate intercepts and validates the changes by evaluating staged diff sizes and executing configured validation pipelines, including Ruff formatting, Ruff linting, Hypothesis property-based tests, and Mutmut mutation testing. Loopgate differentiates itself from standard agent execution runners by focusing specifically on strict quality enforcement and mutation scoring. It prevents automated agents from introducing silent regressions or out-of-scope edits by maintaining a strict configuration hierarchy across standalone config files, pyproject.toml, tox.ini, and setup.cfg. Loopgate is free and open-source software built for Python 3.10 through 3.14 environments and is currently under active early-stage development.
Tags: agent harness, ai agent, cli, coding agent, developer tools