Jr-Arch is an open-source coding agent built to live inside your repository. Bring your own model and API key instead of being locked to a single provider. Agents, rules, personas, and guardrails are plain files in `.gitagent/`, making them readable, version-controlled, and reviewable. Built around the OpenGAP protocol, with support for major model providers and OpenAI-compatible endpoints, zero runtime dependencies, and no telemetry.