OpenHarness is an open-source terminal coding agent and execution harness developed by Zhijie Wong. Built as an open alternative designed to achieve parity with tools like Claude Code, OpenHarness provides both an interactive terminal interface (`oh`) and programmatic interfaces for driving autonomous coding workflows. In daily use, developers interact with OpenHarness via the `oh` command-line executable or integrate it into automated pipelines through dedicated Python and TypeScript SDKs. The tool executes multi-turn programming tasks by streaming typed event payloads—such as text deltas, tool executions, cost metrics, and session states—over an NDJSON event protocol. OpenHarness distinguishes itself by offering dual-layer integration: it provides an in-process SDK and a subprocess-driven client SDK, along with support for the Agent Client Protocol (ACP) server specifications. This architecture allows developers to run standalone CLI coding sessions or embed the harness directly into larger toolchains with structured event streaming and hook decisions. OpenHarness is open-source software available under GitHub, providing a self-hostable harness without proprietary licensing fees, though users supply their own model backend access.
Tags: agent harness, cli, coding agent, OpenSource, terminal