Hey! Wanted to share OpenHarness: a code-first, composable SDK to build agent harnesses like Claude Code in no time, built with the AI SDK.
It provides a set of composable primitives, like an agent, session, and a basic set of tools. The session handles turns, retries, hooks, context management, etc., and the agent class supports AGENTS.md, agent skills, MCP servers, subagents, etc.
There are a few examples in the repo, including a Next.js full-stack application. I believe this is currently the easiest way to build a Claude Code-style app.
Would love to get your feedback on this!
Repo: GitHub - MaxGfeller/open-harness: A code-first, composable SDK to build powerful AI agents · GitHub
Max
