Harness LibraryAn open library for agent harnesses.
Find a reusable starting point, understand its setup, and improve it for your task.
What this directory includes
An agent harness is the surrounding setup that lets an AI model act on a task. It can include instructions, skills, tools, environment mappings, checks and workflows. Harness Library focuses on reusable, task-specific setups: from a small skill folder to an MCP workflow or a larger harness package.
Each listing links to its source and focused distribution, explains installation and manual connections, and states the license and review scope. Component counts are optional.
Harnesses, skills and MCP servers
A skill can supply instructions; an MCP server can expose tools. A task-specific harness can combine those pieces with a workflow and checks. The library welcomes both compact skill-based setups and larger packaged workflows, as long as their scope is clear.
For background on the general term, see Anthropic’s agent evaluation glossary.
Review and attribution
“Setup reviewed” means the installation and distribution were examined. “Artifacts checked” refers to the specific evidence described on the page. Neither means every model or platform was tested.
Harneloop is optional. “Built with Harneloop” is a separate attribution for harnesses created or improved through Harneloop. The directory is not limited to that framework.
Who maintains it?
Maintained by Kristofer Jussmann (@Ker102). Source, changes, submission issues and review records are public in the Harness Library repository.
New submissions are welcome. We’re looking for practical harnesses people can actually install and use. See how to submit →
Common questions
Can I submit just a few skills?
Yes. A useful skill folder, MCP workflow or complete harness package can qualify. Explain the task, installation and manual setup clearly.
Do I need to use Harneloop?
No. Submissions can use any agent or framework. Built with Harneloop is an optional attribution, reviewed separately from the listing.
What if my repository contains a whole application?
Provide a focused package or a dedicated harness branch so users can install only the harness. Do not make them download unrelated videos, caches or application assets.
Does a listing mean it works with every model?
No. Each page states its review scope, evidence and manual prerequisites. Setup reviewed and artifacts checked are different claims; neither guarantees every platform or model.
Is submitting free?
Yes. Browsing and submitting to the directory are free. You need a GitHub account to open a submission issue; a Harness Library account is not required.