hkHarness Kit
Concepts

Harness Protocol

Using a coding agent? Install the Harness Kit docs as a skill:
npx skills add https://github.com/harnessprotocol/harness-kit --skill harness-docs

Harness Protocol

The Harness Protocol is an open specification for portable AI coding harness configuration. It defines a vendor-neutral harness.yaml format, validated by JSON Schema, that captures the complete operational context for an AI coding agent: plugins, MCP servers, environment requirements, instructions, and permissions.

How harness-kit relates to it

harness-kit is the reference implementation of the Harness Protocol. The relationship mirrors MCP and Claude Desktop: the protocol is the open specification, and harness-kit is the first tool that implements it.

Conformance does not require harness-kit. Any tool that correctly validates and applies harness.yaml according to the specification is a conformant implementation.

Desktop App

The harness-kit desktop app treats harness.yaml as a first-class element. The Harness File page (the default landing page under the Harness section) reads ~/.claude/harness.yaml or ~/harness.yaml and displays a structured, annotated breakdown of each section — plugins, MCP servers, env declarations, instructions, permissions, and extends — with a raw YAML toggle.

  • Harness Protocol spec — full specification, including architecture, field reference, security model, and plugin manifest format
  • JSON Schema — machine-readable validation schema
  • harness-kit — reference implementation

Where harness-kit fits

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How It Works

harness-kit is three things — a config format, a desktop management console, and a CLI — plus a plugin system that delivers skills and agents to your AI coding tools.

On this page

Harness ProtocolHow harness-kit relates to itDesktop AppLinks