Diag Harness

Diag Harness is a Quality skill for Claude Code, published by ruvnet in metaharness.

609 stars72 forkson ruvnet/metaharnessAdded 2026/08/25+2% in starsRepository updated 2026/08/24

agent-harnessagent-harness-generatoragent-scaffoldingagentic-aiagentic-frameworkautonomous-agentsclaude-codecodexcreate-agent-harnesshermes-agentmcpmcp-servermulti-agentopenai-codexopenclawpi-devrvmsandboxingscaffoldscaffolding

Install in seconds

Install Diag Harness

Copy Diag Harness into your Claude Code skills folder. Run the command in your terminal, or review the source on GitHub before installing.

terminal

npx degit https://github.com/ruvnet/metaharness/tree/main/.claude-plugin/skills/diag-harness ~/.claude/skills/diag-harness

Requires Node.js. Downloads this skill only — not the rest of the repository — into your Claude Code skills folder.

Without Node.js

git clone https://github.com/ruvnet/metaharness.git

Clones the whole repository, then copy the skill’s own directory into your skills folder yourself.

In this catalog

Source file: .claude-plugin/skills/diag-harness/SKILL.md in ruvnet/metaharness
Installs to: ~/.claude/skills/diag-harness
Collection: One of 16 skills cataloged from this repository
Category: Quality — 1354 skills

What Diag Harness does

Diag Harness checks whether a scaffolded harness matches the installed `@metaharness/kernel` version and reports the skew verdict. Use it before other harness commands or when compatibility errors appear.

Diag Harness is cataloged under Quality on DirSkills. Diag Harness comes from a repository tagged agent-harness, agent-harness-generator, agent-scaffolding, agentic-ai and agentic-framework.

Documentation

README

Excerpt

diag-harness

Codex skill: kernel-version skew check for a scaffolded harness — the ADR-027 diagnostic UX loop.

What it does

Single-question check: does my local @metaharness/kernel match what this harness was scaffolded against? That's the cross-machine compatibility question almost every "this harness doesn't work" support ticket turns out to be.

Reads .harness/manifest.json:

Field	Source	Meaning
`meta.surface`	iter 56	Which surface produced the harness (`cli` or `web-ui`)
`meta.kernel_version`	iter 58	The `@metaharness/kernel` version stamped at scaffold time

This is the opening of the README. Read the full README on GitHub.

Commands Diag Harness provides

Slash commands named in this skill’s SKILL.md, listed in the order they first appear.

/diag-harness

Frequently asked about Diag Harness

What else does ruvnet publish alongside Diag Harness?
Diag Harness is one of 16 skills that DirSkills catalogs from ruvnet/metaharness, the repository it ships in. Its siblings there include Compare Harnesses, Create Harness and Darwin Mode. Each one is a separate skill with its own page in this directory, installs the same way Diag Harness does, and is maintained by ruvnet in that same repository. The rest of the collection is listed on the ruvnet/metaharness page.
How does Diag Harness compare to other Quality skills?
Diag Harness ranks #1122 by stars among the 1354 Quality skills in this catalog. The most-starred ones next to it are Benchmark, Benchmark Optimization Loop and API Design Patterns. DirSkills ranks by the star count of the repository each skill ships in, so that order reflects how popular those repositories are rather than any review of Diag Harness against them. Open each page to compare what they document and how they install.