agent-harness

Agent Harness Skill

Agent Skill for bootstrapping, verifying, and enforcing agent-harness infrastructure in repositories. Makes repos agent-ready with self-sustaining enforcement mechanisms that work for all contributors -- human or AI, with or without skills installed.

What is Agent Harness?

Agent harness is repo-level infrastructure that makes AI coding agents reliable. Instead of relying on individual skill installations, the harness embeds enforcement directly into the project via CI workflows, git hooks, and conventions.

The skill follows the "verify-first" principle: it primarily checks consistency, secondarily creates missing artefacts, and delegates specialised work to existing skills.

Key concepts:

• AGENTS.md as compact index (<150 lines), not encyclopedia
• Three enforcement layers: hard (CI/branch protection), automatic (.envrc/hooks), soft (conventions)
• Three maturity levels: Basic, Verified, Enforced
• The skill is the installer; the harness enforces itself

Installation

Claude Code Marketplace

/plugin marketplace add netresearch/claude-code-marketplace

Composer

composer require netresearch/agent-harness-skill

npm (Node Projects)

npm install --save-dev \
  @netresearch/agent-skill-coordinator \
  github:netresearch/agent-harness-skill

Requires @netresearch/agent-skill-coordinator, which discovers the skill in node_modules and registers it in AGENTS.md via a postinstall hook. For pnpm, also allowlist the coordinator's postinstall:

{
  "pnpm": {
    "onlyBuiltDependencies": ["@netresearch/agent-skill-coordinator"]
  }
}

npx (skills.sh)

npx skills add https://github.com/netresearch/agent-harness-skill

Git Clone

git clone https://github.com/netresearch/agent-harness-skill.git

Usage

Verify (Primary Mode)

Check harness consistency in the current repo:

"Verify the harness in this repo" "Check if this repo is agent-ready" "Run harness verification"

Bootstrap

Create missing harness artefacts:

"Make this repo agent-ready" "Bootstrap the harness for this project"

Audit

Check maturity level:

"What's the harness maturity of this repo?" "Audit agent-readiness"

CLI (without skill)

The verification script works standalone:

# Full check
bash scripts/verify-harness.sh --format=text

# Check specific level
bash scripts/verify-harness.sh --level=2

# Status summary
bash scripts/verify-harness.sh --status

# In CI
bash scripts/verify-harness.sh  # auto-detects GitHub Actions format

Maturity Levels

Level 1 -- Basic

• AGENTS.md exists and is index-format
• Commands documented
• docs/ directory exists

Level 2 -- Verified

• All AGENTS.md references resolve
• Documented commands match actual targets
• docs/ARCHITECTURE.md exists
• CI harness verification active

Level 3 -- Enforced

• harness-verify is a required check
• Git hooks auto-activate on clone
• PR template includes harness checklist
• Drift detection active

See maturity-levels.md for details.

Enforcement Mechanisms

The skill sets up enforcement that works for ALL contributors:

Mechanism	Layer	Works without skill?
CI Workflow	Hard	Yes -- runs on GitHub
Branch Protection	Hard	Yes -- GitHub server-side
.envrc (direnv)	Automatic	Yes -- in repo
composer/npm hooks	Automatic	Yes -- runs on install
Git hooks	Automatic	Yes -- in repo
AGENTS.md	Soft	Yes -- agents read it
PR Template	Soft	Yes -- GitHub shows it
Makefile targets	Soft	Yes -- in repo

See enforcement-mechanisms.md for details.

Integration with Other Skills

The harness skill delegates specialised work: