ArcKit Plugin for Claude Code

The Enterprise Architecture Governance Harness — a Claude Code plugin providing 75 slash commands across strategy, architecture, delivery, assurance, and interoperability.

Installation

Step 0: Make sure Claude Code is up to date

ArcKit needs Claude Code v2.1.280 or later (see Prerequisites below). The simplest way to land on a supported version — even if you've never installed Claude Code before — is:

claude install latest

If you don't yet have the claude CLI on your PATH, follow the official Claude Code install guide first, then run claude install latest. To check what you're on:

claude --version

Step 1: Add the marketplace

In Claude Code, run:

/plugin marketplace add tractorjuice/arckit-claude

Step 2: Install the plugin

/plugin

Go to the Discover tab, find arckit, and install it. Or via CLI:

claude plugin install arckit@arckit-claude

Installing with ArcKit overlay plugins

The same marketplace hosts the core plugin plus regional, sector, and tooling overlays.
Install only the plugins you need:

claude plugin install arckit arckit-uae
claude plugin install arckit arckit-au arckit-au-energy
claude plugin install arckit arckit-uk-finance

The arckit-uk-gcloud overlay is public for installation and inspection, but remains
proprietary and is not MIT licensed.

Alternative: Load for a single session

claude --plugin-dir /path/to/arckit-claude

Prerequisites

• Claude Code v2.1.280 or later (recommended minimum)
• Bash shell (for helper scripts)
• For /arckit:aws-research: AWS Knowledge MCP server (included)
• For /arckit:azure-research: Microsoft Learn MCP server (included)
• For /arckit:gcp-research: Google Developer Knowledge MCP (requires GOOGLE_API_KEY — see MCP Servers)

Why v2.1.280? v2.1.280 adds Claude Opus 5.5 (claude-opus-5-5), the default Opus model. Opus 5.5 always thinks, so ArcKit's effort: max commands can no longer be quietly sent as high by a session with thinking off, and the Effective Effort row in each artefact's Build Provenance is accurate. The floor carries v2.1.251, which stops the file tools following a symlink swapped inside the working directory after the permission check, and makes Grep and Glob honour Read() deny rules through symlinked paths — the class of bypass ArcKit's file-protection and secret-file-scanner gates sit in front of. It also sends Opus 5 effort: xhigh/max as high when thinking is off instead of failing, so ArcKit's effort: max commands complete on thinking-off sessions. v2.1.246 fixed four plugin-loading bugs that hit ArcKit's exact layout: /reload-plugins counted 0 skills for skills/*/SKILL.md plugins, hook errors showed a literal ${CLAUDE_PLUGIN_ROOT}, the plugin cache created duplicate SHA-named directories, and claude plugin update <bare-name> failed. The floor carries forward v2.1.234, which stops Claude Code's MCP diagnostics printing resolved secrets — ArcKit bundles two keyed MCP servers whose ${user_config.*} API keys sit in request headers, and on a keyless session those connections fail by design, so ArcKit routinely produces exactly the diagnostics this fixed. v2.1.221 fixed WebSearch returning a 400 at effort: xhigh/max with thinking disabled, which silently broke ArcKit's effort: max commands and research agents for anyone running with thinking off. v2.1.222-v2.1.224 close PreToolUse auto-allow bypasses in background agent tasks (load-bearing since v2.1.232 made spawns background by default), Bash permission-check bypasses, and a sandbox deny-path bypass. It also carries v2.1.219's Claude Opus 5 (claude-opus-5) with 1M context and fast mode (superseded as the default by Opus 5.5); v2.1.200's project-scoped plugin loading from git worktrees and claude agents --plugin-dir <dir> visibility; the v2.1.198-v2.1.199 background-subagent reliability, parent error-propagation, and hook stderr-visibility fixes; v2.1.197's Claude Sonnet 5 default with native 1M context; and v2.1.172's wildcard-domain WebFetch fix. It also carries the older MCP alwaysLoad, provenance hook, release validation, telemetry, /context, Auto mode, plugin update, MCP leak, retry, and subagent working-directory fixes ArcKit relies on.

Quick Start

After installing the plugin:

1. Initialize a project (optional - commands will create structure automatically):

   /arckit:init
   

2. Create architecture principles:

   /arckit:principles
   

3. Create requirements for a project:

   /arckit:requirements NHS appointment booking system
   

What's Included

Hooks

Automation hooks run automatically to provide context and enforce standards. See the Hooks Guide for full details. docs/ENFORCEMENT.md states which rules the hooks enforce in code, which are only asked of the model, and what your organisation supplies.

OKF Interoperability

• /arckit:export-okf exports ArcKit ARC-*.md artifacts as copied Markdown with OKF-compatible frontmatter.
• /arckit:import-okf scans OKF Markdown bundles, writes .arckit/tmp/okf-import-report.json, and materializes safe imports as RSCH review notes.
• Source ARC frontmatter stamping is opt-in via ARCKIT_OKF_FRONTMATTER=1 or .arckit/config.json with { "okfFrontmatter": true }.

Template Customization

ArcKit templates can be customized per-project to match your organization's requirements, branding, or compliance frameworks.

How It Works

1. User templates override plugin templates: If a template exists in .arckit/templates/, it takes precedence over the plugin's default template.

2. Copy and customize: Use /arckit:customize to copy templates to your project for editing.

Quick Start

# List available templates
/arckit:customize list

# Copy a template to customize
/arckit:customize requirements

# Copy all templates
/arckit:customize all

Common Customizations

For non-UK Government projects:

• Remove "UK Government Alignment" sections
• Change classification scheme from OFFICIAL-SENSITIVE to your organization's scheme
• Remove TCoP, GDS Service Standard references

For your organization:

• Add custom Document Control fields (Cost Centre, Programme, Department)
• Change requirement ID prefixes (BR/FR/NFR → your taxonomy)
• Add organization branding and headers
• Modify compliance frameworks (ISO27001, SOX, HIPAA instead of UK Gov)

Template Location

project-root/
├── .arckit/
│   └── templates/              # Your customized templates
│       ├── requirements-template.md
│       ├── risk-register-template.md
│       └── ...
└── projects/
    └── ...

Keeping Templates Updated

When ArcKit plugin updates with new features:

• Your customized templates are not automatically updated
• Compare your templates with plugin versions periodically
• Merge new sections you want to adopt

Skills

The plugin includes conversational skills that activate automatically when you ask relevant questions:

• Wardley Mapping — Ask about evolution stages, doctrine maturity, build vs. buy decisions, gameplay patterns, or create interactive maps. For formal documents, use /arckit:wardley instead.

Commands Overview

Core Governance

• /arckit:principles - Create architecture principles
• /arckit:stakeholders - Analyze stakeholders and goals
• /arckit:requirements - Generate comprehensive requirements
• /arckit:risk - Create risk register (Orange Book)
• /arckit:sobc - Strategic Outline Business Case (Green Book)

Technical Design

• /arckit:data-model - Data model with GDPR compliance
• /arckit:diagram - Architecture diagrams (Mermaid)
• /arckit:wardley - Wardley Maps for strategy
• /arckit:adr - Architecture Decision Records

Research & Procurement

• /arckit:research - Technology market research
• /arckit:aws-research - AWS service research (MCP)
• /arckit:azure-research - Azure service research (MCP)
• /arckit:datascout - External data source discovery
• /arckit:evaluate - Vendor evaluation framework
• /arckit:sow - Statement of Work / RFP
• /arckit:gcloud-search - G-Cloud marketplace search
• /arckit:dos - Digital Outcomes & Specialists

UK Government Compliance

• /arckit:tcop - Technology Code of Practice review
• /arckit:secure - Secure by Design assessment
• /arckit:dpia - Data Protection Impact Assessment
• /arckit:ai-playbook - AI Playbook compliance
• /arckit:service-assessment - GDS Service Standard

Operations & Delivery

• /arckit:devops - DevOps strategy
• /arckit:finops - FinOps cloud cost management
• /arckit:mlops - MLOps strategy
• /arckit:operationalize - Operational readiness
• /arckit:backlog - Product backlog generation
• /arckit:roadmap - Architecture roadmap

See the full command list with /help arckit.

Project Structure

ArcKit creates this structure in your project:

projects/
├── 000-global/           # Cross-project artifacts
│   ├── policies/         # Organization policies
│   └── ARC-000-PRIN-*.md # Architecture principles
└── 001-project-name/     # Project artifacts
    ├── ARC-001-REQ-*.md  # Requirements
    ├── ARC-001-STKE-*.md # Stakeholders
    ├── vendors/          # Vendor evaluations
    └── external/         # External documents

MCP Servers

The plugin includes 5 MCP (Model Context Protocol) servers for cloud and government research:

AWS Knowledge and Microsoft Learn work out of the box with no configuration. The Google and Data Commons servers require API keys — if you don't set them, you'll see errors in the plugin UI, but all other commands work normally.

Setting up optional API keys

Google Developer Knowledge (for /arckit:gcp-research):

1. Get a free API key from Google AI Studio
2. Set the environment variable: export GOOGLE_API_KEY="your-key-here"

Data Commons (for data statistics lookups):

1. Get an API key from datacommons.org
2. Set the environment variable: export DATA_COMMONS_API_KEY="your-key-here"

Migration from CLI

If you previously used arckit init --ai claude:

# Remove CLI-generated files (plugin replaces them)
rm -rf .claude/commands/arckit.*.md
rm -rf .claude/agents/arckit-*.md
rm -rf .arckit/templates/
rm -rf .arckit/scripts/

# Keep your project data
# projects/ directory stays (user data)

Note: The ArcKit CLI no longer distributes Claude Code commands. Claude Code users should use this plugin instead.

For Gemini/Codex Users

This plugin is for Claude Code. For other AI assistants:

• Gemini CLI: Install the ArcKit Gemini extension (gemini extensions install https://github.com/tractorjuice/arckit-gemini)
• Codex CLI: Install the ArcKit CLI (pip install arckit-cli && arckit init --ai codex)

Links

• Repository
• Documentation
• Changelog

License

MIT