GUO is built with AI coding agents working alongside people. Every agent and every person follows the same rules, skills and checks. Using an agent is optional; the repository works the same without one.

Tool	Reads	Skills
Claude Code	CLAUDE.md, which imports AGENTS.md	.claude/skills/
Codex	AGENTS.md	.agents/skills/: run launchers\dev\agent_skills.bat once per checkout
GitHub Copilot	AGENTS.md	.claude/skills/
Cursor	AGENTS.md	.claude/skills/

AGENTS.md holds the project's instructions: the porting model, the rules, the commands and the roles. Change rules there, not in a tool-specific file.

A skill is a folder with a SKILL.md: a name, a description that says when to use it, and the steps to follow. It's the open Agent Skills format, so one copy serves every tool. Some you'll use most:

Skill	Does
port-status	Measures port progress: the audit, upstream drift, the client data.
port-file	Ports one upstream file or subsystem by its tier, builds it and re-measures.
parity-check	Compares GUO's frame against the reference renderer, pixel by pixel.
android-build	Doctor, export, install and smoke on the attached device.
uo-data	Authors new art, gumps or animations into a staged data set and proves them in game.
uo-multi, uo-decorate	Build and furnish new multis (Building Multis).
editor-smoke	Proves the editor add-on panel by panel.

The rest come from Claude Code Game Studios (MIT): design, QA, release and production workflows. launchers\dev\agent_skills.bat --check validates every skill's name and description.

.claude/agents/<name>.md each define one specialist. In Claude Code they run as subagents. In other tools, read the role's file when the work falls in its area. The port-specific roles:

Role	Owns
uo-port-strategist	What gets ported next, tier arbitration, the plan
fna-migration-specialist	The mechanical verbatim/shim bulk, and GUO.Compat
uo-fileformat-engineer	.mul/.uop readers, loaders, the decode cache
uo-network-engineer	Packets, handshake, encryption, compression
uo-render-engineer	The renderer, hues, input and audio (rewrite tier)
mobile-web-engineer	Android, web, touch, and their CI
uo-editor-engineer	The editor add-on and the world tools
uo-multi-architect	Authoring new multis

The same rules as people (Contributing), plus:

• Never edit sources/. The upstream reference is read-only.
• Measure, don't estimate. Progress claims come from the audit. "Ported" isn't "working": say whether there's a smoke test or a screenshot.
• No game data, credentials or machine paths in anything committed. CI and the pre-push hook check this.
• Scripted runs never take focus, so an agent can run the client while a person uses the machine.
• A person reviews and merges. Agents work on branches; nothing they make goes to main without passing the same checks as any change.

tools/guoasset is an MCP server that renders UO art with upstream's own loaders, as the parity reference. Any MCP-capable agent can use it; see its README.