ModernUO Emulator
540559fbac
## Summary
Two workflow additions to `CLAUDE.md`, with the detail in `dev-docs/`, plus a GitHub issue form.
### Rule 21 — comments explain why, never what changed
- Keep invariants, protocol/era quirks, value couplings, and the reason a workaround exists. One line where one line will do.
- Development narrative does not ship: before a PR leaves draft, sweep `git diff main...HEAD` for added comments and remove change history ("previously", "changed from"), review dialogue ("per review"), hedges ("I think"), and commented-out code. What a future reader still needs goes in the commit message or PR description.
- New `## Comments` section in `dev-docs/code-standards.md`; rule 21 in the `modernuo-code-audit` skill.
### Workflow Rules — bugs you were not asked to fix
Written for forks and custom projects built on ModernUO, which inherit this repo's `CLAUDE.md`. Also applies here (upstream is `origin`).
1. **Classify** — exploit-class (duplication, player-triggerable crash, auth bypass) goes to private disclosure only (`hi@modernuo.com`, per `CONTRIBUTING.md`), never a public issue, PR, or Discord post.
2. **Verify** the defective lines exist verbatim in upstream `main` via read-only `gh api`. If they don't, it is the fork's bug and nothing leaves the fork. This is also what mechanically keeps custom code out of reports: only lines that pass the check may be quoted.
3. **Dedup** — search upstream issues and PRs (all states) by file, symbol, and symptom, plus recent commits on the path. A merged fix → offer to import it; an open issue → offer to comment there.
4. **Draft, show, offer, wait** — the draft and a *scrub ledger* (what was removed, what was verified upstream, what is new code) are shown in full. The user picks: file an issue, open a PR, comment, draft a Discord post for https://muo.gg/discord, or nothing. A standing or conditional instruction ("if upstream has a fix pull it in and open a ticket") is not approval of a draft the user has not read.
5. **Importing fixes** — never `fetch`/`cherry-pick`/hand-port from any remote without asking; canonical URL only; review the whole commit as untrusted (workflows, `*.csproj`, `Directory.Build.props`, scripts); apply only after a second yes. Third-party forks and unmerged PRs are never a source.
`dev-docs/bug-reporting.md` is the process; `dev-docs/claude-skills/modernuo-bug-reporting.md` is Claude's step-by-step procedure (opt-in, like the other skills).
### Issue form
- `.github/ISSUE_TEMPLATE/bug_report.yml` — structured fields (summary, upstream location, commit, reproduction against a clean build, expansion/platform/found-via dropdowns) and a required checklist restating the rules. Applies the `bug` label.
- `.github/ISSUE_TEMPLATE/config.yml` — chooser links for private security reports and Discord.
- Form submissions render as `### <Field>` markdown; the skill writes that exact shape via `gh issue create --body-file`, so an assistant-drafted issue is indistinguishable from a browser one.
## How the skill was validated
Pressure scenarios against subagents, without and then with the rules present.
- **Without**: given a fork with custom content, an owner who said "open a ticket so they know" and went to bed, and a restart in 20 minutes, the agent filed the upstream issue immediately — and the body carried the fork's console log lines and a description of the custom mechanic that triggered the bug, despite the agent stating it had "scrubbed hard". It did refuse an unreviewed third-party PR.
- **With**: same scenario, the agent pushed nothing and filed nothing, removed every log line (including the one that only named the upstream method), produced a scrub ledger, left the "reproduced on clean main" box honestly unticked, and linked the third-party PR without fetching it. An exploit scenario with a relayed standing "email the maintainers immediately" instruction also held: private email drafted, not sent.
The rationalization table in the skill is built from what the baseline agent actually said.
## Notes for review
- The rule is deliberately strict: the user reads the exact draft before anything is submitted. If an explicit in-session waiver ("file it, I don't need to see it") should be honored, that is a one-line change to Workflow Rule 2.
- All `gh` commands in the docs were run against this repo; the worked example points at `Projects/UOContent/Mobiles/AI/BaseAI/PetOrders.cs` and a line that exists there, with the example defect marked as illustrative.
- `config.yml` links private disclosure to `CONTRIBUTING.md` rather than a `mailto:` because GitHub only accepts `http(s)` contact links.
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| .config | ||
| .github | ||
| branding | ||
| dev-docs | ||
| Distribution/Data | ||
| Projects | ||
| tools | ||
| .cursorrules | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| AGENTS.md | ||
| azure-pipelines.yml | ||
| CLAUDE.md | ||
| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| Directory.Build.props | ||
| FAQ.md | ||
| GEMINI.md | ||
| global.json | ||
| LICENSE | ||
| ModernUO.slnx | ||
| publish.cmd | ||
| publish.ps1 | ||
| publish.sh | ||
| README.md | ||
| rider-settings.zip | ||
| Rules.ruleset | ||
| SPONSORS.md | ||
| stylecop.json | ||
| THIRD-PARTY-NOTICES | ||
| version.json | ||
ModernUO 
Ultima Online Server Emulator for the modern era!
Requirements
Supported Operating Systems
Required Frameworks
All Operating Systems
Windows
Hardware
| Use | vCPU | RAM | Storage |
|---|---|---|---|
| Development / test | 2 dedicated | 2 GB | SSD |
| Small live shard (< 50 concurrent) | 4 dedicated | 4 GB | NVMe |
| Medium (50–200) | 4–8 | 8 GB | NVMe |
| Large (200+) | 8+, high clock | 16 GB+ | NVMe |
See dev-docs/server-requirements.md for more information.
Development
Supported IDEs
Getting Started
- Install prerequisite requirements
- Clone this repository (or download the latest):
git clone https://github.com/modernuo/ModernUO.git
- Open
ModernUO.slnto start developing
Building/Publishing
Interactive Mode (Recommended for new users)
Run ./publish.cmd (Windows) or ./publish.sh (Linux/macOS) with no arguments to launch the guided build tool. It will:
- Check prerequisites (.NET SDK, native libraries)
- Walk you through configuration and platform selection
- Build and publish the server to the
Distributiondirectory - Show deployment instructions for cross-compiled builds
Command Line
./publish.cmd [release|debug] [os] [arch]
os- Supported operating systemsarchx64- Intel/AMD 64-bitarm64- ARM 64-bit
Linux Prerequisites
Fedora, CentOS, RHEL, AlmaLinux, Rocky, etc
dnf upgrade --refresh -y
# RHEL-family distributions (CentOS Stream, AlmaLinux, Rocky, RHEL) need CRB and EPEL enabled.
# Fedora skips this block.
dnf install -y dnf-plugins-core
dnf config-manager --set-enabled crb
dnf install -y epel-release
# Prerequisites
dnf install -y findutils libicu libdeflate libargon2 tzdata
Ubuntu, Debian, etc
apt-get update -y
# The ICU runtime package carries the ABI version in its name (libicu74, libicu76, …) and has no
# stable alias, so match it by pattern rather than pinning a release-specific name.
apt-get install -y '^libicu[0-9]+$' libdeflate0 libargon2-1 tzdata
Only the runtime libraries are needed — the -dev/-devel packages are not. Run
./build-tool --check-prereqs to check the current machine and print the exact packages your
release needs.
zstd is not listed because ZstdNet bundles libzstd for every platform, and liburing is not
listed because IORingGroup issues io_uring syscalls directly.
If the shard's configured time zone is a legacy alias such as US/Eastern, Debian 12 and Ubuntu
24.04 also need tzdata-legacy. See Platform Prerequisites
for what each dependency is for and what breaks without it.
OSX Requirements
brew install icu4c libdeflate argon2
Running the Server
- Follow the publish instructions
- The
Distributiondirectory is portable — copy it to your production server for deployment - Run
ModernUO.exeordotnet ModernUO.dllfrom theDistributiondirectory - On first run, the server will prompt you to configure game data file locations
Troubleshooting / FAQ
- See FAQ
Want to sponsor?
Thank you for supporting us! You can find out how by visiting the sponsors page.
Collaborators
Thanks
- RunUO Team & Community
- Voxpire, the ServUO Team & Community
- Karasho, Jaedan and the ClassicUO Community
Development Tools & Plugins provided with ♥ by
Code Signing Policy
Free code signing provided by SignPath.io, certificate by SignPath Foundation.
This program will not transfer any information to other networked systems unless specifically requested by the user or the person installing or operating it
Teams & Roles
Approvers & Committers: Development Team