Repository layout

What's in the repository today: the files at its root, every project and what it depends on, the tests and the CI workflow. The server core itself isn't built yet; its design is on Server core design, and the codec, its first piece, is on Codec design.

The root

Build and repository files

File	Holds
global.json	The SDK pin, 10.0.400 with rollForward: latestPatch, and Microsoft Testing Platform as the test runner
Directory.Build.props	Nullable reference types on for every project; every warning an error; code-style rules run in the build; the analysis level pinned to 10-recommended
Directory.Build.targets	The hot-path switch: a project that sets <HotPath>true</HotPath> gets the banned-API list and the hot-path rules as errors
Directory.Packages.props	Every package version, pinned exactly (central package management)
nuget.config	nuget.org as the only package source, mapped for every package
.editorconfig	Formatting, style and naming rules, and every suppression with its reason
.gitattributes	* text=auto eol=crlf: text stored with LF, checked out with CRLF on every system
.git-blame-ignore-revs	Mechanical commits git blame skips: the line-ending normalization, the formatting pass, the renames to the code standard, and the wire models' neutral rename
README.md, CONTRIBUTING.md, SECURITY.md, LICENSE	The front door, the contributor rules, how to report a security problem, the AGPL-3.0

Folders

Folder	Holds
Source/	Every project a server is built from, and the solution Source/NexusTomorrow.slnx
Tests/	One test project per project under test
Tools/	Tools for the repository itself: the protocol reference generator
Build/HotPath/	The hot-path ban list (BannedSymbols.txt) and the rules it raises to errors (HotPath.globalconfig)
.github/workflows/	The Tests workflow

Projects

Libraries

Every library targets net10.0, except the generator, which targets netstandard2.0 because the compiler loads it.

Project	Holds	References	Nullable
NexusTomorrow.Shared	Factories, configuration binding, the update timer, shared extensions		On
NexusTomorrow.Cryptography	SRP6 login maths, the packet cipher, password and random helpers		On
NexusTomorrow.IO	Readers for the client's area files; reader and writer for the server's map format, .nfmap		On
NexusTomorrow.Game.Static	The game's enums and flags, one folder per system		On
NexusTomorrow.GameTable	Typed loading of the client's game tables (.tbl) and text tables	Game.Static, Shared	On
NexusTomorrow.Network.Codec	The bit reader and writer, the declaration attributes, the layout types and the layout tree with its text form, and the client facts table. Hot path		On
NexusTomorrow.Network.Codec.Generator	The source generator that writes each declared type's reader, writer and layout, and its diagnostics NTC001 to NTC013		On
NexusTomorrow.Network	The opcode list, exactly the client's 1,119 wire opcodes; the [WireMessage] attribute, and [Verified] with its Rung; the three messages both the auth and world servers use, ServerHello (0x0003), ClientEnvelope (0x0244) and NestedMessage (0x025C); NetworkGuid; and the network configuration	Network.Codec, Shared; the generator	On
NexusTomorrow.Network.Sts	Message models for the STS login protocol, in XML		On
NexusTomorrow.Network.Auth	Message declarations for the auth server; the generated reader and writer are their only code	Game.Static, Network; the generator	On
NexusTomorrow.Network.World	Message declarations for the world server; the generated reader and writer are their only code	Game.Static, Network; the generator	On

Every project builds with the analysers on, nullable reference types on and every warning as an error, and none opts out of any of them. Network, Network.Auth and Network.World run the generator, which writes each model's reader, writer and size, and one WireMessages registry per assembly with a factory per direction keyed by opcode. Nothing else in the tree reads or writes a message. The three also write their XML documentation, which the verification check reads.

Tools

Project	Does	References
NexusTomorrow.MapGenerator	Extracts the game tables and localization files from your client, and generates .nfmap map files from its area files	GameTable, IO, Shared
NexusTomorrow.ClientConnector	Starts your client with a server's address on its command line. Windows only	Shared

How to run them is in the repository's README.md. Their output is built from your client and never goes in the repository.

One more sits under Tools/, since it serves the repository rather than a server:

Project	Does	References
NexusTomorrow.ProtocolReference	Generates this wiki's message reference, an index by opcode and a page per area, from the declarations' generated registries and their XML documentation. It reads no client files	Network, Network.Auth, Network.World

Packages

Package	Used by
Microsoft.Extensions.* (configuration, dependency injection, logging, options)	Shared, Network, GameTable, MapGenerator, the tests
Microsoft.CodeAnalysis.CSharp, Microsoft.CodeAnalysis.Analyzers	The generator and its tests
Microsoft.CodeAnalysis.BannedApiAnalyzers	Every hot-path project, added by Directory.Build.targets
NLog	Shared
Newtonsoft.Json	GameTable, ClientConnector
CommandLineParser	MapGenerator
Nexus.Archive	MapGenerator, to read the client's archives
xunit.v3.mtp-v2, Microsoft.Testing.Extensions.TrxReport	The tests

Tests

Test projects

Project	Tests
NexusTomorrow.Network.Codec.Tests	The bit reader and writer against hand-derived bytes; strings and packed floats; generated code on test messages of every member shape; the facts check over every message Network, Network.Auth and Network.World declare, with each disagreement pinned; the verification check, which holds every declared message to its rung and the documentation it requires, with every message below Fields pinned; and the split gate, which fails a message at Fields that splits a value the client reads whole
NexusTomorrow.Network.Codec.Generator.Tests	Every diagnostic, and the source the generator emits
NexusTomorrow.Cryptography.Tests	The SRP6 session key is always 64 bytes
NexusTomorrow.GameTable.Tests	A missing or empty GameTablePath fails options validation, and a bound one passes
NexusTomorrow.ClientConnector.Tests	Reading the configuration throws, naming the key, when the host name or language is missing or empty, and returns both when they're set
NexusTomorrow.ProtocolReference.Tests	The pages on test messages against hand-written pages; an unverified message shown as layout only; the index in opcode order; areas taken from the model folders; pages written as UTF-8 without a byte order mark, with LF line ends; a regenerated set removing the message pages it no longer has and nothing else; and the walk, which turns every declared message into its page rows and requires them to reproduce its generated layout tree

318 tests in all, in six xUnit v3 test applications on Microsoft Testing Platform: 237 in the codec's, 64 in the generator's, 10 in the protocol reference's, and 7 in the other three. The facts check and the verification check, among the codec's tests, and the protocol reference's walk each cover every declared message.

The workflow

.github/workflows/test.yml, named Tests:

Step	Does
Trigger	workflow_dispatch only, with an optional args input passed to the test applications
Runner	ubuntu-24.04
Permissions	contents: read
Checkout	Full history, so the commit check can see every commit since main; the token isn't kept in the checkout
Commit messages	Every commit in origin/main..HEAD: a blank second line, a headline of 72 characters or fewer, no full stop at its end
Em dashes	Fails on any em dash in a .cs or .md file, and lists where
Method words	Fails on any word in a .cs or .md file, other than CONTRIBUTING.md, that says how a client fact was found, and lists where
Set up .NET	Installs the SDK global.json asks for: the latest 10.0.4xx patch
Restore, build	Against Source/NexusTomorrow.slnx, in Debug
Format	dotnet format Source/NexusTomorrow.slnx --verify-no-changes, after the build, because it loads the codec's generator from the build output
Test	Every test application, with a .trx report
Upload results	The test-results artifact, uploaded even when tests fail

Every action is pinned to a full commit. Running the tests shows how to dispatch it.

Known edges

• Every message, nested type and field carries a neutral name built from its opcode and position (Client009A, Unknown0) until it's checked against the client. The first two areas, pregame and world entry, have been, and their messages carry the names the check gave them. Pregame's sit in Message/Model/Pregame/ and the Network and Network.Auth model folders; world entry's sit in the world model root and its PlayerPath/ folder until the client's areas are settled. The verification check pins the 1,071 messages not yet read to their fields as unverified. The ones the old code never had sit in the world model folders by opcode range, a grouping that claims nothing.
• The facts check pins 43 disagreements with the client's full layouts, each with its reason. The message audit settles them as it checks each feature area.
• There's no message framing yet. The old code's framing was deleted with its packet layer, unused; framing comes back with the core skeleton's transport, built on the codec.
• MapGenerator and ClientConnector haven't been run against a real client since the nullable work changed how they read their settings.
• The old server's login front door, permissions and GM command definitions aren't here yet. They were part of the trunk that was deleted, and come back lifted from the old code when the core is ready for them.

Where the code lives

Piece	Path
The solution	Source/NexusTomorrow.slnx
Projects	Source/NexusTomorrow.*/
The codec	Source/NexusTomorrow.Network.Codec/
The generator	Source/NexusTomorrow.Network.Codec.Generator/
The client facts table	Source/NexusTomorrow.Network.Codec/Facts/wire-facts-16042.jsonl
The protocol reference generator	Tools/NexusTomorrow.ProtocolReference/
The hot-path switch and list	Directory.Build.targets, Build/HotPath/
Tests	Tests/NexusTomorrow.*.Tests/
Package versions	Directory.Packages.props
The workflow	.github/workflows/test.yml