The code that turns Mojang's unobfuscated Minecraft 26.x server jars into a generated Go library, with one branch per Minecraft version in the data and library repositories:

Mojang jar ──► data-gen/ ──┬─► mc26-data      (releases)                ──► gen/ ──► go-mc26     (the library, one branch per version)
                           └─► mc26-data-pre  (snapshots, pre-releases)              ◄── go-mc26-kit (bot, server, accounts, examples: tested against every build)

Requirements: Go and podman or docker — the extractors and the vanilla test server both run in eclipse-temurin:25-jdk (--runtime host runs the server on the host's Java 25 instead). Everything below writes only under temp/.

go run ./gen/cmd/mc26 pipeline --version 26.2 --smoke --e2e   # extract → build → vet/test → smoke → example bots
go run ./gen/cmd/mc26 extract  --version 26.2           # only the JSON: temp/data/26.2 (+ _meta.json)
go run ./gen/cmd/mc26 build    --data 26.2              # the library: temp/lib/26.2, and the kit against it: temp/kit/26.2
go run ./gen/cmd/mc26 smoke    --version 26.2           # the kit's bot and the library's management client against a vanilla server
go run ./gen/cmd/mc26 e2e      --version 26.2           # the kit's example bots against a vanilla server
go run ./gen/cmd/mc26 fixtures --version 26.2           # the save tests' small world, cut from what e2e left
go run ./gen/cmd/mc26 crosscheck --version 26.2         # a recorded session read back from the JSON alone, in another language
go run ./gen/cmd/schemacov 26.2                         # how much of the packet schema is typed
go run ./gen/cmd/packetdiff 26.1 26.2                   # wire-layout changes between two versions
go run ./gen/cmd/source 26.3 LocalPlayer                # a vanilla class as readable Java under temp/source/ (never committed)
go run ./gen/cmd/mcmeta diff 26.2 26.3-pre-2            # registry preview without Java (misode/mcmeta)

A release is the same chain plus commits and tags in the sibling checkouts (../mc26-data, ../mc26-data-pre, ../go-mc26); nothing is pushed without --push:

go run ./gen/cmd/mc26 release --version 26.2            # branches mc-26.2, tags v0.262.<n> / v0.262.<patch>
go run ./gen/cmd/mc26 release --version 26.2 --push

• pipeline (.github/workflows/pipeline.yml): every pull request, and on demand for any version — the local pipeline --smoke --e2e, plus the coverage report and the artifacts.
• release (.github/workflows/release.yml): on demand with a version — the local release --e2e --push, with a write deploy key per target repository (docs/release.md). Tags are created only here.

The smoke test joins the server, waits for chunks and its own chat echo. The end-to-end run builds every example against the built library and checks: mcping reports the version; daze sees a broadcast, a private message and an item given over RCON while chunks stream in; two daze bots hear each other's chat (typed on their consoles), and one of them, made an operator, teleports itself to the other (checked with data get entity … Pos) and gives it a diamond the other bot sees in its inventory; minimal and autofish log in; pressureTest logs three bots in; mcadump reads a region file the server wrote.

Versions: Minecraft 26.1 and later, release ids and pre-release ids alike (26.3-pre-2 goes to mc26-data-pre and tags as v0.263.0-pre2.<n>). The three newest Minecraft versions receive fixes; older branches are frozen.

docs/: architecture, generated versus hand-written, what is still hand-written and why, a new Minecraft version, testing, releasing; gen/README.md for the commands, generators and packet structs; data-gen/README.md for the extractors. wip/ is the backlog: one task per file, in order, with the decisions that are still open and the records of what was done.

Built with Claude Opus and Claude Fable. Carries code from Tnze/go-mc (MIT); gen/src/COPIED (and COPIED in the kit) lists the origin of every hand-written file — go run ./gen/cmd/mc26 report --version 26.2 measures the split.