-`mc-*` commands operate on the shared local Minecraft server.
-`mcc-*` commands operate on one MCC client session.
- The default `session` is the current worktree name.
- The default username is derived from `session`, so two worktrees can join the same shared server without kicking each other.
-`MCC_SERVERS` remains the shared server-root override.
Keep shared servers running by default. Do not stop or reset them unless the user explicitly asks for that, or you need to switch server versions.
### tmpfs build mode
```bash
source tools/mcc-env.sh
export MCC_BUILD_MODE=tmpfs
mcc-build
mcc-build-clean
```
When `MCC_BUILD_MODE=tmpfs`, build output goes to `/dev/shm/mcc-build/<worktree>/` on Linux, or `${TMPDIR:-/tmp}/mcc-build/<worktree>/` when `/dev/shm` is unavailable.
| Server data reports | `java -DbundlerMainClass=net.minecraft.data.Main -jar server.jar --reports` | **Yes** |
**Important since MC 1.21.9**: Some items and blocks are registered outside `Items.java`/`Blocks.java` field declarations (via block registration callbacks). In these cases, the decompiled source undercounts entries. **Always use server data reports** for item and block palettes when available.
## diff_registries.py — Compare registries between versions
Compares Items, EntityTypes, Blocks, DataComponents, and EntityDataSerializers between two MC versions. Reports whether each palette needs updating, lists added/removed entries, and shows ID shift statistics.
The `--registry` flag enables cross-validation: compares the count and set of entries found in decompiled Java source against the server's authoritative registry. Any mismatches indicate that palette generation must use server data instead of Java source.
Validates each item name against `ItemType.cs` and warns about missing enum values. Add missing values to `ItemType.cs` in alphabetical order before compiling.
Generates a complete block palette with block state ID ranges from the server's `blocks.json`. Validates against `Material.cs` and warns about missing enum values.
Reads `EntityDataSerializers.java` static block registration order. Maps Java field names to MCC's `EntityMetaDataType` enum. If a new serializer type appears that isn't in the mapping table, it will warn you to update:
Reads `ArgumentTypeInfos.java`, skips the `SharedConstants.IS_RUNNING_IN_IDE` block, and prints C# array initializers for the runtime `COMMAND_ARGUMENT_TYPE` registry order. Use this when Mojang inserts new command argument types and the modern `DeclareCommands` parser needs updated ID routing.
-`MapColor.java` -- extracts the 64 base MapColor constants and their RGB values
-`DyeColor.java` -- maps dye colors to MapColor constants
-`Blocks.java` -- determines each block's assigned MapColor via `.mapColor()` calls
Output: `MinecraftClient/Tui/MinimapBlockColors.json` (embedded as a resource via `.csproj`). Contains color entries, plus lists of transparent, water, and ice materials.
Validates each block name against MCC's `Material.cs` enum. Blocks without a matching enum value are skipped.
Parses `EntityType.java` to read each entity's `MobCategory` assignment from the `EntityType.Builder.of(Factory, MobCategory.XXX)` call. Maps Minecraft categories to MCC minimap categories:
- **Neutral mobs** (e.g. Enderman, Spider, Wolf, Bee) -- Minecraft has no "neutral" category; these are MONSTER or CREATURE in code but only attack when provoked
- **Passive overrides** (e.g. Villager, WanderingTrader) -- classified as MISC in Minecraft for spawning reasons but should appear as passive on the minimap
Output: `MinecraftClient/Tui/MinimapEntityCategories.json` (embedded as a resource via `.csproj`). Validates each entity name against MCC's `EntityType.cs` enum.
