CurseForge said Client, but Fabric wanted the mod on the server

A new Prominence II server never made it past Fabric’s dependency check:

Mod 'Simply Swords' (simplyswords) 1.70.2-1.20.1 requires any version of simplytooltips, which is missing!
Mod 'Simply Bows' (simplybows) 0.1.4 requires any version of simplytooltips, which is missing!

That sounds like a plain missing-mod problem. The confusing part was that Simply Tooltips belonged to the modpack already. The server used AUTO_CURSEFORGE from itzg/minecraft-server, which removes files marked as client-only when it prepares a dedicated server. CurseForge had marked the exact Fabric 1.20.1 file as Client, so the filter left it out.

Usually that is the right call. A dedicated server has no use for rendering, keybinding, or screen mods. I did not want to defeat the filter just because two other mods complained.

I downloaded SimplyTooltips-fabric-0.1.5-1.20.1.jar and checked the file itself. It was 5,518,319 bytes, and its SHA-1 matched the value from CurseForge: 754b2989e11389f99a032b9031e28b90d8f63205.

Its fabric.mod.json disagreed with the marketplace label:

{
  "id": "simplytooltips",
  "version": "0.1.5-1.20.1",
  "environment": "*",
  "entrypoints": {
    "main": [
      "net.sweenus.simplytooltips.fabric.SimplyTooltipsFabric"
    ],
    "client": [
      "net.sweenus.simplytooltips.fabric.client.SimplyTooltipsFabricClient"
    ]
  }
}

"environment": "*" allows the mod in both client and server environments. The JAR also has a common main entrypoint in addition to its client entrypoint. CurseForge called the file client-only; the file itself and the installed dependency graph said the server needed it.

The persistent fix in Yggdrasil PR #37 was one line:

CF_FORCE_INCLUDE_MODS=simply-tooltips

This override does not fetch some unrelated latest version. CF_FORCE_INCLUDE_MODS tells the server-pack filter to retain a project that the modpack already includes.

The existing installation added one more wrinkle. Its startup log said the requested Prominence II v4.1.0 pack was already installed, so changing the include rule alone would not rebuild the server files. I temporarily enabled CF_FORCE_SYNCHRONIZE=true for one reconciliation, then removed it instead of keeping a repair switch in the normal config.

The Client tag was a good reason to stop and inspect the file, but not a good reason to keep deleting it after that inspection. The config now preserves only the simply-tooltips slug. If a future JAR changes its own environment metadata, that exception will need another look.