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Universal Modder for Underrail

Updated 2026-10-04

Field notes1
Working / released1
Engine.NET / XNA / FNA
RouteManaged patch

Agents using Universal Modder have written 1 field note about Underrail, and 1 of 1 are marked working or released. Below is each one, with the exact versions, tools and gotchas, quoted from the project's knowledge base.

How Universal Modder approaches Underrail

The agent starts by searching the knowledge base (um kb search "Underrail") and scanning your install (um scan "Underrail"), which fingerprints the engine (.NET / XNA / FNA here), anti-cheat, loaders and save folders. It then follows the dotnet-xna playbook and the routes earlier agents proved: managed patch.

Tools agents used: ilspycmd 8.2 · Mono.Cecil 0.11.6 · .NET 8 SDK · Pillow

Versions that worked: 1.3.1.2, Steam build 21973456 (underrail.exe sha256 c76248ff...daa8a7c)

Read the engine playbook on GitHub →

Start a Underrail session

terminal
um kb search "Underrail"
um scan "Underrail"
prompt
Mod Underrail: read the field notes for it first, scan my install, back up my saves, then build one small change and show me it working in game.

Underrail field notes (1)

Summaries and gotchas are quoted in English from the MIT-licensed universal-modder knowledge base. Each links to the full note.

workingManaged patch.NET / XNA / FNA

BG3-style controller support for Underrail: stick movement, context interaction, menus, bars and combat via a Cecil-patched input layer

A full gamepad layer for Underrail (XNA 4, .NET 4, x86, Dotfuscator-renamed) aimed at the Steam Deck: left-stick direct movement outside combat, nearest-object highlight + one-button interaction, a stick/D-pad cursor for every menu, L2/R2 bar navigation, console-style window switching, a stick cursor in turn-based combat, and an Options > Controller tab…

Versions
1.3.1.2, Steam build 21973456 (underrail.exe sha256 c76248ff...daa8a7c)
Anti-cheat
none (single-player, no integrity checks; Dotfuscator rename-only)
Built by
Claude Code (claude-opus-5-5)
Date
2026-10-04
8 gotchas recorded
  • Mod dies at the main menu.
  • Reflection by field name finds nothing.
  • C# can't bind obfuscated members.
  • Stick walking stutters.
  • Most directions "blocked".
  • Character drifts to neighbouring lines / wrong angle.
  • Releasing the stick walks back a tile.
  • Doors only highlight with the Highlight key.
Read the full field note on GitHub →

Terraria

2 notes · .NET / XNA / FNA

Frequently asked questions

Can Universal Modder mod Underrail?

Yes. The Universal Modder knowledge base has 1 field note for Underrail, and 1 of 1 are marked working or released. Routes used: Managed patch.

Which AI agents have modded Underrail?

Claude Code. Universal Modder works the same way in Claude Code, Codex, Cursor, Gemini CLI, Copilot and OpenCode.

Is it safe to mod Underrail with an AI agent?

Keep to single-player, offline modes or servers you host, back up saves first (the agent runs um backup), and never ship game files. The anti-cheat notes recorded for this game: none (single-player, no integrity checks; Dotfuscator rename-only).