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Show HN: NeoMud – A multiplayer dungeon game with AI agents that QA and playtest

https://github.com/terrymaster/NeoMud

  I've been building a modern take on a MUD (multiplayer text RPG) with Claude Code over the past few weeks. Kotlin server, Android client, React-based world editor. The usual hobby project stuff.

  The interesting part is the agent pipeline that grew around it:

  - A /game-designer agent reads all the world data files, models the combat math, and produces balance proposals with specific JSON changes
  - A /playtest agent connects to the running game server over WebSocket, creates a character, explores, fights NPCs, loots items, and files GitHub issues for bugs it encounters
  - A /worldmaker agent drives the world editor in a real browser via Playwright — clicks through zone editing, NPC configuration, item creation, and files issues when things break
  - A /bugfixer agent picks up those issues and submits fixes

  Each agent has persistent memory across sessions, so the game designer remembers its previous balance audits and the playtester remembers what areas it's already explored.

  The game itself is a modern take on '90s MUDs like MajorMUD — tick-based combat, NPC behaviors (wander, patrol, pursuit), spells, skills, stealth, loot tables, vendors, trainers. 4 zones, 25 rooms, 17 NPCs. Everything is data-driven JSON — the world editor exports .nmd bundles (ZIP archives) that the server loads at startup, similar to DOOM's WAD files.

  The world editor has a visual zone map where you place rooms on a shared coordinate grid, click to connect exits, and configure NPC patrol routes by clicking rooms on the map. All zones share one global coordinate space so rooms can't overlap across zones.

  ~45k lines of code, 830 tests across server/shared/maker, 460 AI-generated assets (images and audio). The agents have filed about 40 GitHub issues so far, most of which are legitimate.

  It's a hobby project — combat balance is rough, there's no quest system yet, and it needs real multiplayer stress testing. But the feedback loop of building features and then having agents test them in the actual running application has been a surprisingly effective workflow.
( 4 comments | on HN )
Re:Show HN: NeoMud – A multiplayer dungeon game with AI agen... by jlongo78 on Saturday March 07, 2026 @11:00AM (#47288770)
persistent sessions are a game-saver. I've lost count of how many times I wished for that during playtesting. How do you handle the AI interactions?
Re:Show HN: NeoMud – A multiplayer dungeon game with AI agen... by terrymaster on Saturday March 07, 2026 @12:20PM (#47289514)
Claude used for most code - MCP setup for skills out to elevenlabs for sfx and bgm generation, using nanobanana2 via openrouter for item/npc sprites and some custom processing to strip backgrounds (since I'm not paying for Adobe)
Re:Show HN: NeoMud – A multiplayer dungeon game with AI agen... by jlongo78 on Saturday March 07, 2026 @12:26PM (#47289561)
nice stack! sounds like a solid pipeline. can’t wait to see those sprites in action.
Re:Show HN: NeoMud – A multiplayer dungeon game with AI agen... by terrymaster on Sunday March 08, 2026 @04:40PM (#47301196)

  Quick update — NeoMud now has a Desktop (JVM) client alongside Android. Same Compose Multiplatform codebase, 89% shared code in commonMain, with expect/actual for the platform-specific bits (JavaFX for audio, Ktor CIO for networking, Logback for logging).

  The Kotlin Multiplatform story for UI is surprisingly mature — JetBrains' Compose Multiplatform let us go from Android-only to Android + Desktop with minimal platform glue. The entire navigation graph, all screens, all viewmodels, and the WebSocket client are shared. Platform targets are basically just
   entry points and audio backends.

  iOS (Kotlin/Native) and Web (Wasm) are next on the roadmap.