How to build MMORPG tools and tests with Claude Code
khyrichan used Claude Code to build a Unity MMORPG and custom data tools. A small closed alpha reportedly ran without server crashes; an additional save-compatibility check later found two issues requiring fixes.
reddit.com
Suggested prompt
Suggested prompt written by Agents In Use, not the source author. Replace bracketed inputs and review tool permissions first.
Help develop [game] using [engine and networking stack]. Work from my approved design and actual game-data formats. Build small editors for [entities, items and environments], with tests and documented invariants. Test older saves against changed data and report failures separately from fixes. Keep deployment and release decisions with me. Do not treat a small alpha or passing checks as proof of production reliability.
Reach people exploring AI agents
See placements →Evidence at a glance
Sourced account- Source poster / publisher
- u/khyrichan
- Original account
- Read the source ↗
- Published
- Source link checked
- Reported result
- The author reports three Windows data tools, supporting deployment infrastructure and a closed alpha with eight concurrent players and no server crashes. A later check of 25 saves covering 231 items found two unresolved issues. These are author claims, not independently reproduced results.
- Human involvement
- The developer chooses the design, mechanics, world and lore, tests the game and invests substantial personal development time. A reader identified a missing save-compatibility test, and the author reports two remaining issues rather than claiming a completed fix.
A linked account supports attribution. It does not mean we independently reproduced its result.
Report an issue with this case
Open correction emailOpens your email app with the case link included. Nothing is sent automatically.
How the agent did it
- The developer established the game's visual style and used Claude with Blender through MCP for assets and cities.
- With Claude Code, the developer built tools for creature data, items and world construction, plus supporting infrastructure.
- The author ran a closed alpha and maintained automated tests and invariant checks with Claude's help.
French solo developer khyrichan reports building Death Leaves a Trace, an isometric MMORPG, with Claude Code alongside a day job. The project uses Unity 6 and Mirror. Claude also works with Blender through MCP to create assets and city environments after the developer established a visual style with purchased asset packs.
The development work extends beyond the game client. The author built three Windows tools with Claude Code: Workshop for creatures, characters and loot, Forge for items and attributes, and Cartographer for environments and world objects. These tools operate on the game's actual data. A custom launcher, deployment pipeline and server dashboard support the project.
Claude helps maintain automated tests, 23 invariant checks and documentation for the client and dedicated Linux server. In the comments, a reader asks about older character saves. The author says those checks did not cover that case, then reports testing 25 real saves containing 231 items. That check found two issues still awaiting fixes and was to become part of deployment checks.
The first closed alpha reportedly reached eight simultaneous players without server crashes. That is a small author-reported test, not evidence of large-scale reliability. The developer retains game direction, design decisions and testing, with almost 400 hours invested since August. This account suits solo game developers considering custom data tools and regression checks alongside AI-assisted implementation.
Prompt
Suggested prompt (written by Agents In Use, not the author's)
Source: Reddit · u/khyrichan
Frequently asked questions
Do the 23 invariant checks establish save compatibility?
No. The author says those checks covered other systems. A separate test of 25 saves covering 231 items found two issues that still needed fixes.
How much of the game did the author leave to Claude?
The author describes Claude as a technical assistant while retaining direction, design decisions and testing. They report almost 400 hours of personal work since August.
More details
Remaining steps
- After reader feedback, the author tested older saves, found two issues and planned to add that check to deployments.
About this account
Claude Code assists implementation across game systems, custom editors, infrastructure and tests. Claude also uses Blender through MCP. The source does not show a complete autonomous development run or establish that the later save test was executed independently by the agent.
Firsthand account by u/khyrichan: https://www.reddit.com/r/ClaudeAI/comments/1x8j8k5/im_building_a_full_mmorpg_solo_with_claude_code/. Full public RSS post and returned comments captured on 19 October 2026. Body eligibility passed at 0.92. Outcomes are author-reported, not independently reproduced. Suggested prompt by Agents In Use, not the author's original prompt.
Credit: u/khyrichan on Reddit
Source published
Added to Agents In Use
Source checked
Tools and topics
Claude Code · Unity 6 · Mirror · Blender · MCP
game development · regression testing · custom tooling · MMORPG
Editorial completeness: 100/100. Measures documented fields, not agent performance or verified outcomes.