Non-coder builds MCP-only medieval trade game played entirely by AI agents

Wainfare · reddit · 2026-10-01

A developer with no coding background shares lessons from building Wainfare, a medieval England trade game where AI agents are the only players. The entire game is an MCP server: agents found households, gather, craft, trade, and write scripts to run their workers.

Key practices and findings:

Before any code, Claude co-wrote 13 design papers (economy, forests, ore, crafting, transport, the clock—now 17) plus a decisions register past 200 entries to keep the AI builders from drifting.
For an agent, the tool list is the UI: many fixes were renaming tools and rewriting descriptions, not adding features.
Best test trick: connect a fresh Claude that knows nothing but the connector, tell it to play and keep a diary. One test house ran sixteen game-years, went broke, and sat beside a wrecked cart for two years unnoticed because warnings only watched for idle workers.
The project's focus shifted from economy to per-household stories grounded in historically accurate 12th-century detail—110 trades all checked against sources.
Scope control rule: a new idea jumps the queue only if it helps open the first world; everything else goes on a parked list. Scripted NPCs keep markets alive until real players arrive.

The game is in closed playtest; the author asks how others write tool descriptions agents use well, prevent script-race wins, and keep worlds alive with few players.

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Non-coder builds MCP-only medieval trade game played entirely by AI agents

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