Pumpkin Agents

A Minecraft (Paper 1.19.4) plugin for the ACS-204 Artificial Intelligence course at Constructor University Bremen. Each carved pumpkin on a flat world is an autonomous agent: it senses the cells around it, decides with one AI method from the syllabus, and acts — hopping one block per scheduler step, or picking up the block above it. The world is both the simulator and the renderer.

Brains

One brain ships per phase of the syllabus. Phase 0 (situated) is ReflexBrain, a right-hand wall follower. Phase 1 (search) covers BfsBrain, DfsBrain, UcsBrain, and AStarBrain (Manhattan, Euclidean, and a deliberately inadmissible heuristic). Phase 2 (adversarial) pits MinimaxBrain and AlphaBetaBrain against each other in Pumpkin Tag. Phase 3 (reasoning) is PrologBrain, which solves a Wumpus world with real Prolog inference on 2p-kt.

Source lives under plugin/src/main/kotlin/agent/brains/.

Run it

The Gradle run task self-provisions everything — it downloads the pinned Paper 1.19.4 build, builds against a local JDK 21 toolchain, installs the plugin, copies the benchmark maps, and boots the server:

./gradlew run

To run the production server in Docker instead — handy for a longer-lived or remote instance — build the plugin jar and hand it to a Paper image:

./gradlew :plugin:shadowJar    # produces plugin/build/libs/pumpkin-agents-0.1.0-all.jar

docker run -d --name pumpkins -p 25565:25565 \
  -e EULA=TRUE -e TYPE=PAPER -e VERSION=1.19.4 \
  -v "$PWD/plugin/build/libs/pumpkin-agents-0.1.0-all.jar:/plugins/pumpkin-agents.jar" \
  -v "$PWD/maps:/data/plugins/PumpkinAgents/maps" \
  itzg/minecraft-server

Then drive it from the in-game console:

/pumpkin map load wumpus_8     # load a benchmark map
/pumpkin spawn PROLOG 1 1      # spawn a brain at (x, z)
/pumpkin run 200               # advance the scheduler 200 steps
/pumpkin state                 # what the agent sees and believes
/pumpkin metrics               # print + append a row to metrics.csv

To watch the agents live, point any Minecraft 1.19.4 client (for example, Prism Launcher) at localhost server.

Other commands: map save, step (one tick), reset (clear agents, keep the map). Brains accepted by spawn: REFLEX BFS DFS UCS ASTAR ASTAR_EUCLID ASTAR_BAD MINIMAX ALPHABETA PROLOG.

Test it

./gradlew :plugin:test    # fast Kotest unit tests for the brains
./gradlew check           # unit + e2e (boots a real Paper server, drives /pumpkin over RCON)

Configure it

plugins/PumpkinAgents/config.json, written on first launch:

{ "decisionsPerSecond": 2, "randomSeed": 1234, "defaultBrain": "ASTAR" }

Built on plugin-api — a Kotlin/Bukkit DSL the author wrote in 2019–2020, used here unmodified. See REPORT.md for the write-up and DEMO.md for the video walkthrough.