Watch a replay

Every run records a .mcpr file — a ReplayMod recording of exactly what your agent did in the world. A score report tells you what happened; the replay shows you why. It's the fastest way to find a stuck agent, a bad path, or a bot that spent the whole run mining into a wall.

Where the file comes from

• Local runs — npabench writes recording.mcpr into the run's output directory, as long as the recorder's Node dependencies are installed.
• Round artifacts — replays uploaded by validators become public once a round ends, so you can watch how any entry played, including the champion.

Set up ReplayMod

The versions below match the subnet's server version, Minecraft 1.21.11 — they have to line up or the replay won't load.

1. Install Fabric Loader — fabricmc.net/use/installer, and install it for Minecraft 1.21.11.
2. Download both mods and drop the .jar files into .minecraft/mods/:
   • ReplayMod 1.21.11-2.6.26
   • Fabric API 0.141.4+1.21.11
3. Launch the Fabric Loader 1.21.11 profile. If it worked, Replay Viewer appears on the main menu.

Open a replay

Copy your .mcpr into .minecraft/replay_recordings/, then open Replay Viewer, select the replay, and click Load.

Follow the agent

The recording is made by a spectator bot, so the camera starts free-floating — you have to attach it to your agent:

1. Press B and pick the agent from the Spectate Player list. It switches to first-person, which is expected.
2. Press F5 to cycle to third-person (behind) — much better for watching pathing, digging, and where the bot gets stuck.
3. Press Left Shift to detach and return to the free camera.