DebugBridge
by weikeng
DebugBridge lets a running Minecraft client expose its game state to external tools through a localhost WebSocket server, with a bundled web UI for inspection.
What it does
Once the Fabric client mod starts, it runs a localhost-only WebSocket server on the default port 9876, scanning ports 9876 to 9886 if that one is taken. Command-line scripts, the bundled Vue web UI and MCP clients such as Claude can connect to it and read or change the state of the game as it runs.
Developers and AI-assisted debugging workflows are the audience the mod is built for. The 2.0.0 release left the Groovy 5 scripting model and the endpoint set unchanged, so scripts written for it still work, and the 2.1.0 file is the newest build for 26.2. The mod is open source under the MIT License and runs on the client only, so servers and other players need nothing installed.
Key features
Live Groovy scripting
Inside the Minecraft JVM, Groovy code can reach the full set of game classes, and globals like mc, player and level are already bound when a script starts.
Mapping-aware Java bridge
Mojang names are written in code and resolved to runtime intermediary names automatically, including in obfuscated builds.
Entity and block browsers
The Entities panel lists nearby entities with equipment icons and glow toggling, and the Blocks panel browses nearby block entities such as signs and chests.
Temporary video recording
Video recordings are kept in temporary storage for 24 hours and removed automatically afterward, though a persistent setting writes them into the game directory instead.
Sandboxed scripts with timeouts
Scripts can read and write data files inside a sandbox, and each request has a configurable timeout with a default of 10 seconds and a maximum of 5 minutes.
Compatibility
Latest build for each game version and loader.
26.x4 of 4 versions with builds
1.21.x1 of 1 version with builds
1.19.x5 of 5 versions with builds
This mod also publishes snapshot builds. Snapshots are not shown in the matrix.
Use cases
Who it’s for: The mod is aimed at mod developers and anyone debugging a Minecraft client who wants to script it or inspect it from outside the game.
How it compares
PacketLogger is a Fabric client mod for 1.19.3 – 1.19.4, licensed under the GNU Affero General Public License v3.0 only and open source. Command-MCP is a Fabric server-side mod for 1.20.1 under the GNU General Public License v3.0 only, so it runs on the server rather than the client. DFScript is a client-side Fabric mod for 1.19 – 1.20.4, released under the GNU Lesser General Public License v3.0 only and open source.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| DebugBridge | Fabric | 1.19 – 26.2 | Client-side only | 2026-08-26 |
| PacketLogger | Fabric | 1.19.3 – 1.19.4 | Client-side only | 2023-05-12 |
| Command-MCP | Fabric | 1.20.1 | Server-side only | 2026-08-15 |
| DFScript | Fabric | 1.19 – 1.20.4 | Client-side only | 2024-05-21 |
Questions
Does DebugBridge need to be installed on the server?
Which game versions does DebugBridge support?
Does DebugBridge need Fabric API?
In the catalog
DebugBridge is one of 8,016 Management mods on ModsFinder, and one of 5,930 Management mods for Fabric. 13,894 mods support Minecraft 26.2.
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What the author says
A Fabric client mod for Minecraft (1.19, 1.21.11, exact 26.1, and stable 26.2) that exposes game state over a local WebSocket server, plus a Vue web UI for visual inspection. Built for AI-assisted Minecraft development and debugging. v2.1.0 ships the same stable feature line for every maintained target: Minecraft…
Official listing
- Modrinth page
- modrinth.com/mod/debugbridge
- Owner
- weikeng
- Published
- 2026-04-12
- Updated on Modrinth
- 2026-08-26
- Facts verified
- 2026-10-15