Mod Scanner
You have just launched your heavily modded world, and something feels off. A feature is missing, a recipe refuses to appear, or the game simply behaves differently than you expected. The question that follows is almost always the same: did every mod actually load? Mod Scanner exists to answer that question with a clear, no-nonsense report instead of hours of guesswork.
What Is Mod Scanner for Minecraft?
Mod Scanner is a lightweight, client-side diagnostic add-on that checks your mods folder every time you start the game. It counts how many .jar files are present, compares that number to how many actually loaded, and writes the results to a plain text log. If something failed, the exact file name shows up in the report. That is the entire purpose of the tool, and it performs that job extremely well.
There are no new blocks, items, or mobs here. Mod Scanner adds nothing to gameplay. What it adds is certainty, which matters enormously once your mod list grows past a few dozen entries.
How Mod Scanner Works
The add-on runs automatically during startup, so you never need to trigger a scan manually. Once the game reaches the main menu, a report is waiting for you in the modscanner_logs/debug.txt file inside your main Minecraft directory.
What the Report Tells You
- Scans your
/modsfolder and inspects every.jarfile it finds. - Generates a clean, readable summary showing how many mods loaded out of the total detected.
- Lists the exact file name of any mod that failed to load, so you can act immediately.
A typical report looks something like this: the scan completes, reports that 120 of 125 mods loaded from the folder, then names the specific jar files that were skipped. No cryptic stack traces, no digging through launcher logs, just a short list of suspects.
Supported Versions and Loaders
Mod Scanner is built for the Fabric loader and requires Fabric API as a dependency. It is most commonly used on modern releases, including Minecraft 1.20.x and 1.21.x, and it works comfortably alongside large modpacks on those versions. Because it is client-side only, you never need to install it on a server, and it will not cause connection issues on multiplayer worlds.
If you manage several instances across different game versions, keeping the add-on updated matters. The foxygame.net launcher handles that automatically, pushing fresh builds of Mod Scanner to every compatible profile so your diagnostic tool never falls behind the game version you are running.
How to Install Mod Scanner
Setup takes only a couple of minutes, even if you have never added a mod manually before.
- Confirm that Fabric is installed for your chosen Minecraft version.
- Place the Mod Scanner jar file into your
/modsfolder. - Add Fabric API to the same folder, since Mod Scanner depends on it.
- Launch the game and let it reach the main menu.
- Open
modscanner_logs/debug.txtto read your report.
That is the full process. When you download Mod Scanner, keep the jar file name unchanged, because the report references exact file names and an altered name can make troubleshooting harder to follow.
Reading the Results
If the numbers match, you are done and can get back to playing. If they do not, the report hands you a short list of problem files. Common culprits include mods built for the wrong loader, outdated dependencies, or duplicate entries for the same feature. Remove or update the named files, relaunch, and scan again. Repeating this loop quickly narrows a broken pack down to a handful of jars.
Why Modpack Creators Rely on It
Building a pack means juggling hundreds of files, and a single silent failure can break progression in ways that are hard to trace. Mod Scanner turns that invisible problem into a written record you can check in seconds. It is equally useful for players who download a ready-made pack and want to verify that everything arrived intact before starting a long playthrough.
Because the tool is so small, it costs virtually nothing in performance and can safely stay installed permanently. Many players treat it the way they treat a crash log: something you hope never to need, but are always glad to have.
Final Thoughts
Mod Scanner solves one narrow problem with total clarity. It will not fix a broken mod for you, and it will not add content, but it removes the uncertainty that makes modded Minecraft frustrating. Install it once, launch the game, and read the report. From that point forward, you will always know exactly which mods loaded and which ones quietly stayed behind.