/debug

Starts or stops a debug profiling session, or profiles a specific function. Generates a profiling report in the debug folder.

Overview

Starts or stops a debug profiling session, or profiles a specific function. Generates a profiling report in the debug folder. In vanilla Minecraft Java Edition it is one of the special commands and has been available since version 1.0.

It is invoked as /debug [] and accepts one required argument () and one optional argument ([function]).

Profiling reports are saved in the 'debug' folder within the world directory. The report includes tick timing, entity counts, and other performance data. Useful for identifying lag sources.

A start/stop session writes a profiling report into the world's debug folder once stopped; there is no live readout. The report captures tick timing and entity counts for tracking down lag.

Syntax & Arguments

/debug <start|stop|function> [<function>]

The full syntax is /debug []. Angle brackets < > mark required arguments and square brackets [ ] mark optional ones; a vertical bar | between words means you pick exactly one of those literals. You must always supply . The argument [function] may be omitted, in which case the documented default applies.

action: Required, of type a literal. start = begin profiling; stop = end profiling and save report; function = profile a specific function.
function: Optional, of type a resource. The function to profile (only for 'function' action).

Parameters

Name	Type	Required	Description
action	literal	Required	start = begin profiling; stop = end profiling and save report; function = profile a specific function.
function	resource	Optional	The function to profile (only for 'function' action).

Examples

The 3 examples below are ready to copy and adapt. For instance, /debug start starts a server profiling session. Each example varies the arguments to show a different real use of /debug; read the note under every snippet to see exactly what changes.

/debug start

Starts a server profiling session.

/debug stop

Stops profiling and saves the report to the debug folder.

/debug function my_pack:heavy_function

Profiles a specific function and outputs performance data.

Permission Level & Requirements

/debug sits at permission Level 3 - Admin, which means it needs permission level 3 (administrator).

Requires level 3.

This reference describes the Java Edition 1.21 form of the command; Bedrock Edition may use slightly different argument formats.

Common Mistakes

Running /debug start without /debug stop, the profiling session continues until stopped, collecting data indefinitely.
Expecting real-time output, the report is saved as a file after stopping.

Notes

Profiling reports are saved in the 'debug' folder within the world directory. The report includes tick timing, entity counts, and other performance data. Useful for identifying lag sources.

Related Commands

If /debug is part of your toolkit, the commands below are the ones you will most often reach for alongside it: /function and /tick. They cover closely related tasks, so the links above jump straight to each one.

/function

/tick

Frequently Asked Questions about /debug

What does the /debug command do in Minecraft?

Starts or stops a debug profiling session, or profiles a specific function. Generates a profiling report in the debug folder. It belongs to the special command group and was added in Java Edition 1.0.

What is the correct syntax for /debug?

/debug []. The required argument is action, and the optional one is function.

What permission level does /debug need?

It requires permission Level 3 - Admin. On a server the player must be an operator at that level, or have cheats enabled in single-player.

What is a common mistake when using /debug?

Running /debug start without /debug stop, the profiling session continues until stopped, collecting data indefinitely.

Can you give an example of /debug in use?

Yes. /debug stop — stops profiling and saves the report to the debug folder.

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