TroubleshootingFix it

Diagnosing input

A systematic way to find out where an input is being lost, from the counters down to the source.

4 min readInputBooster 4.1.2-alphaMinecraft 26.2 / 26.3

When an input does not arrive, the problem is always in one of five places. This page walks them in order, from the cheapest check to the deepest.

The five places an input can be lost

Each stage has its own counter or log line. Start at the top.

Stage 1 — is the press even reaching the game?

Open the settings screen, go to Overview, and read the Keys and Mouse counters.

Symptom	Conclusion
Both counters stay at zero	No event is arriving. Check the log for `All client hooks present.` and whether the client is running the mod at all
The counters rise when you press keys	Events are arriving. Move to stage 2

Stage 2 — which source is live?

The Compatibility tab shows whether the event hooks applied and which mode the engine resolved.

Engine mode	What it means
`event`	The hooks are live and dispatching
`poll`	The poller is the source

If the mode is poll and you expected event, one of these is true:

Cause	Check
The hooks never fired	The log line `Keyboard/mouse event hooks are live.` is missing
An input mod is installed	The Compatibility tab lists it. The fallback downgrades to polling
`engine_mode` is 1 but the hooks are not live	Event mode falls back to polling until the first event proves the hooks work

Stage 3 — is the edge being detected?

The Overview tab's Engine row shows the mode. The overlay's counter line shows the action count:

text

Keys 1.2k  Mouse 430  Actions 880

Actions is the number of actions that were submitted to the dispatcher.

Comparison	Conclusion
Keys and mouse rise, actions do not	The event is not reaching a tracked slot
Actions rise, the queue stays at 0	The actions are being drained immediately
Actions rise, the queue sits at 128	The drainer is not running

Stage 4 — is the queue full?

Reading	Meaning
`Queue 0/128`	Empty. Nothing is waiting
`Queue 127/128` or `128/128`	The drainer is not keeping up, or it is not running
`Queue` growing steadily	The drainer is not running at all

A full queue means new actions are rejected. The physical press is lost. Look for the drainer's failure lines in the log.

Stage 5 — did the drainer execute it?

The drainer runs at the head of the tick. It refuses to execute when:

Condition	How to confirm
A screen is open	The screen hook line in the log
There is no player	Obvious
The mod is not active or not initialised	The `Fatal init error!` line
Safe Mode disabled the `input` module	The `[SafeMode] Module 'input' disabled` line

The per-action conditions

Even when an action reaches the drainer, it may do nothing. Check the condition for that action:

Action	Fails when
`ATTACK_PRESSED`	The hit result is not a living entity within 36 squared units
`USE_PRESSED`	The hit result is not `MISS`
`JUMP_PRESSED`	The player is not grounded, in water, in lava or climbing
`FORWARD_RELEASED`	The forward key is still down
`PICK_BLOCK_PRESSED`	The crosshair is not on a block, or the accessor did not apply

The action reference has the exact rule for each.

The systematic checklist

Read the log

Ready! present? Any Fatal init error!? Any Missing vanilla method(s)? Any [SafeMode] line?

Check the mixin hooks

All client hooks present. and at least one screen hook true?

Read the counters

Do the key and mouse counters move when you press?

Read the engine mode

Is it the mode you expected? If it fell back, why?

Read the queue

Is it empty? Is it full? Both are informative.

Check the action condition

Is the action's precondition actually satisfied in the situation where it fails?

Rule out other mods

Disable the other input mods one at a time. The detector only knows six of them.

A quick self-test

The clearest test of the whole path:

Join a world.
Open the settings screen and note the Keys and Actions counters.
Tap the attack key five times quickly.
Watch the counters.

Result	Where the problem is
Keys did not rise	Stage 1 — the event never arrived
Keys rose, Actions did not	Stage 3 — the edge was not detected
Actions rose, the queue stayed full	Stage 4 — the drainer is not running
Actions rose, the queue emptied, no attack happened	Stage 5 — the action condition failed

Log reference — every line.
Common issues — the fixes.
Engine modes — why the mode is what it is.