Minecraft anticheat guide
Raw Mouse Residual Checks for Aimbot Staff
How FairPlay's raw mouse residual checks measure off-grid and unstable input, why ordinary rounding is excluded, and what staff should verify before acting.
What are the raw mouse residual checks measuring?
These checks measure the gap between an observed rotation and the nearest value a mouse step could explain. The gap is called a residual here. A residual is small when the rotation sits close to a plausible step and larger when it sits far from one. Seven checks in this family read residuals, input model stability, or small-step behavior.
The seven checks are Kitten, Liquid, Water, Input Model Instability, Mouse Delta Enclosed Invalid, Mouse Delta Off Grid and Randomizer Flaw. They overlap in what they read, but each one asks a different question about the residual. Some look at the value of one delta. Others look at how the model estimating the mouse behaves across consecutive moves.
An alert here means the input did not fit the model at that moment. It does not tell you what produced the input.
Which cheat behavior does this family target?
The family targets rotation that a server cannot reconcile with any mouse step. Software that writes view angles directly often produces values that are either exact in an unnatural way or that drift away from every plausible step. The residual checks are written to notice that drift, and the input model checks are written to notice when the estimate of the player's mouse keeps changing in a way a steady device would not produce.
Randomizer Flaw is a different case. It looks for pitch that should be scattered after a randomization step but still lines up with a fixed grid when the pitch moved enough to matter. A player whose pitch carries a strong grid after a movement that should have been random is the pattern this check describes.
Water looks at movement that stays near zero on one axis, and Kitten looks at small deltas measured against a repeating base. These patterns are common in aim tools that hold a fixed step, but they are also common in careful human play, so they are a weak signal alone.
Why does ordinary rounding not count as a residual?
The most important design point in this family is what it leaves out. Rounding a rotation to the nearest inferred mouse step always leaves a small leftover, and that leftover stays within the normal rounding range. The Mouse Delta Enclosed Invalid check is written so that this normal leftover is not treated as evidence. The rule is simple to state and easy to forget when reading an alert.
When you read an alert from this family, check whether the residual was large compared with a step, or whether it was just the normal rounding remainder. An alert built only on rounding is a sign of a bug or a misread, not of cheating, and it should be reported to the people who maintain the checks rather than used against a player.
Which legitimate input looks like a residual?
A player on a different mouse can produce a residual pattern that looks unusual for the model the server expects. So can a player who switches between a mouse and a trackpad during a session.
Pointer settings matter a lot here. Operating-system pointer acceleration makes the same physical motion produce different movement depending on speed, which spreads residuals across the range. Frame-rate changes can also shift how the game samples the mouse, and a player whose frame rate drops during a fight may show a different pattern for a few seconds.
Network conditions can add noise to the stream the server sees. Packets that arrive late or in clumps change the timing of rotations, and the input model reads timing as part of its estimate. A short unstable stretch during heavy lag is not the same as a steady cheat.
How should staff verify a residual alert?
Begin with the shape of the alert, not its size. A single large residual inside a long steady record reads very differently from a run of medium residuals that never settles. The table below lists the usual shapes and the check you should make before concluding anything.
Ask the player for their mouse, pointer and frame-rate setup, and compare that with the alert time. If the setup changed during the session, the input model may simply have learned the old device. Re-run the same fight on a second occasion before you treat the alert as settled.
| Shape of the alert | What it often means | Check before acting |
|---|---|---|
| One large residual inside a steady record | A single odd packet or a brief lag spike | Replay the window and look for lag evidence around it |
| Medium residuals that never settle | A changing setup or a device switch | Ask about mouse, trackpad and pointer changes during the session |
| Residuals that cluster on one axis | Pointer or sampling behavior on that axis | Compare the other axis in the same window and a second session |
| Alert that only appears after a rounding-sized gap | A misread of normal rounding | Report it to maintainers and do not use it on the player |
What staff should change only in staging
Residual checks depend on how the server estimates the input model, so changes here should always be tested against replays.
Use per-check permissions to exempt a known setup, such as a player who uses a drawing tablet, instead of loosening the family for every player. Keep the exemption tied to a named account and a reason, so a later reviewer can see why it exists.
Where does this family stop?
These checks read the server's view of input. If a modified client changes how it reports rotation, the residuals describe that report and not the physical mouse.
Use the residual alerts as a prompt for a question. Ask whether the input changed, whether the setup changed, and whether the timing was disturbed. Only after those questions are answered does an alert from this family carry any weight.
FAQ
What is a residual in plain words?
It is the distance between the rotation a player produced and the nearest value that a mouse step could explain. A small distance is normal. A large or persistent distance is what the family reads.
Why does the family ignore normal rounding?
Rounding to the nearest step always leaves a small remainder. Treating that remainder as evidence would make ordinary input look suspicious, so the design excludes it.
Can a trackpad or tablet player trigger these checks?
Yes, a change of device or a tablet can produce input that does not match the model the server expects. Ask about the setup before reading any residual alert from that player.