General Overview
Most of the Five Nights at Freddy's games follow a very similiar formula gameplay-wise. In general, most FNAF games involve you preventing a set of animatronics from entering the refuge you're staying in, most commonly a security office of some kind. The games have not been afraid to mess with this formula over the 9+ years the franchise has been running, but that general description of events is present in some form in every game. The core concept of the FNAF animatronic's AI is the following: at the beginning of each night, each animatronic is assigned a value from 0-20. This value is predetermined, either by the creator for each main night or set by the player in the Custom Night game mode. Over the course of the night, certain animatronics' values will increase, making them more difficult so as to prevent the night from feeling stagnant. Not all animatronics have this nightly increase, as some are meant to not become active until later nights.
Five Nights At Freddy's
The original Five Nights at Freddy's laid the groundwork for the rest of the franchise to come,
and this is no different when it comes to the AI department.
There are three animatronics who's AI levels increase over the course of the night:
Bonnie (+1 at 2, 3, and 4 am), Chica (+1 at 3 and 4 am), and Foxy (+1 at 3 and 4 am).
Below is a table of all of the FNAF animatronics' AI levels at the start of the night.
| Night | Freddy | Bonnie | Chica | Foxy |
|---|---|---|---|---|
| 1 | 0 | 0 | 0 | 0 |
| 2 | 0 | 3 | 1 | 1 |
| 3 | 1 | 0 | 5 | 2 |
| 4 | 1/2* | 2 | 4 | 6 |
| 5 | 3 | 5 | 7 | 5 |
| 6 | 4 | 10 | 12 | 16 |
*There is a 50/50 chance either will occur.
Five Nights At Freddy's 2
FNAF 2 works mostly similiarly to FNAF 1 with some major differences. Firstly, the AI levels don't consistently increase over time like in FNAF 1, instead the increase is scripted per night. Additionally, there are 3 special characters who don't use the same AI system. First I will go over the night AI levels and increases, then I will discuss the alternate AI systems.
| Night | Time | Toy Freddy | Toy Bonnie | Toy Chica | Mangle | Withered Freddy | Withered Bonnie | Withered Chica | The Puppet | BB |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 12 AM | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
| 1 | 1 AM | 0 | 2 | 2 | 0 | 0 | 0 | 0 | 1 | 0 |
| 1 | 2 AM | 2 | 3 | 2 | 0 | 0 | 0 | 0 | 1 | 0 |
| 2 | 12 AM | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 5 | 0 |
| 2 | 1 AM | 2 | 3 | 3 | 3 | 0 | 0 | 0 | 5 | 3 |
| 3 | 12 AM | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 8 | 1 |
| 3 | 1 AM | 0 | 1 | 1 | 0 | 2 | 2 | 2 | 8 | 1 |
| 4 | 12 AM | 0 | 0 | 0 | 5 | 0 | 1 | 0 | 9 | 3 |
| 4 | 2 AM | 0 | 1 | 0 | 3 | 5 | 4 | 4 | 7 | 3 |
| 5 | 12 AM | 5 | 2 | 2 | 1 | 2 | 2 | 2 | 10 | 5 |
| 5 | 1 AM | 1 | 2 | 2 | 10 | 5 | 5 | 5 | 10 | 5 |
| 6 | 12 AM | 0 | 0 | 0 | 3 | 5 | 5 | 5 | 15 | 5 |
| 6 | 2 AM | 5 | 5 | 5 | 10 | 10 | 10 | 10 | 15 | 9 |
When it comes to the more specialized AIs, there are three offenders: Withered Foxy, The Puppet, and Golden Freddy. Golden Freddy has a 1/1000 chance to appear on nights 2-3, a 1/100 chance to appear on nights 4-5, a 1/10 chance to appear on night 6 before 2 am, and after that his AI is simply set to 3. Withered Foxy has an AI level, however I did not include it on the list due to other effects he also has. He checks for movement oppertunities similiar to other animatronics, but he has several quirks that make it so his AI isn't the primary force behind his movement. He has a variable in his code that will increase the longer animatronics are in your office, effectively increasing his AI the more he fails his movement oppertunities. You can flash your flashlight at Foxy, which will increase a flashlight counter. When it reaches it's max, it will reset all of Foxy's timers, sending him back to his starting position. The Puppet's AI is listed in the above table, but it's AI isn't what effects her appearance the most. That would be the music box timer, which also changes nightly like the AI level. While the AI levels only control how long it will take her to reach your office upon being freed, the music box timer is what prevents her from being freed in the first place. Every 50 milliseconds, a value is subtracted from the music box timer. Below is a table of the times.
| Night | Subtraction Value |
|---|---|
| 1 | 2 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
| 6 | 6 |