Short answer: No. It is not.
First of all, the main point needs to be mentioned: GOSU Voice Assistant works together with the official API from RIOT Games. RIOT Games has provided us with access to their API only after reading the Voice Assistant's technical documentation and description. Thus, currently, GOSU Voice Assistant is officially approved for development by RIOT Games.
If that doesn't satisfy you, let's explain a bit further:
If you have a friend sitting next to you, telling you what to buy or what spell to level up, that doesn't mean you are cheating.
When GOSU Voice Assistant warns players that a gank might be coming, it doesn't see the map or where the enemies are on it. It reminds you that at certain times in the game, Junglers usually hit level three and look for gank opportunities. This is exactly what your friend would do, if he was looking out for your best interest in the game.
What is the definition of a cheat, has to do with what information is available to the cheater. If the application analyzes the in-game situation and acquires data that is not already provided by Riot API, that, of course, would be considered as, and to be frank, is cheating. GOSU Voice Assistant does not read the in-game situation, it only uses data provided by Riot API.
For example, if GOSU Voice Assistant was analyzing the situation of the game and watching the minimap and was seeing the Jungler move from the mid lane to the bot lane, then noticed that it had disappeared into the fog of war and it warned players that a gank might be coming, this would be considered illegal, because it would have acquired the data by watching the minimap. Since Riot API does not provide information about where players are moving or where they are on the map during the game it is not illegal.
From a technical perspective, here is a short guide on how GOSU Voice Assistant works:
- It obtains state of the game from LoL Client API for the current match:
- Also we obtain historical data from LoL web APIs:
https://developer.riotgames.com/apis for the selected summoner.
- It analyzes game situations to recommend game events beneficial for the player:
Through analyzing game events, the current game situation, and historical data, GOSU Voice Assistant produces meaningful advice for moments of in-game to give the player the edge.