Basic Weighted Random Events

— by Arcanox

This is a coded script made to choose 1 of a selection of random events based on RNG weight depending on the selected occurrence chance.

It allows the bot creator to choose the overall likelihood of a selection of random events occurring, then lets them fine tune the likelihood of each individual random event occurring by adjusting the RNG weight.

Included debug messages.

1. "arc.testRandom" Is for testing the weights (likelihoods) of the RNG events you have created. [Only necessary if you wish to use different event weights]
2. "[EVENT_NAME] + arc.force_event" Is for testing if the tokens you used for the event function as intended.

Note: The LLM is known for ignoring events so you may have the LLM ignoring the events anyway. This is what the debug console readouts are for so you can confirm the tokens were actually added and it's not just the LLM ignoring them.

By default, this script includes 5 weather events with different weights assigned to them.

You can change them however you wish.

Note: An updated version of this template will be released when persistence is added.

It will include the following:

1. Event Persistence (something to make the events last longer)
2. Event Cooldown (to prevent multiple events from occurring in a row due to RNG)

If you encounter issues with the template, please mention @arcanox_null (UID: 1233115215693086821) and make a script forum post on the Janitor Community Discord.

/*
 * Arcanox's Explanation
 * This is a coded script that chooses *1* of a selection of defined events when triggered
 * Ideal for situations where you only want *1* event of a specific type to occur
 * Optional weight to increase or decrease the likelihood of a specific event to occurr
 * Includes debug triggers to test RNG event likelihood
 * "arc.testRandom" - Used for checking the likelihood of events based off the chosen RNG weight
 * "[EVENT_NAME] + arc.force_event" - For checking if the LLM actually responds to a specific event properly
 *
 * [!IMPORTANT!]: Please be advised, the LLM may still choose to ignore these events.
 */

/* 
 * Events Script
 * Choses an event randomly based on the eventChance or from a debug trigger word 
 * 5 Total Entries
 * Note: RNG has higher priority than trigger words, only 1 event can trigger at a time
 */ 

const lastMessage = context.chat.last_message.toLowerCase();
const eventPrompts = ["wildfire", "tornado", "sandstorm", "blizzard", "tsunami"]; // Event names for RNG selection
const eventWeights = [0.5, 2, 1, 1.5, 0.2]; // Assign a weight to each by index; higher being more likely

// Define the tokens added to the scenario for each specific event
const eventDescriptions = {
  wildfire:  ", a wildfire begins across the horizon",    // Weight = 0.5
  tornado:   ", a tornado begins across the horizon",     // Weight = 2
  sandstorm: ", a sandstorm begins across the horizon",   // Weight = 1
  blizzard:  ", a blizzard begins across the horizon",    // Weight = 1.5
  tsunami:   ", a tsunami can be seen in the distance"    // Weight = 0.2
}; 

let eventChance = 0.1; // % chance for an event to occur each user message | 0.01 = 1% | 0.1 = 10% | 0.25 = 25% | 0.5 = 50% | 0.99 = 99%

if ((lastMessage.includes('arc.testrandom'))) { // Forces a RANDOM event to occur
  eventChance = 0.9999999; // Sets RNG chance to 99.99% chance to force a random event | DO NOT SET TO 1, the script will break
}

// Helper: picks one item from items[] according to weights[]
function weightedRandomChoice(items, weights) {
  const totalWeight = weights.reduce((sum, w) => sum + w, 0);
  let r = Math.random() * totalWeight;

  for (let i = 0; i < items.length; i++) {
    if (r < weights[i]) {
      return items[i];
    }
    r -= weights[i];
  }
}

let chosenEvent = "n/a"; // 
if (Math.random() < eventChance) {
  chosenEvent = weightedRandomChoice(eventPrompts, eventWeights);
}
const triggeredEvent = eventPrompts.find(e => 
  lastMessage.includes(e) && lastMessage.includes('arc.force_event')
); // Looks for the first event mentioned, then activates that event if the secondary debug trigger words are entered

const eventToFire = triggeredEvent || chosenEvent; // Prioritizes events from trigger words over RNG events
if (eventToFire) {
  context.character.scenario += `\n${eventDescriptions[eventToFire]}\n`;
  console.log(`-:{Probability Script}:-`);
  console.log(`Random Event Chosen: ${chosenEvent}`);
  console.log(`Event Added: ${eventToFire}`); 
  console.log(`Code Added: ${eventDescriptions[eventToFire]}`)
  console.log(`-|:|:|:|:|:|:|:|:|:|:|:|-`)
}

Updated on: 12/09/2025