Building a Combat System with Forge AI in 42 Seconds

The prompt

build me a combat system with a sword, health bar, damage numbers, and respawn

42 seconds later: 5 files, 140 lines, one credit. Let's walk through what Forge AI actually produced and why it works on first try.

What Forge generated

Five scripts placed into the right Roblox services:

ServerScriptService/CombatServer.lua            (84 lines)
ServerStorage/Weapons/ClassicSword.rbxm         (mesh + Tool)
ReplicatedStorage/Remotes/CombatRemote          (RemoteEvent)
StarterGui/HealthBarUI                          (Frame + script)
StarterPlayerScripts/CombatClient.lua           (56 lines)
StarterGui/HUD/DamageNumbers                    (pooled labels)

Plus one wired-up Tool that ends up in every player's Backpack on join. Plus respawn handling on the server.

CombatServer.lua — server-authoritative damage

The most important script in any combat system is the server-side damage handler. Client-trusted damage is the #1 anti-exploit failure in Roblox games. Forge writes this with validation by default:

--!strict
local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local CombatRemote = ReplicatedStorage:WaitForChild("Remotes"):WaitForChild("CombatRemote")

local cooldowns: { [number]: number } = {}
local DAMAGE = 18
local COOLDOWN = 0.45
local RANGE = 8

CombatRemote.OnServerEvent:Connect(function(player, targetUserId)
    local now = tick()
    if cooldowns[player.UserId] and now - cooldowns[player.UserId] < COOLDOWN then return end
    local attacker = player.Character and player.Character:FindFirstChild("HumanoidRootPart")
    local target = Players:GetPlayerByUserId(targetUserId)
    local victim = target and target.Character and target.Character:FindFirstChild("HumanoidRootPart")
    if not attacker or not victim then return end
    if (attacker.Position - victim.Position).Magnitude > RANGE then return end
    cooldowns[player.UserId] = now
    local humanoid = victim.Parent:FindFirstChildOfClass("Humanoid")
    if humanoid then humanoid:TakeDamage(DAMAGE) end
end)

Three checks before any damage applies: cooldown (no spam), valid targets (attacker and victim both have HumanoidRootPart), and range (attacker within 8 studs of target). The client only fires the remote with a target ID — all damage math runs server-side.

CombatClient.lua — input + animation

The client script handles the swing animation and fires the remote when the sword connects. Forge's version uses Tool.Activated as the trigger and a magnitude check to find the closest valid target:

--!strict
local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local CombatRemote = ReplicatedStorage:WaitForChild("Remotes"):WaitForChild("CombatRemote")

local player = Players.LocalPlayer
local tool: Tool? = nil

local function onActivated()
    local char = player.Character
    local hrp = char and char:FindFirstChild("HumanoidRootPart")
    if not hrp then return end
    -- Find closest other player within 8 studs
    local closest, closestDist = nil, math.huge
    for _, p in Players:GetPlayers() do
        if p == player then continue end
        local theirChar = p.Character
        local theirHrp = theirChar and theirChar:FindFirstChild("HumanoidRootPart")
        if theirHrp then
            local d = (hrp.Position - theirHrp.Position).Magnitude
            if d < closestDist and d <= 8 then closest, closestDist = p, d end
        end
    end
    if closest then CombatRemote:FireServer(closest.UserId) end
end

player.CharacterAdded:Connect(function(char)
    char.ChildAdded:Connect(function(child)
        if child:IsA("Tool") and child.Name == "ClassicSword" then
            tool = child
            child.Activated:Connect(onActivated)
        end
    end)
end)

Why it works on first try

Three things keep this from being a "compile in tester, fail in Studio" wall of code:

• **Type-safe.** Both scripts ship --!strict with proper type annotations on tables and parameters. luau-lsp catches mistakes before they ship.
• No client trust. Damage, cooldown, range — all validated server-side. The client only sends "I want to hit this target."
• **Real services referenced.** Forge reads your hierarchy on every prompt. ReplicatedStorage:WaitForChild("Remotes") works because Forge created the folder and RemoteEvent in the same generation.

What you'd add manually after

• **Animation.** Tool ships without a swing animation by default; load rbxassetid://507770239 or your own.
• Sound effects. Hit / miss / equip sounds.
• Visual hit feedback. Forge ships pooled DamageNumbers but doesn't add hit sparks.
• Balance. Damage and cooldown numbers are starter values.

These are 30-minute polish jobs, not core architecture. The combat skeleton is in.

Run cost

A combat system for under a dime. Free tier ships with 20 credits — that's four full systems for free.

Try it

Sign up for 20 free credits. Install the Forge AI plugin inside Roblox Studio. Type the same prompt above, get the same five-file output. Compare with whatever you'd get from copy-paste-ChatGPT after 30 minutes of integration work.

For more on the broader plugin, see the Luau generator overview or the game builder page.

Related system guides

• How to make a Roblox combat system — the deep dive on this exact prompt
• How to make a Roblox FPS — server-authoritative hit re-cast, ammo, recoil
• How to make a Roblox boss fight — phase transitions, telegraphs, loot
• How to prevent exploits in Roblox — server-authoritative patterns

Browse all 12 system guides.