diff --git a/plugin/src/Components/App.lua b/plugin/src/Components/App.lua
index 246b60cd..824f6d10 100644
--- a/plugin/src/Components/App.lua
+++ b/plugin/src/Components/App.lua
@@ -133,7 +133,7 @@ function App:startSession(address, port)
 			-- Details being present indicates that this
 			-- disconnection was from an error.
 			if details ~= nil then
-				Log.warn(tostring(details))
+				Log.warn("Disconnected from an error: {}", details)
 
 				self:setState({
 					appStatus = AppStatus.Error,
@@ -207,7 +207,7 @@ function App:render()
 end
 
 function App:didMount()
-	Log.trace("Rojo %s initializing", self.displayedVersion)
+	Log.trace("Rojo {} initializing", self.displayedVersion)
 
 	checkUpgrade(self.props.plugin)
 	preloadAssets()
diff --git a/plugin/src/InstanceMap.lua b/plugin/src/InstanceMap.lua
index 43476fb3..4c497c0a 100644
--- a/plugin/src/InstanceMap.lua
+++ b/plugin/src/InstanceMap.lua
@@ -20,14 +20,16 @@ function InstanceMap.new(onInstanceChanged)
 	return setmetatable(self, InstanceMap)
 end
 
-function InstanceMap:debugState()
-	local buffer = {}
+function InstanceMap:__fmtDebug(output)
+	output:writeLine("InstanceMap {{")
+	output:indent()
 
 	for id, instance in pairs(self.fromIds) do
-		table.insert(buffer, string.format("- %s: %s", id, instance:GetFullName()))
+		output:writeLine("- {}: {}", id, instance:GetFullName())
 	end
 
-	return table.concat(buffer, "\n")
+	output:unindent()
+	output:writeLine("}")
 end
 
 function InstanceMap:insert(id, instance)
@@ -44,7 +46,7 @@ function InstanceMap:removeId(id)
 		self.fromIds[id] = nil
 		self.fromInstances[instance] = nil
 	else
-		Log.warn("Attempted to remove nonexistant ID %s", tostring(id))
+		Log.warn("Attempted to remove nonexistant ID {}", id)
 	end
 end
 
@@ -56,7 +58,7 @@ function InstanceMap:removeInstance(instance)
 		self.fromInstances[instance] = nil
 		self.fromIds[id] = nil
 	else
-		Log.warn("Attempted to remove nonexistant instance %s", tostring(instance))
+		Log.warn("Attempted to remove nonexistant instance {}", instance)
 	end
 end
 
@@ -66,7 +68,7 @@ function InstanceMap:destroyInstance(instance)
 	if id ~= nil then
 		self:destroyId(id)
 	else
-		Log.warn("Attempted to destroy untracked instance %s", tostring(instance))
+		Log.warn("Attempted to destroy untracked instance {}", instance)
 	end
 end
 
@@ -89,7 +91,7 @@ function InstanceMap:destroyId(id)
 
 		instance:Destroy()
 	else
-		Log.warn("Attempted to destroy nonexistant ID %s", tostring(id))
+		Log.warn("Attempted to destroy nonexistant ID {}", id)
 	end
 end
 
diff --git a/plugin/src/Reconciler.lua b/plugin/src/Reconciler.lua
index 7ab35cb6..7bffa2b4 100644
--- a/plugin/src/Reconciler.lua
+++ b/plugin/src/Reconciler.lua
@@ -134,10 +134,10 @@ function Reconciler:applyPatch(patch)
 
 			if parentInstance == nil then
 				invariant(
-					"Cannot add an instance from a patch that has no parent.\nInstance %s with parent %s.\nInstanceMap state:\n%s",
+					"Cannot add an instance from a patch that has no parent.\nInstance {} with parent {}.\nState: {:#?}",
 					id,
-					tostring(apiInstance.Parent),
-					self.__instanceMap:debugState()
+					apiInstance.Parent,
+					self.__instanceMap
 				)
 			end
 
@@ -150,9 +150,9 @@ function Reconciler:applyPatch(patch)
 
 		if instance == nil then
 			invariant(
-				"Cannot update an instance that does not exist in the reconciler's state.\nInstance ID %s\nInstanceMap state:\n%s",
+				"Cannot update an instance that does not exist in the reconciler's state.\nInstance {}\nState: {:#?}",
 				update.id,
-				self.__instanceMap:debugState()
+				self.__instanceMap
 			)
 		end
 
diff --git a/plugin/src/invariant.lua b/plugin/src/invariant.lua
index 3923095b..7cb813b4 100644
--- a/plugin/src/invariant.lua
+++ b/plugin/src/invariant.lua
@@ -1,16 +1,18 @@
+local Fmt = require(script.Parent.Parent.Fmt)
+
 local Config = require(script.Parent.Config)
 
 local invariant
 
 if Config.isDevBuild then
 	function invariant(message, ...)
-		message = string.format(message, ...)
+		message = Fmt.fmt(message, ...)
 
 		error("Invariant violation: " .. message, 2)
 	end
 else
 	function invariant(message, ...)
-		message = string.format(message, ...)
+		message = Fmt.fmt(message, ...)
 
 		local fullMessage = string.format(
 			"Rojo detected an invariant violation within itself:\n" ..
diff --git a/plugin/src/preloadAssets.lua b/plugin/src/preloadAssets.lua
index a8a4a4f1..c23d2dd1 100644
--- a/plugin/src/preloadAssets.lua
+++ b/plugin/src/preloadAssets.lua
@@ -19,7 +19,7 @@ local function preloadAssets()
 		table.insert(contentUrls, url)
 	end
 
-	Log.trace("Preloading assets: %s", table.concat(contentUrls, ", "))
+	Log.trace("Preloading assets: {:?}", contentUrls)
 
 	coroutine.wrap(function()
 		ContentProvider:PreloadAsync(contentUrls)