diff --git a/client/src/common/handlers.ts b/client/src/common/handlers.ts
index 7627b76..542f899 100644
--- a/client/src/common/handlers.ts
+++ b/client/src/common/handlers.ts
@@ -12,10 +12,29 @@ export function formatCdlFile(content: string): string {
         if (strippedLine.endsWith("{")) {
             indentLevel += 1
         }
+        if (strippedLine.startsWith("#")) {
+            formattedLines[formattedLines.length - 1] =
+                "    ".repeat(indentLevel) + strippedLine.replace(/^#\s*/, "# ")
+        }
     }
     return formattedLines.join("\n")
 }
 
+export function formatDefFile(content: string): string {
+    let indentLevel = 0
+    const formattedLines = []
+    for (const line of content.split("\n")) {
+        const strippedLine = line.trim()
+        if (strippedLine.endsWith("}")) {
+            indentLevel = Math.max(indentLevel - 1, 0)
+        }
+        formattedLines.push("    ".repeat(indentLevel) + strippedLine)
+        if (strippedLine.endsWith("{")) {
+            indentLevel += 1
+        }
+    }
+    return formattedLines.join("\n")
+}
 export function completionHandlerCdl(document: vscode.TextDocument, position: vscode.Position) {
     const linePrefix = document.lineAt(position).text.substring(0, position.character)
     const categories = ["MILL", "LATHE", "DRILL"]
diff --git a/client/src/extension.ts b/client/src/extension.ts
index a99bb04..a98b6ca 100644
--- a/client/src/extension.ts
+++ b/client/src/extension.ts
@@ -1,5 +1,10 @@
 import * as vscode from "vscode"
-import { formatCdlFile, completionHandlerCdl, hoverCdlHandler } from "./common/handlers"
+import {
+    formatCdlFile,
+    completionHandlerCdl,
+    hoverCdlHandler,
+    formatDefFile
+} from "./common/handlers"
 
 export function activate(context: vscode.ExtensionContext) {
     const formatCdlProvider = vscode.languages.registerDocumentFormattingEditProvider(
@@ -48,6 +53,23 @@ export function activate(context: vscode.ExtensionContext) {
         }
     )
     context.subscriptions.push(hoverCdlProvider)
+
+    const formatDefProvider = vscode.languages.registerDocumentFormattingEditProvider(
+        { scheme: "file", language: "def" },
+        {
+            provideDocumentFormattingEdits(document: vscode.TextDocument): vscode.TextEdit[] {
+                const text = document.getText()
+                const formattedText = formatDefFile(text)
+                const fullRange = new vscode.Range(
+                    document.positionAt(0),
+                    document.positionAt(text.length)
+                )
+                return [vscode.TextEdit.replace(fullRange, formattedText)]
+            }
+        }
+    )
+
+    context.subscriptions.push(formatDefProvider)
 }
 
 export function deactivate() {}