feat: only require apply_diff for files >25 lines

Add line count check to writeToFileTool to only require apply_diff for files that are more than 25 lines long. This allows write_to_file to work on small existing files while still protecting larger files that need more careful modification.

Signed-off-by: Eric Wheeler <[email protected]>

Author: Eric Wheeler

src/core/tools/writeToFileTool.ts

@@ -1,6 +1,7 @@
 import path from "path"
 import delay from "delay"
 import * as vscode from "vscode"
+import { countFileLines } from "../../integrations/misc/line-counter"
 
 import { Cline } from "../Cline"
 import { ClineSayTool } from "../../shared/ExtensionMessage"
@@ -70,12 +71,18 @@ export async function writeToFileTool(
 	const isOutsideWorkspace = isPathOutsideWorkspace(fullPath)
 
 	if (fileExists) {
-		pushToolResult(
-			formatResponse.toolError(
-				`File '${relPath}' already exists, write_to_file failed: You must use the 'apply_diff' tool to change an existing file.`,
-			),
-		)
-		return
+		// Count the lines in the file
+		const absolutePath = path.resolve(cline.cwd, relPath)
+		const lineCount = await countFileLines(absolutePath)
+		// Only show error if file has more than 25 lines
+		if (lineCount > 25) {
+			pushToolResult(
+				formatResponse.toolError(
+					`File '${relPath}' already exists and is >25 lines long, write_to_file failed: You must use the '<apply_diff>' or '<search_and_replace>' tool to change an existing file.`,
+				),
+			)
+			return
+		}
 	}
 
 	const sharedMessageProps: ClineSayTool = {