feat: add prepend_to_file tool for prepending content to files

src/core/Cline.ts

@@ -79,6 +79,7 @@ import { switchModeTool } from "./tools/switchModeTool"
 import { attemptCompletionTool } from "./tools/attemptCompletionTool"
 import { newTaskTool } from "./tools/newTaskTool"
 import { appendToFileTool } from "./tools/appendToFileTool"
+import { prependToFileTool } from "./tools/prependToFileTool"
 
 // prompts
 import { formatResponse } from "./prompts/responses"
@@ -1242,6 +1243,8 @@ export class Cline extends EventEmitter<ClineEvents> {
 							return `[${block.name} for '${block.params.path}']`
 						case "append_to_file":
 							return `[${block.name} for '${block.params.path}']`
+						case "prepend_to_file":
+							return `[${block.name} for '${block.params.path}']`
 						case "apply_diff":
 							return `[${block.name} for '${block.params.path}']`
 						case "search_files":
@@ -1429,6 +1432,9 @@ export class Cline extends EventEmitter<ClineEvents> {
 					case "append_to_file":
 						await appendToFileTool(this, block, askApproval, handleError, pushToolResult, removeClosingTag)
 						break
+					case "prepend_to_file":
+						await prependToFileTool(this, block, askApproval, handleError, pushToolResult, removeClosingTag)
+						break
 					case "apply_diff":
 						await applyDiffTool(this, block, askApproval, handleError, pushToolResult, removeClosingTag)
 						break

src/core/prompts/sections/rules.ts

@@ -14,7 +14,10 @@ function getEditingInstructions(diffStrategy?: DiffStrategy, experiments?: Recor
 		availableTools.push("write_to_file (for creating new files or complete file rewrites)")
 	}
 
-	availableTools.push("append_to_file (for appending content to the end of files)")
+	availableTools.push(
+		"append_to_file (for appending content to the end of files)",
+		"prepend_to_file (for prepending content to the beginning of files)"
+	)
 
 	if (experiments?.["insert_content"]) {
 		availableTools.push("insert_content (for adding lines to existing files)")
@@ -28,6 +31,7 @@ function getEditingInstructions(diffStrategy?: DiffStrategy, experiments?: Recor
 		instructions.push(
 			`- For editing files, you have access to these tools: ${availableTools.join(", ")}.`,
 			"- The append_to_file tool adds content to the end of files, such as appending new log entries or adding new data records. This tool will always add the content at the end of the file.",
+			"- The prepend_to_file tool adds content to the beginning of files, such as adding license headers, import statements, or configuration headers. This tool will always add the content at the beginning of the file, before any existing content. Use this tool when adding content that logically belongs at the top of a file.",
 		)
 	}
 

src/core/prompts/tools/index.ts

@@ -9,6 +9,7 @@ import { getReadFileDescription } from "./read-file"
 import { getFetchInstructionsDescription } from "./fetch-instructions"
 import { getWriteToFileDescription } from "./write-to-file"
 import { getAppendToFileDescription } from "./append-to-file"
+import { getPrependToFileDescription } from "./prepend-to-file"
 import { getSearchFilesDescription } from "./search-files"
 import { getListFilesDescription } from "./list-files"
 import { getInsertContentDescription } from "./insert-content"
@@ -29,6 +30,7 @@ const toolDescriptionMap: Record<string, (args: ToolArgs) => string | undefined>
 	fetch_instructions: () => getFetchInstructionsDescription(),
 	write_to_file: (args) => getWriteToFileDescription(args),
 	append_to_file: (args) => getAppendToFileDescription(args),
+	prepend_to_file: (args) => getPrependToFileDescription(args),
 	search_files: (args) => getSearchFilesDescription(args),
 	list_files: (args) => getListFilesDescription(args),
 	list_code_definition_names: (args) => getListCodeDefinitionNamesDescription(args),
@@ -114,6 +116,7 @@ export {
 	getFetchInstructionsDescription,
 	getWriteToFileDescription,
 	getAppendToFileDescription,
+	getPrependToFileDescription,
 	getSearchFilesDescription,
 	getListFilesDescription,
 	getListCodeDefinitionNamesDescription,

src/core/prompts/tools/prepend-to-file.ts

@@ -0,0 +1,41 @@
+import { ToolArgs } from "./types"
+
+export function getPrependToFileDescription(args: ToolArgs): string {
+	return `## prepend_to_file
+Description: Request to prepend content to a file at the specified path. If the file exists, the content will be added to the beginning of the file. If the file doesn't exist, it will be created with the provided content. This tool will automatically create any directories needed to write the file.
+Parameters:
+- path: (required) The path of the file to prepend to (relative to the current workspace directory ${args.cwd})
+- content: (required) The content to prepend to the file. The content will be added at the beginning of the existing file content. Do NOT include line numbers in the content.
+Usage:
+<prepend_to_file>
+<path>File path here</path>
+<content>
+Your content to prepend here
+</content>
+</prepend_to_file>
+
+Example: Requesting to prepend a license header
+<prepend_to_file>
+<path>src/index.js</path>
+<content>
+/**
+ * Copyright (c) 2025 Roo Veterinary Inc.
+ * 
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+</content>
+</prepend_to_file>
+
+Example: Requesting to prepend import statements
+<prepend_to_file>
+<path>src/components/Button.js</path>
+<content>
+import React from 'react';
+import PropTypes from 'prop-types';
+import './Button.css';
+
+</content>
+</prepend_to_file>`
+}