Optimize mode export: merge custom prompts before YAML generation

- Add customPrompts parameter to exportModeWithRules() method
- Remove inefficient parse/stringify cycle in webview message handler
- Merge custom prompts directly during export creation instead of post-processing

Author: daniel-lxs

src/core/config/CustomModesManager.ts

@@ -617,9 +617,10 @@ export class CustomModesManager {
 	/**
 	 * Exports a mode configuration with its associated rules files into a shareable YAML format
 	 * @param slug - The mode identifier to export
+	 * @param customPrompts - Optional custom prompts to merge into the export
 	 * @returns Success status with YAML content or error message
 	 */
-	public async exportModeWithRules(slug: string): Promise<ExportResult> {
+	public async exportModeWithRules(slug: string, customPrompts?: any): Promise<ExportResult> {
 		try {
 			// Import modes from shared to check built-in modes
 			const { modes: builtInModes } = await import("../../shared/modes")
@@ -702,6 +703,14 @@ export class CustomModesManager {
 				source: "project" as const,
 			}
 
+			// Merge custom prompts if provided
+			if (customPrompts) {
+				if (customPrompts.roleDefinition) exportMode.roleDefinition = customPrompts.roleDefinition
+				if (customPrompts.description) exportMode.description = customPrompts.description
+				if (customPrompts.whenToUse) exportMode.whenToUse = customPrompts.whenToUse
+				if (customPrompts.customInstructions) exportMode.customInstructions = customPrompts.customInstructions
+			}
+
 			// Add rules files if any exist
 			if (rulesFiles.length > 0) {
 				exportMode.rulesFiles = rulesFiles

src/core/webview/webviewMessageHandler.ts

@@ -1509,32 +1509,10 @@ export const webviewMessageHandler = async (
 					const customModePrompts = getGlobalState("customModePrompts") || {}
 					const customPrompt = customModePrompts[message.slug]
 
-					// Export the mode with any customizations
-					const result = await provider.customModesManager.exportModeWithRules(message.slug)
+					// Export the mode with any customizations merged directly
+					const result = await provider.customModesManager.exportModeWithRules(message.slug, customPrompt)
 
 					if (result.success && result.yaml) {
-						// If there are custom prompts for this mode, merge them into the export
-						if (customPrompt && result.yaml) {
-							try {
-								const exportData = yaml.parse(result.yaml)
-								if (exportData.customModes && exportData.customModes[0]) {
-									// Merge custom prompt data into the mode
-									const mode = exportData.customModes[0]
-									if (customPrompt.roleDefinition) mode.roleDefinition = customPrompt.roleDefinition
-									if (customPrompt.description) mode.description = customPrompt.description
-									if (customPrompt.whenToUse) mode.whenToUse = customPrompt.whenToUse
-									if (customPrompt.customInstructions)
-										mode.customInstructions = customPrompt.customInstructions
-
-									// Re-stringify the updated data
-									result.yaml = yaml.stringify(exportData)
-								}
-							} catch (error) {
-								// If parsing fails, continue with original yaml
-								provider.log(`Failed to merge custom prompts into export: ${error}`)
-							}
-						}
-
 						// Get last used directory for export
 						const lastExportPath = getGlobalState("lastModeExportPath")
 						let defaultUri: vscode.Uri