fix: update parseAssistantMessage and parseAssistantMessageV2 to preserve newlines in content parameters while stripping leading and trailing newlines

Author: daniel-lxs

src/core/assistant-message/parseAssistantMessage.ts

@@ -24,10 +24,12 @@ export function parseAssistantMessage(assistantMessage: string): AssistantMessag
 			const paramClosingTag = `</${currentParamName}>`
 			if (currentParamValue.endsWith(paramClosingTag)) {
 				// End of param value.
-				// Don't trim content parameters to preserve newlines
+				// Don't trim content parameters to preserve newlines, but strip first and last newline only
 				const paramValue = currentParamValue.slice(0, -paramClosingTag.length)
 				currentToolUse.params[currentParamName] =
-					currentParamName === "content" ? paramValue : paramValue.trim()
+					currentParamName === "content"
+						? paramValue.replace(/^\n/, "").replace(/\n$/, "")
+						: paramValue.trim()
 				currentParamName = undefined
 				continue
 			} else {
@@ -75,8 +77,11 @@ export function parseAssistantMessage(assistantMessage: string): AssistantMessag
 					const contentEndIndex = toolContent.lastIndexOf(contentEndTag)
 
 					if (contentStartIndex !== -1 && contentEndIndex !== -1 && contentEndIndex > contentStartIndex) {
-						// Don't trim content to preserve newlines
-						currentToolUse.params[contentParamName] = toolContent.slice(contentStartIndex, contentEndIndex)
+						// Don't trim content to preserve newlines, but strip first and last newline only
+						currentToolUse.params[contentParamName] = toolContent
+							.slice(contentStartIndex, contentEndIndex)
+							.replace(/^\n/, "")
+							.replace(/\n$/, "")
 					}
 				}
 
@@ -140,9 +145,10 @@ export function parseAssistantMessage(assistantMessage: string): AssistantMessag
 		// Stream did not complete tool call, add it as partial.
 		if (currentParamName) {
 			// Tool call has a parameter that was not completed.
-			// Don't trim content parameters to preserve newlines
+			// Don't trim content parameters to preserve newlines, but strip first and last newline only
 			const paramValue = accumulator.slice(currentParamValueStartIndex)
-			currentToolUse.params[currentParamName] = currentParamName === "content" ? paramValue : paramValue.trim()
+			currentToolUse.params[currentParamName] =
+				currentParamName === "content" ? paramValue.replace(/^\n/, "").replace(/\n$/, "") : paramValue.trim()
 		}
 
 		contentBlocks.push(currentToolUse)

src/core/assistant-message/parseAssistantMessageV2.ts

@@ -80,8 +80,9 @@ export function parseAssistantMessageV2(assistantMessage: string): AssistantMess
 					currentParamValueStart, // Start after the opening tag.
 					currentCharIndex - closeTag.length + 1, // End before the closing tag.
 				)
-				// Don't trim content parameters to preserve newlines
-				currentToolUse.params[currentParamName] = currentParamName === "content" ? value : value.trim()
+				// Don't trim content parameters to preserve newlines, but strip first and last newline only
+				currentToolUse.params[currentParamName] =
+					currentParamName === "content" ? value.replace(/^\n/, "").replace(/\n$/, "") : value.trim()
 				currentParamName = undefined // Go back to parsing tool content.
 				// We don't continue loop here, need to check for tool close or other params at index i.
 			} else {
@@ -145,8 +146,11 @@ export function parseAssistantMessageV2(assistantMessage: string): AssistantMess
 					const contentEnd = toolContentSlice.lastIndexOf(contentEndTag)
 
 					if (contentStart !== -1 && contentEnd !== -1 && contentEnd > contentStart) {
-						// Don't trim content to preserve newlines
-						const contentValue = toolContentSlice.slice(contentStart + contentStartTag.length, contentEnd)
+						// Don't trim content to preserve newlines, but strip first and last newline only
+						const contentValue = toolContentSlice
+							.slice(contentStart + contentStartTag.length, contentEnd)
+							.replace(/^\n/, "")
+							.replace(/\n$/, "")
 						currentToolUse.params[contentParamName] = contentValue
 					}
 				}
@@ -249,8 +253,9 @@ export function parseAssistantMessageV2(assistantMessage: string): AssistantMess
 	// Finalize any open parameter within an open tool use.
 	if (currentToolUse && currentParamName) {
 		const value = assistantMessage.slice(currentParamValueStart) // From param start to end of string.
-		// Don't trim content parameters to preserve newlines
-		currentToolUse.params[currentParamName] = currentParamName === "content" ? value : value.trim()
+		// Don't trim content parameters to preserve newlines, but strip first and last newline only
+		currentToolUse.params[currentParamName] =
+			currentParamName === "content" ? value.replace(/^\n/, "").replace(/\n$/, "") : value.trim()
 		// Tool use remains partial.
 	}