feat: pass Edit code diff start line in tool return (#994)

src/cli/components/ToolCallMessageRich.tsx

@@ -233,10 +233,29 @@ export const ToolCallMessage = memo(
     const dotShouldAnimate =
       line.phase === "running" || (line.phase === "ready" && !isStreaming);
 
+    // Extract display text from tool result (handles JSON responses)
+    const extractMessageFromResult = (text: string): string => {
+      try {
+        const parsed = JSON.parse(text);
+        // If it's a JSON object with a message field, extract that
+        if (
+          parsed &&
+          typeof parsed === "object" &&
+          typeof parsed.message === "string"
+        ) {
+          return parsed.message;
+        }
+      } catch {
+        // Not JSON or parsing failed, use as-is
+      }
+      return text;
+    };
+
     // Format result for display
     const getResultElement = () => {
       if (!line.resultText) return null;
 
+      const extractedText = extractMessageFromResult(line.resultText);
       const prefix = `  ⎿  `; // Match old format: 2 spaces, glyph, 2 spaces
       const prefixWidth = 5; // Total width of prefix
       const contentWidth = Math.max(0, columns - prefixWidth);
@@ -270,7 +289,7 @@ export const ToolCallMessage = memo(
 
       // Truncate the result text for display (UI only, API gets full response)
       // Strip trailing newlines to avoid extra visual spacing (e.g., from bash echo)
-      const displayResultText = clipToolReturn(line.resultText).replace(
+      const displayResultText = clipToolReturn(extractedText).replace(
         /\n+$/,
         "",
       );

src/tools/impl/Edit.ts

@@ -12,6 +12,7 @@ interface EditArgs {
 interface EditResult {
   message: string;
   replacements: number;
+  startLine?: number;
 }
 
 function countOccurrences(content: string, needle: string): number {
@@ -184,13 +185,22 @@ export async function edit(args: EditArgs): Promise<EditResult> {
       (expected_replacements !== undefined && expected_replacements > 1);
     let newContent: string;
     let replacements: number;
+    let startLine: number | undefined;
+
     if (effectiveReplaceAll) {
       newContent = content.split(finalOldString).join(finalNewString);
       replacements = occurrences;
+      // For replace_all, calculate line number of first occurrence
+      const firstIndex = content.indexOf(finalOldString);
+      if (firstIndex !== -1) {
+        startLine = content.substring(0, firstIndex).split("\n").length;
+      }
     } else {
       const index = content.indexOf(finalOldString);
       if (index === -1)
         throw new Error(`String not found in file: ${finalOldString}`);
+      // Calculate the line number where old_string starts (1-indexed)
+      startLine = content.substring(0, index).split("\n").length;
       newContent =
         content.substring(0, index) +
         finalNewString +
@@ -198,9 +208,11 @@ export async function edit(args: EditArgs): Promise<EditResult> {
       replacements = 1;
     }
     await fs.writeFile(resolvedPath, newContent, "utf-8");
+
     return {
       message: `Successfully replaced ${replacements} occurrence${replacements !== 1 ? "s" : ""} in ${resolvedPath}`,
       replacements,
+      startLine,
     };
   } catch (error) {
     const err = error as NodeJS.ErrnoException;

src/tools/impl/MultiEdit.ts

@@ -11,9 +11,15 @@ export interface MultiEditArgs {
   file_path: string;
   edits: Edit[];
 }
+interface EditWithLine {
+  description: string;
+  startLine: number;
+}
+
 interface MultiEditResult {
   message: string;
   edits_applied: number;
+  edits: EditWithLine[];
 }
 
 export async function multi_edit(
@@ -45,7 +51,7 @@ export async function multi_edit(
     const rawContent = await fs.readFile(resolvedPath, "utf-8");
     // Normalize line endings to LF for consistent matching (Windows uses CRLF)
     let content = rawContent.replace(/\r\n/g, "\n");
-    const appliedEdits: string[] = [];
+    const appliedEdits: EditWithLine[] = [];
     for (let i = 0; i < edits.length; i++) {
       const edit = edits[i];
       if (!edit) continue;
@@ -61,26 +67,33 @@ export async function multi_edit(
           `Found ${occurrences} matches of the string to replace, but replace_all is false. To replace all occurrences, set replace_all to true. To replace only one occurrence, please provide more context to uniquely identify the instance.\nString: ${old_string}`,
         );
       }
+
+      // Calculate start line before applying the edit
+      const index = content.indexOf(old_string);
+      const startLine = content.substring(0, index).split("\n").length;
+
       if (replace_all) {
         content = content.split(old_string).join(new_string);
       } else {
-        const index = content.indexOf(old_string);
         content =
           content.substring(0, index) +
           new_string +
           content.substring(index + old_string.length);
       }
-      appliedEdits.push(
-        `Replaced "${old_string.substring(0, 50)}${old_string.length > 50 ? "..." : ""}" with "${new_string.substring(0, 50)}${new_string.length > 50 ? "..." : ""}"`,
-      );
+      appliedEdits.push({
+        description: `Replaced "${old_string.substring(0, 50)}${old_string.length > 50 ? "..." : ""}" with "${new_string.substring(0, 50)}${new_string.length > 50 ? "..." : ""}"`,
+        startLine,
+      });
     }
     await fs.writeFile(resolvedPath, content, "utf-8");
     const editList = appliedEdits
-      .map((edit, i) => `${i + 1}. ${edit}`)
+      .map((edit, i) => `${i + 1}. ${edit.description}`)
       .join("\n");
+
     return {
       message: `Applied ${edits.length} edit${edits.length !== 1 ? "s" : ""} to ${resolvedPath}:\n${editList}`,
       edits_applied: edits.length,
+      edits: appliedEdits,
     };
   } catch (error) {
     const err = error as NodeJS.ErrnoException;

src/tools/manager.ts

@@ -949,6 +949,12 @@ function flattenToolResponse(result: unknown): ToolReturnContent {
   }
 
   if (typeof result.message === "string") {
+    // If there are other fields besides 'message', return the full object as JSON
+
+    const keys = Object.keys(result);
+    if (keys.length > 1) {
+      return JSON.stringify(result);
+    }
     return result.message;
   }