diff --git a/packages/core/src/tools/diffOptions.test.ts b/packages/core/src/tools/diffOptions.test.ts
index 95c3beb409..f8fad86381 100644
--- a/packages/core/src/tools/diffOptions.test.ts
+++ b/packages/core/src/tools/diffOptions.test.ts
@@ -18,12 +18,16 @@ describe('getDiffStat', () => {
     expect(diffStat).toEqual({
       ai_added_lines: 0,
       ai_removed_lines: 0,
+      model_added_chars: 0,
+      model_removed_chars: 0,
       user_added_lines: 0,
       user_removed_lines: 0,
+      user_added_chars: 0,
+      user_removed_chars: 0,
     });
   });
 
-  it('should correctly report AI additions', () => {
+  it('should correctly report model additions', () => {
     const oldStr = 'line1\nline2\n';
     const aiStr = 'line1\nline2\nline3\n';
     const userStr = 'line1\nline2\nline3\n';
@@ -31,12 +35,16 @@ describe('getDiffStat', () => {
     expect(diffStat).toEqual({
       ai_added_lines: 1,
       ai_removed_lines: 0,
+      model_added_chars: 5,
+      model_removed_chars: 0,
       user_added_lines: 0,
       user_removed_lines: 0,
+      user_added_chars: 0,
+      user_removed_chars: 0,
     });
   });
 
-  it('should correctly report AI removals', () => {
+  it('should correctly report model removals', () => {
     const oldStr = 'line1\nline2\nline3\n';
     const aiStr = 'line1\nline3\n';
     const userStr = 'line1\nline3\n';
@@ -44,12 +52,16 @@ describe('getDiffStat', () => {
     expect(diffStat).toEqual({
       ai_added_lines: 0,
       ai_removed_lines: 1,
+      model_added_chars: 0,
+      model_removed_chars: 5,
       user_added_lines: 0,
       user_removed_lines: 0,
+      user_added_chars: 0,
+      user_removed_chars: 0,
     });
   });
 
-  it('should correctly report AI modifications', () => {
+  it('should correctly report model modifications', () => {
     const oldStr = 'line1\nline2\nline3\n';
     const aiStr = 'line1\nline_two\nline3\n';
     const userStr = 'line1\nline_two\nline3\n';
@@ -57,8 +69,12 @@ describe('getDiffStat', () => {
     expect(diffStat).toEqual({
       ai_added_lines: 1,
       ai_removed_lines: 1,
+      model_added_chars: 8,
+      model_removed_chars: 5,
       user_added_lines: 0,
       user_removed_lines: 0,
+      user_added_chars: 0,
+      user_removed_chars: 0,
     });
   });
 
@@ -70,8 +86,12 @@ describe('getDiffStat', () => {
     expect(diffStat).toEqual({
       ai_added_lines: 1,
       ai_removed_lines: 0,
+      model_added_chars: 5,
+      model_removed_chars: 0,
       user_added_lines: 1,
       user_removed_lines: 0,
+      user_added_chars: 5,
+      user_removed_chars: 0,
     });
   });
 
@@ -83,8 +103,12 @@ describe('getDiffStat', () => {
     expect(diffStat).toEqual({
       ai_added_lines: 1,
       ai_removed_lines: 0,
+      model_added_chars: 5,
+      model_removed_chars: 0,
       user_added_lines: 0,
       user_removed_lines: 1,
+      user_added_chars: 0,
+      user_removed_chars: 5,
     });
   });
 
@@ -96,12 +120,16 @@ describe('getDiffStat', () => {
     expect(diffStat).toEqual({
       ai_added_lines: 1,
       ai_removed_lines: 0,
+      model_added_chars: 5,
+      model_removed_chars: 0,
       user_added_lines: 1,
       user_removed_lines: 1,
+      user_added_chars: 10,
+      user_removed_chars: 5,
     });
   });
 
-  it('should handle complex changes from both AI and user', () => {
+  it('should handle complex changes from both model and user', () => {
     const oldStr = 'line1\nline2\nline3\nline4\n';
     const aiStr = 'line_one\nline2\nline_three\nline4\n';
     const userStr = 'line_one\nline_two\nline_three\nline4\nline5\n';
@@ -109,8 +137,12 @@ describe('getDiffStat', () => {
     expect(diffStat).toEqual({
       ai_added_lines: 2,
       ai_removed_lines: 2,
+      model_added_chars: 18,
+      model_removed_chars: 10,
       user_added_lines: 2,
       user_removed_lines: 1,
+      user_added_chars: 13,
+      user_removed_chars: 5,
     });
   });
 
@@ -122,8 +154,12 @@ describe('getDiffStat', () => {
     expect(diffStat).toEqual({
       ai_added_lines: 1,
       ai_removed_lines: 1,
+      model_added_chars: 14,
+      model_removed_chars: 11,
       user_added_lines: 0,
       user_removed_lines: 0,
+      user_added_chars: 0,
+      user_removed_chars: 0,
     });
   });
 });
diff --git a/packages/core/src/tools/diffOptions.ts b/packages/core/src/tools/diffOptions.ts
index f49ca611fb..9e418ec2b4 100644
--- a/packages/core/src/tools/diffOptions.ts
+++ b/packages/core/src/tools/diffOptions.ts
@@ -18,22 +18,27 @@ export function getDiffStat(
   aiStr: string,
   userStr: string,
 ): DiffStat {
-  const countLines = (patch: Diff.ParsedDiff) => {
-    let added = 0;
-    let removed = 0;
+  const getStats = (patch: Diff.ParsedDiff) => {
+    let addedLines = 0;
+    let removedLines = 0;
+    let addedChars = 0;
+    let removedChars = 0;
+
     patch.hunks.forEach((hunk: Diff.Hunk) => {
       hunk.lines.forEach((line: string) => {
         if (line.startsWith('+')) {
-          added++;
+          addedLines++;
+          addedChars += line.length - 1;
         } else if (line.startsWith('-')) {
-          removed++;
+          removedLines++;
+          removedChars += line.length - 1;
         }
       });
     });
-    return { added, removed };
+    return { addedLines, removedLines, addedChars, removedChars };
   };
 
-  const patch = Diff.structuredPatch(
+  const modelPatch = Diff.structuredPatch(
     fileName,
     fileName,
     oldStr,
@@ -42,7 +47,7 @@ export function getDiffStat(
     'Proposed',
     DEFAULT_DIFF_OPTIONS,
   );
-  const { added: aiAddedLines, removed: aiRemovedLines } = countLines(patch);
+  const modelStats = getStats(modelPatch);
 
   const userPatch = Diff.structuredPatch(
     fileName,
@@ -53,13 +58,16 @@ export function getDiffStat(
     'User',
     DEFAULT_DIFF_OPTIONS,
   );
-  const { added: userAddedLines, removed: userRemovedLines } =
-    countLines(userPatch);
+  const userStats = getStats(userPatch);
 
   return {
-    ai_added_lines: aiAddedLines,
-    ai_removed_lines: aiRemovedLines,
-    user_added_lines: userAddedLines,
-    user_removed_lines: userRemovedLines,
+    ai_added_lines: modelStats.addedLines,
+    ai_removed_lines: modelStats.removedLines,
+    model_added_chars: modelStats.addedChars,
+    model_removed_chars: modelStats.removedChars,
+    user_added_lines: userStats.addedLines,
+    user_removed_lines: userStats.removedLines,
+    user_added_chars: userStats.addedChars,
+    user_removed_chars: userStats.removedChars,
   };
 }
diff --git a/packages/core/src/tools/edit.test.ts b/packages/core/src/tools/edit.test.ts
index a25f1e8419..5ff4bd4343 100644
--- a/packages/core/src/tools/edit.test.ts
+++ b/packages/core/src/tools/edit.test.ts
@@ -530,8 +530,12 @@ describe('EditTool', () => {
       expect((result.returnDisplay as FileDiff).diffStat).toStrictEqual({
         ai_added_lines: 3,
         ai_removed_lines: 3,
+        model_added_chars: 24,
+        model_removed_chars: 24,
         user_added_lines: 0,
         user_removed_lines: 0,
+        user_added_chars: 0,
+        user_removed_chars: 0,
       });
     });
 
@@ -591,8 +595,12 @@ describe('EditTool', () => {
       expect((result.returnDisplay as FileDiff).diffStat).toStrictEqual({
         ai_added_lines: 1,
         ai_removed_lines: 1,
+        model_added_chars: 7,
+        model_removed_chars: 8,
         user_added_lines: 1,
         user_removed_lines: 1,
+        user_added_chars: 8,
+        user_removed_chars: 7,
       });
     });
 
diff --git a/packages/core/src/tools/tools.ts b/packages/core/src/tools/tools.ts
index 5a61fecdc4..10e67f0205 100644
--- a/packages/core/src/tools/tools.ts
+++ b/packages/core/src/tools/tools.ts
@@ -443,10 +443,14 @@ export interface FileDiff {
 }
 
 export interface DiffStat {
-  ai_removed_lines: number;
   ai_added_lines: number;
+  ai_removed_lines: number;
+  model_added_chars: number;
+  model_removed_chars: number;
   user_added_lines: number;
   user_removed_lines: number;
+  user_added_chars: number;
+  user_removed_chars: number;
 }
 
 export interface ToolEditConfirmationDetails {