From 047a57dee831ba8ba287eee2637ba791dd3d4586 Mon Sep 17 00:00:00 2001
From: Christian Gunderman <gundermanc@google.com>
Date: Tue, 17 Feb 2026 19:31:57 -0800
Subject: [PATCH] feat(core): Include file content in write_file tool response
 for immediate verification

---
 packages/core/src/tools/write-file.test.ts | 14 ++++++++++++++
 packages/core/src/tools/write-file.ts      |  2 ++
 2 files changed, 16 insertions(+)

diff --git a/packages/core/src/tools/write-file.test.ts b/packages/core/src/tools/write-file.test.ts
index 3545affe3f..b26b0b1b3f 100644
--- a/packages/core/src/tools/write-file.test.ts
+++ b/packages/core/src/tools/write-file.test.ts
@@ -831,6 +831,20 @@ describe('WriteFileTool', () => {
         }
       },
     );
+
+    it('should include the file content in llmContent', async () => {
+      const filePath = path.join(rootDir, 'content_check.txt');
+      const content = 'This is the content that should be returned.';
+      mockEnsureCorrectFileContent.mockResolvedValue(content);
+
+      const params = { file_path: filePath, content };
+      const invocation = tool.build(params);
+
+      const result = await invocation.execute(abortSignal);
+
+      expect(result.llmContent).toContain('Here is the updated code:');
+      expect(result.llmContent).toContain(content);
+    });
   });
 
   describe('workspace boundary validation', () => {
diff --git a/packages/core/src/tools/write-file.ts b/packages/core/src/tools/write-file.ts
index 9f4abfdf55..b46f424557 100644
--- a/packages/core/src/tools/write-file.ts
+++ b/packages/core/src/tools/write-file.ts
@@ -356,6 +356,8 @@ class WriteFileToolInvocation extends BaseToolInvocation<
         );
       }
 
+      llmSuccessMessageParts.push(`Here is the updated code:\n${finalContent}`);
+
       // Log file operation for telemetry (without diff_stat to avoid double-counting)
       const mimetype = getSpecificMimeType(this.resolvedPath);
       const programmingLanguage = getLanguageFromFilePath(this.resolvedPath);