From 6b9b778d821728427eea07b1b97ba07378137d0b Mon Sep 17 00:00:00 2001
From: Daniel Weis <danielweis@users.noreply.github.com>
Date: Fri, 8 May 2026 15:01:24 -0400
Subject: [PATCH] fix: resolve "function response turn must come immediately
 after function call" error (#26691)

Co-authored-by: Tommaso Sciortino <sciortino@gmail.com>
---
 packages/core/src/core/geminiChat.test.ts | 67 +++++++++++++++++++++++
 packages/core/src/core/geminiChat.ts      | 10 +++-
 2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/packages/core/src/core/geminiChat.test.ts b/packages/core/src/core/geminiChat.test.ts
index 1a54821f52..f689d86a1c 100644
--- a/packages/core/src/core/geminiChat.test.ts
+++ b/packages/core/src/core/geminiChat.test.ts
@@ -2796,4 +2796,71 @@ describe('GeminiChat', () => {
       ]);
     });
   });
+
+  describe('getHistory with curated: true', () => {
+    it('should not drop model turns with function calls and empty text', () => {
+      const history: Content[] = [
+        { role: 'user', parts: [{ text: 'Hello' }] },
+        {
+          role: 'model',
+          parts: [{ functionCall: { name: 'test_tool', args: {} }, text: '' }],
+        },
+        {
+          role: 'user',
+          parts: [{ functionResponse: { name: 'test_tool', response: {} } }],
+        },
+      ];
+      const chatWithHistory = new GeminiChat(mockConfig, '', [], history);
+
+      const curatedHistory = chatWithHistory.getHistory(true);
+
+      expect(curatedHistory.length).toBe(3);
+      expect(curatedHistory[1].role).toBe('model');
+      expect(curatedHistory[1].parts![0].functionCall).toBeDefined();
+    });
+
+    it('should not drop model turns with inlineData and empty text', () => {
+      const history: Content[] = [
+        { role: 'user', parts: [{ text: 'Hello' }] },
+        {
+          role: 'model',
+          parts: [
+            {
+              inlineData: { mimeType: 'image/jpeg', data: 'base64...' },
+              text: '',
+            },
+          ],
+        },
+      ];
+      const chatWithHistory = new GeminiChat(mockConfig, '', [], history);
+
+      const curatedHistory = chatWithHistory.getHistory(true);
+
+      expect(curatedHistory.length).toBe(2);
+      expect(curatedHistory[1].role).toBe('model');
+      expect(curatedHistory[1].parts![0].inlineData).toBeDefined();
+    });
+
+    it('should not drop model turns with fileData and empty text', () => {
+      const history: Content[] = [
+        { role: 'user', parts: [{ text: 'Hello' }] },
+        {
+          role: 'model',
+          parts: [
+            {
+              fileData: { mimeType: 'image/jpeg', fileUri: 'https://...' },
+              text: '',
+            },
+          ],
+        },
+      ];
+      const chatWithHistory = new GeminiChat(mockConfig, '', [], history);
+
+      const curatedHistory = chatWithHistory.getHistory(true);
+
+      expect(curatedHistory.length).toBe(2);
+      expect(curatedHistory[1].role).toBe('model');
+      expect(curatedHistory[1].parts![0].fileData).toBeDefined();
+    });
+  });
 });
diff --git a/packages/core/src/core/geminiChat.ts b/packages/core/src/core/geminiChat.ts
index 398214a028..daa6e9d11b 100644
--- a/packages/core/src/core/geminiChat.ts
+++ b/packages/core/src/core/geminiChat.ts
@@ -146,7 +146,15 @@ function isValidContent(content: Content): boolean {
     if (part === undefined || Object.keys(part).length === 0) {
       return false;
     }
-    if (!part.thought && part.text !== undefined && part.text === '') {
+    if (
+      !part.thought &&
+      !part.functionCall &&
+      !part.functionResponse &&
+      !part.inlineData &&
+      !part.fileData &&
+      part.text !== undefined &&
+      part.text === ''
+    ) {
       return false;
     }
   }