diff --git a/comfy_api_nodes/apis/__init__.py b/comfy_api_nodes/apis/__init__.py
index ee2aa1ce6..c1cbd68ea 100644
--- a/comfy_api_nodes/apis/__init__.py
+++ b/comfy_api_nodes/apis/__init__.py
@@ -5749,8 +5749,8 @@ class EasyInputMessage(BaseModel):
 
 
 class GeminiContent(BaseModel):
-    parts: List[GeminiPart]
-    role: Role1 = Field(..., examples=['user'])
+    parts: List[GeminiPart] = Field(default_factory=list)
+    role: Optional[Role1] = Field(None, examples=['user'])
 
 
 class GeminiGenerateContentRequest(BaseModel):
diff --git a/comfy_api_nodes/apis/gemini.py b/comfy_api_nodes/apis/gemini.py
index d81337dae..d65122f14 100644
--- a/comfy_api_nodes/apis/gemini.py
+++ b/comfy_api_nodes/apis/gemini.py
@@ -75,7 +75,7 @@ class GeminiTextPart(BaseModel):
 
 class GeminiContent(BaseModel):
     parts: list[GeminiPart] = Field([])
-    role: GeminiRole = Field(..., examples=["user"])
+    role: GeminiRole | None = Field(None, examples=["user"])
 
 
 class GeminiSystemInstructionContent(BaseModel):
diff --git a/comfy_api_nodes/nodes_gemini.py b/comfy_api_nodes/nodes_gemini.py
index 3b31caa7b..78881c3e9 100644
--- a/comfy_api_nodes/nodes_gemini.py
+++ b/comfy_api_nodes/nodes_gemini.py
@@ -119,6 +119,45 @@ async def create_image_parts(
     return image_parts
 
 
+def _summarize_gemini_response_issues(response: GeminiGenerateContentResponse) -> str:
+    details: list[str] = []
+    if response.promptFeedback and response.promptFeedback.blockReason:
+        msg = f"promptFeedback.blockReason={response.promptFeedback.blockReason}"
+        if response.promptFeedback.blockReasonMessage:
+            msg = f"{msg} ({response.promptFeedback.blockReasonMessage})"
+        details.append(msg)
+
+    finish_reasons = sorted(
+        {
+            candidate.finishReason
+            for candidate in (response.candidates or [])
+            if candidate.finishReason
+        }
+    )
+    if finish_reasons:
+        details.append(f"finishReason(s)={', '.join(finish_reasons)}")
+
+    safety_ratings: set[str] = set()
+    for candidate in response.candidates or []:
+        for rating in candidate.safetyRatings or []:
+            if rating.category and rating.probability:
+                safety_ratings.add(f"{rating.category}:{rating.probability}")
+            elif rating.category:
+                safety_ratings.add(str(rating.category))
+    if safety_ratings:
+        details.append(f"safetyRatings={', '.join(sorted(safety_ratings))}")
+
+    candidates = response.candidates or []
+    if candidates:
+        missing_content = sum(
+            1 for candidate in candidates if candidate.content is None or candidate.content.parts is None
+        )
+        if missing_content:
+            details.append(f"candidates_missing_content={missing_content}/{len(candidates)}")
+
+    return "; ".join(details)
+
+
 def get_parts_by_type(response: GeminiGenerateContentResponse, part_type: Literal["text"] | str) -> list[GeminiPart]:
     """
     Filter response parts by their type.
@@ -156,8 +195,21 @@ def get_parts_by_type(response: GeminiGenerateContentResponse, part_type: Litera
             elif part.fileData and part.fileData.mimeType == part_type:
                 parts.append(part)
 
-    if not parts and blocked_reasons:
-        raise ValueError(f"Gemini API blocked the request. Reasons: {blocked_reasons}")
+    if not parts:
+        if blocked_reasons:
+            raise ValueError(f"Gemini API blocked the request. Reasons: {blocked_reasons}")
+        if part_type == "text":
+            return []
+        details = _summarize_gemini_response_issues(response)
+        if details:
+            raise ValueError(
+                f"Gemini API returned no {part_type} parts. Details: {details}. "
+                "If you are using the `IMAGE` modality, try `IMAGE+TEXT` to see why image generation failed."
+            )
+        raise ValueError(
+            f"Gemini API returned no {part_type} parts. "
+            "If you are using the `IMAGE` modality, try `IMAGE+TEXT` to see why image generation failed."
+        )
 
     return parts
 
@@ -187,7 +239,17 @@ async def get_image_from_response(response: GeminiGenerateContentResponse) -> In
             returned_image = await download_url_to_image_tensor(part.fileData.fileUri)
         image_tensors.append(returned_image)
     if len(image_tensors) == 0:
-        return torch.zeros((1, 1024, 1024, 4))
+        details = _summarize_gemini_response_issues(response)
+        if details:
+            raise ValueError(
+                "Gemini API returned no image parts. "
+                f"Details: {details}. "
+                "If you are using the `IMAGE` modality, try `IMAGE+TEXT` to see why image generation failed."
+            )
+        raise ValueError(
+            "Gemini API returned no image parts. "
+            "If you are using the `IMAGE` modality, try `IMAGE+TEXT` to see why image generation failed."
+        )
     return torch.cat(image_tensors, dim=0)