fix: update default VLM model from deprecated gemini-2.0-flash to gemini-2.5-flash

The gemini-2.0-flash model has been deprecated by Google and returns
404 NOT_FOUND for new users. This updates all default references to
gemini-2.5-flash across config, provider, tests, examples, and docs.

Fixes #44

Author: haosenwang1018

README.md

@@ -137,7 +137,7 @@ PaperBanana supports multiple VLM and image generation providers:
 |-----------|----------|-------|-------|
 | VLM (planning, critique) | OpenAI | `gpt-5.2` | Default |
 | Image Generation | OpenAI | `gpt-image-1.5` | Default |
-| VLM | Google Gemini | `gemini-2.0-flash` | Free tier |
+| VLM | Google Gemini | `gemini-2.5-flash` | Free tier |
 | Image Generation | Google Gemini | `gemini-3-pro-image-preview` | Free tier |
 | VLM / Image | OpenRouter | Any supported model | Flexible routing |
 

configs/config.yaml

@@ -4,7 +4,7 @@
 # Provider settings
 vlm:
   provider: gemini
-  model: gemini-2.0-flash
+  model: gemini-2.5-flash
 
 image:
   provider: google_imagen

configs/provider/vlm/gemini.yaml

@@ -7,7 +7,7 @@ capabilities:
   - vision_input
   - json_mode
 config:
-  model: gemini-2.0-flash
+  model: gemini-2.5-flash
   api_key: ${GOOGLE_API_KEY}
   temperature: 1.0
   max_tokens: 4096

examples/generate_diagram.py

@@ -39,7 +39,7 @@ async def main():
 
     settings = Settings(
         vlm_provider="gemini",
-        vlm_model="gemini-2.0-flash",
+        vlm_model="gemini-2.5-flash",
         image_provider="google_imagen",
         image_model="gemini-3-pro-image-preview",
         refinement_iterations=2,

paperbanana/core/config.py

@@ -16,7 +16,7 @@ class VLMConfig(BaseSettings):
     """VLM provider configuration."""
 
     provider: str = "gemini"
-    model: str = "gemini-2.0-flash"
+    model: str = "gemini-2.5-flash"
 
 
 class ImageConfig(BaseSettings):
@@ -57,7 +57,7 @@ class Settings(BaseSettings):
 
     # Provider settings
     vlm_provider: str = Field(default="gemini", alias="VLM_PROVIDER")
-    vlm_model: str = Field(default="gemini-2.0-flash", alias="VLM_MODEL")
+    vlm_model: str = Field(default="gemini-2.5-flash", alias="VLM_MODEL")
     image_provider: str = Field(default="google_imagen", alias="IMAGE_PROVIDER")
     image_model: str = Field(default="gemini-3-pro-image-preview", alias="IMAGE_MODEL")
 

paperbanana/providers/vlm/gemini.py

@@ -20,7 +20,7 @@ class GeminiVLM(VLMProvider):
     Free tier: https://makersuite.google.com/app/apikey
     """
 
-    def __init__(self, api_key: Optional[str] = None, model: str = "gemini-2.0-flash"):
+    def __init__(self, api_key: Optional[str] = None, model: str = "gemini-2.5-flash"):
         self._api_key = api_key
         self._model = model
         self._client = None

tests/test_providers/test_registry.py

@@ -12,12 +12,12 @@ def test_create_gemini_vlm():
     """Test creating a Gemini VLM provider."""
     settings = Settings(
         vlm_provider="gemini",
-        vlm_model="gemini-2.0-flash",
+        vlm_model="gemini-2.5-flash",
         google_api_key="test-key",
     )
     vlm = ProviderRegistry.create_vlm(settings)
     assert vlm.name == "gemini"
-    assert vlm.model_name == "gemini-2.0-flash"
+    assert vlm.model_name == "gemini-2.5-flash"
 
 
 def test_create_google_imagen_gen():