feat: add view_image tool and optimize web fetch tools

Add image viewing capability for vision-enabled models with ViewImageMiddleware and view_image_tool. Limit web_fetch tool output to 4096 characters to prevent excessive content. Update model config to support vision capability flag.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/src/agents/lead_agent/agent.py

@@ -7,6 +7,7 @@ from src.agents.middlewares.clarification_middleware import ClarificationMiddlew
 from src.agents.middlewares.thread_data_middleware import ThreadDataMiddleware
 from src.agents.middlewares.title_middleware import TitleMiddleware
 from src.agents.middlewares.uploads_middleware import UploadsMiddleware
+from src.agents.middlewares.view_image_middleware import ViewImageMiddleware
 from src.agents.thread_state import ThreadState
 from src.config.summarization_config import get_summarization_config
 from src.models import create_chat_model
@@ -174,6 +175,7 @@ Being proactive with task management demonstrates thoroughness and ensures all r
 # UploadsMiddleware should be after ThreadDataMiddleware to access thread_id
 # SummarizationMiddleware should be early to reduce context before other processing
 # TodoListMiddleware should be before ClarificationMiddleware to allow todo management
+# ViewImageMiddleware should be before ClarificationMiddleware to inject image details before LLM
 # ClarificationMiddleware should be last to intercept clarification requests after model calls
 def _build_middlewares(config: RunnableConfig):
     """Build middleware chain based on runtime configuration.
@@ -197,7 +199,24 @@ def _build_middlewares(config: RunnableConfig):
     if todo_list_middleware is not None:
         middlewares.append(todo_list_middleware)
 
-    middlewares.extend([TitleMiddleware(), ClarificationMiddleware()])
+    # Add TitleMiddleware
+    middlewares.append(TitleMiddleware())
+
+    # Add ViewImageMiddleware only if the current model supports vision
+    model_name = config.get("configurable", {}).get("model_name") or config.get("configurable", {}).get("model")
+    from src.config import get_app_config
+
+    app_config = get_app_config()
+    # If no model_name specified, use the first model (default)
+    if model_name is None and app_config.models:
+        model_name = app_config.models[0].name
+
+    model_config = app_config.get_model_config(model_name) if model_name else None
+    if model_config is not None and model_config.supports_vision:
+        middlewares.append(ViewImageMiddleware())
+
+    # ClarificationMiddleware should always be last
+    middlewares.append(ClarificationMiddleware())
     return middlewares
 
 

backend/src/agents/middlewares/view_image_middleware.py

@@ -0,0 +1,221 @@
+"""Middleware for injecting image details into conversation before LLM call."""
+
+from typing import NotRequired, override
+
+from langchain.agents import AgentState
+from langchain.agents.middleware import AgentMiddleware
+from langchain_core.messages import AIMessage, HumanMessage, ToolMessage
+from langgraph.runtime import Runtime
+
+from src.agents.thread_state import ViewedImageData
+
+
+class ViewImageMiddlewareState(AgentState):
+    """Compatible with the `ThreadState` schema."""
+
+    viewed_images: NotRequired[dict[str, ViewedImageData] | None]
+
+
+class ViewImageMiddleware(AgentMiddleware[ViewImageMiddlewareState]):
+    """Injects image details as a human message before LLM calls when view_image tools have completed.
+
+    This middleware:
+    1. Runs before each LLM call
+    2. Checks if the last assistant message contains view_image tool calls
+    3. Verifies all tool calls in that message have been completed (have corresponding ToolMessages)
+    4. If conditions are met, creates a human message with all viewed image details (including base64 data)
+    5. Adds the message to state so the LLM can see and analyze the images
+
+    This enables the LLM to automatically receive and analyze images that were loaded via view_image tool,
+    without requiring explicit user prompts to describe the images.
+    """
+
+    state_schema = ViewImageMiddlewareState
+
+    def _get_last_assistant_message(self, messages: list) -> AIMessage | None:
+        """Get the last assistant message from the message list.
+
+        Args:
+            messages: List of messages
+
+        Returns:
+            Last AIMessage or None if not found
+        """
+        for msg in reversed(messages):
+            if isinstance(msg, AIMessage):
+                return msg
+        return None
+
+    def _has_view_image_tool(self, message: AIMessage) -> bool:
+        """Check if the assistant message contains view_image tool calls.
+
+        Args:
+            message: Assistant message to check
+
+        Returns:
+            True if message contains view_image tool calls
+        """
+        if not hasattr(message, "tool_calls") or not message.tool_calls:
+            return False
+
+        return any(tool_call.get("name") == "view_image" for tool_call in message.tool_calls)
+
+    def _all_tools_completed(self, messages: list, assistant_msg: AIMessage) -> bool:
+        """Check if all tool calls in the assistant message have been completed.
+
+        Args:
+            messages: List of all messages
+            assistant_msg: The assistant message containing tool calls
+
+        Returns:
+            True if all tool calls have corresponding ToolMessages
+        """
+        if not hasattr(assistant_msg, "tool_calls") or not assistant_msg.tool_calls:
+            return False
+
+        # Get all tool call IDs from the assistant message
+        tool_call_ids = {tool_call.get("id") for tool_call in assistant_msg.tool_calls if tool_call.get("id")}
+
+        # Find the index of the assistant message
+        try:
+            assistant_idx = messages.index(assistant_msg)
+        except ValueError:
+            return False
+
+        # Get all ToolMessages after the assistant message
+        completed_tool_ids = set()
+        for msg in messages[assistant_idx + 1 :]:
+            if isinstance(msg, ToolMessage) and msg.tool_call_id:
+                completed_tool_ids.add(msg.tool_call_id)
+
+        # Check if all tool calls have been completed
+        return tool_call_ids.issubset(completed_tool_ids)
+
+    def _create_image_details_message(self, state: ViewImageMiddlewareState) -> list[str | dict]:
+        """Create a formatted message with all viewed image details.
+
+        Args:
+            state: Current state containing viewed_images
+
+        Returns:
+            List of content blocks (text and images) for the HumanMessage
+        """
+        viewed_images = state.get("viewed_images", {})
+        if not viewed_images:
+            return ["No images have been viewed."]
+
+        # Build the message with image information
+        content_blocks: list[str | dict] = [{"type": "text", "text": "Here are the images you've viewed:"}]
+
+        for image_path, image_data in viewed_images.items():
+            mime_type = image_data.get("mime_type", "unknown")
+            base64_data = image_data.get("base64", "")
+
+            # Add text description
+            content_blocks.append({"type": "text", "text": f"\n- **{image_path}** ({mime_type})"})
+
+            # Add the actual image data so LLM can "see" it
+            if base64_data:
+                content_blocks.append(
+                    {
+                        "type": "image_url",
+                        "image_url": {"url": f"data:{mime_type};base64,{base64_data}"},
+                    }
+                )
+
+        return content_blocks
+
+    def _should_inject_image_message(self, state: ViewImageMiddlewareState) -> bool:
+        """Determine if we should inject an image details message.
+
+        Args:
+            state: Current state
+
+        Returns:
+            True if we should inject the message
+        """
+        messages = state.get("messages", [])
+        if not messages:
+            return False
+
+        # Get the last assistant message
+        last_assistant_msg = self._get_last_assistant_message(messages)
+        if not last_assistant_msg:
+            return False
+
+        # Check if it has view_image tool calls
+        if not self._has_view_image_tool(last_assistant_msg):
+            return False
+
+        # Check if all tools have been completed
+        if not self._all_tools_completed(messages, last_assistant_msg):
+            return False
+
+        # Check if we've already added an image details message
+        # Look for a human message after the last assistant message that contains image details
+        assistant_idx = messages.index(last_assistant_msg)
+        for msg in messages[assistant_idx + 1 :]:
+            if isinstance(msg, HumanMessage):
+                content_str = str(msg.content)
+                if "Here are the images you've viewed" in content_str or "Here are the details of the images you've viewed" in content_str:
+                    # Already added, don't add again
+                    return False
+
+        return True
+
+    def _inject_image_message(self, state: ViewImageMiddlewareState) -> dict | None:
+        """Internal helper to inject image details message.
+
+        Args:
+            state: Current state
+
+        Returns:
+            State update with additional human message, or None if no update needed
+        """
+        if not self._should_inject_image_message(state):
+            return None
+
+        # Create the image details message with text and image content
+        image_content = self._create_image_details_message(state)
+
+        # Create a new human message with mixed content (text + images)
+        human_msg = HumanMessage(content=image_content)
+
+        print("[ViewImageMiddleware] Injecting image details message with images before LLM call")
+
+        # Return state update with the new message
+        return {"messages": [human_msg]}
+
+    @override
+    def before_model(self, state: ViewImageMiddlewareState, runtime: Runtime) -> dict | None:
+        """Inject image details message before LLM call if view_image tools have completed (sync version).
+
+        This runs before each LLM call, checking if the previous turn included view_image
+        tool calls that have all completed. If so, it injects a human message with the image
+        details so the LLM can see and analyze the images.
+
+        Args:
+            state: Current state
+            runtime: Runtime context (unused but required by interface)
+
+        Returns:
+            State update with additional human message, or None if no update needed
+        """
+        return self._inject_image_message(state)
+
+    @override
+    async def abefore_model(self, state: ViewImageMiddlewareState, runtime: Runtime) -> dict | None:
+        """Inject image details message before LLM call if view_image tools have completed (async version).
+
+        This runs before each LLM call, checking if the previous turn included view_image
+        tool calls that have all completed. If so, it injects a human message with the image
+        details so the LLM can see and analyze the images.
+
+        Args:
+            state: Current state
+            runtime: Runtime context (unused but required by interface)
+
+        Returns:
+            State update with additional human message, or None if no update needed
+        """
+        return self._inject_image_message(state)

backend/src/agents/thread_state.py

@@ -1,4 +1,4 @@
-from typing import NotRequired, TypedDict
+from typing import Annotated, NotRequired, TypedDict
 
 from langchain.agents import AgentState
 
@@ -13,10 +13,43 @@ class ThreadDataState(TypedDict):
     outputs_path: NotRequired[str | None]
 
 
+class ViewedImageData(TypedDict):
+    base64: str
+    mime_type: str
+
+
+def merge_artifacts(existing: list[str] | None, new: list[str] | None) -> list[str]:
+    """Reducer for artifacts list - merges and deduplicates artifacts."""
+    if existing is None:
+        return new or []
+    if new is None:
+        return existing
+    # Use dict.fromkeys to deduplicate while preserving order
+    return list(dict.fromkeys(existing + new))
+
+
+def merge_viewed_images(existing: dict[str, ViewedImageData] | None, new: dict[str, ViewedImageData] | None) -> dict[str, ViewedImageData]:
+    """Reducer for viewed_images dict - merges image dictionaries.
+
+    Special case: If new is an empty dict {}, it clears the existing images.
+    This allows middlewares to clear the viewed_images state after processing.
+    """
+    if existing is None:
+        return new or {}
+    if new is None:
+        return existing
+    # Special case: empty dict means clear all viewed images
+    if len(new) == 0:
+        return {}
+    # Merge dictionaries, new values override existing ones for same keys
+    return {**existing, **new}
+
+
 class ThreadState(AgentState):
     sandbox: NotRequired[SandboxState | None]
     thread_data: NotRequired[ThreadDataState | None]
     title: NotRequired[str | None]
-    artifacts: NotRequired[list[str] | None]
+    artifacts: Annotated[list[str], merge_artifacts]
     todos: NotRequired[list | None]
     uploaded_files: NotRequired[list[dict] | None]
+    viewed_images: Annotated[dict[str, ViewedImageData], merge_viewed_images]  # image_path -> {base64, mime_type}

backend/src/community/firecrawl/tools.py

@@ -70,4 +70,4 @@ def web_fetch_tool(url: str) -> str:
     except Exception as e:
         return f"Error: {str(e)}"
 
-    return f"# {title}\n\n{markdown_content}"
+    return f"# {title}\n\n{markdown_content[:4096]}"

backend/src/community/jina_ai/tools.py

@@ -25,4 +25,4 @@ def web_fetch_tool(url: str) -> str:
         timeout = config.model_extra.get("timeout")
     html_content = jina_client.crawl(url, return_format="html", timeout=timeout)
     article = readability_extractor.extract_article(html_content)
-    return article.to_markdown()
+    return article.to_markdown()[:4096]

backend/src/community/tavily/tools.py

@@ -57,6 +57,6 @@ def web_fetch_tool(url: str) -> str:
         return f"Error: {res['failed_results'][0]['error']}"
     elif "results" in res and len(res["results"]) > 0:
         result = res["results"][0]
-        return f"# {result['title']}\n\n{result['raw_content']}"
+        return f"# {result['title']}\n\n{result['raw_content'][:4096]}"
     else:
         return "Error: No results found"

backend/src/config/model_config.py

@@ -18,3 +18,4 @@ class ModelConfig(BaseModel):
         default_factory=lambda: None,
         description="Extra settings to be passed to the model when thinking is enabled",
     )
+    supports_vision: bool = Field(default_factory=lambda: False, description="Whether the model supports vision/image inputs")

backend/src/models/factory.py

@@ -29,6 +29,7 @@ def create_chat_model(name: str | None = None, thinking_enabled: bool = False, *
             "description",
             "supports_thinking",
             "when_thinking_enabled",
+            "supports_vision",
         },
     )
     if thinking_enabled and model_config.when_thinking_enabled is not None:

backend/src/tools/builtins/__init__.py

@@ -1,4 +1,5 @@
 from .clarification_tool import ask_clarification_tool
 from .present_file_tool import present_file_tool
+from .view_image_tool import view_image_tool
 
-__all__ = ["present_file_tool", "ask_clarification_tool"]
+__all__ = ["present_file_tool", "ask_clarification_tool", "view_image_tool"]

backend/src/tools/builtins/present_file_tool.py

@@ -28,15 +28,12 @@ def present_file_tool(
 
     Notes:
     - You should call this tool after creating files and moving them to the `/mnt/user-data/outputs` directory.
-    - IMPORTANT: Do NOT call this tool in parallel with other tools. Call it separately.
+    - This tool can be safely called in parallel with other tools. State updates are handled by a reducer to prevent conflicts.
 
     Args:
         filepaths: List of absolute file paths to present to the user. **Only** files in `/mnt/user-data/outputs` can be presented.
     """
-    existing_artifacts = runtime.state.get("artifacts") or []
+    # The merge_artifacts reducer will handle merging and deduplication
-    # Use dict.fromkeys to deduplicate while preserving order
-    new_artifacts = list(dict.fromkeys(existing_artifacts + filepaths))
-    runtime.state["artifacts"] = new_artifacts
     return Command(
-        update={"artifacts": new_artifacts, "messages": [ToolMessage("Successfully presented files", tool_call_id=tool_call_id)]},
+        update={"artifacts": filepaths, "messages": [ToolMessage("Successfully presented files", tool_call_id=tool_call_id)]},
     )

backend/src/tools/builtins/view_image_tool.py

@@ -0,0 +1,94 @@
+import base64
+import mimetypes
+from pathlib import Path
+from typing import Annotated
+
+from langchain.tools import InjectedToolCallId, ToolRuntime, tool
+from langchain_core.messages import ToolMessage
+from langgraph.types import Command
+from langgraph.typing import ContextT
+
+from src.agents.thread_state import ThreadState
+from src.sandbox.tools import get_thread_data, replace_virtual_path
+
+
+@tool("view_image", parse_docstring=True)
+def view_image_tool(
+    runtime: ToolRuntime[ContextT, ThreadState],
+    image_path: str,
+    tool_call_id: Annotated[str, InjectedToolCallId],
+) -> Command:
+    """Read an image file.
+
+    Use this tool to read an image file and make it available for display.
+
+    When to use the view_image tool:
+    - When you need to view an image file.
+
+    When NOT to use the view_image tool:
+    - For non-image files (use present_files instead)
+    - For multiple files at once (use present_files instead)
+
+    Args:
+        image_path: Absolute path to the image file. Common formats supported: jpg, jpeg, png, webp.
+    """
+    # Replace virtual path with actual path
+    # /mnt/user-data/* paths are mapped to thread-specific directories
+    thread_data = get_thread_data(runtime)
+    actual_path = replace_virtual_path(image_path, thread_data)
+
+    # Validate that the path is absolute
+    path = Path(actual_path)
+    if not path.is_absolute():
+        return Command(
+            update={"messages": [ToolMessage(f"Error: Path must be absolute, got: {image_path}", tool_call_id=tool_call_id)]},
+        )
+
+    # Validate that the file exists
+    if not path.exists():
+        return Command(
+            update={"messages": [ToolMessage(f"Error: Image file not found: {image_path}", tool_call_id=tool_call_id)]},
+        )
+
+    # Validate that it's a file (not a directory)
+    if not path.is_file():
+        return Command(
+            update={"messages": [ToolMessage(f"Error: Path is not a file: {image_path}", tool_call_id=tool_call_id)]},
+        )
+
+    # Validate image extension
+    valid_extensions = {".jpg", ".jpeg", ".png", ".webp"}
+    if path.suffix.lower() not in valid_extensions:
+        return Command(
+            update={"messages": [ToolMessage(f"Error: Unsupported image format: {path.suffix}. Supported formats: {', '.join(valid_extensions)}", tool_call_id=tool_call_id)]},
+        )
+
+    # Detect MIME type from file extension
+    mime_type, _ = mimetypes.guess_type(actual_path)
+    if mime_type is None:
+        # Fallback to default MIME types for common image formats
+        extension_to_mime = {
+            ".jpg": "image/jpeg",
+            ".jpeg": "image/jpeg",
+            ".png": "image/png",
+            ".webp": "image/webp",
+        }
+        mime_type = extension_to_mime.get(path.suffix.lower(), "application/octet-stream")
+
+    # Read image file and convert to base64
+    try:
+        with open(actual_path, "rb") as f:
+            image_data = f.read()
+            image_base64 = base64.b64encode(image_data).decode("utf-8")
+    except Exception as e:
+        return Command(
+            update={"messages": [ToolMessage(f"Error reading image file: {str(e)}", tool_call_id=tool_call_id)]},
+        )
+
+    # Update viewed_images in state
+    # The merge_viewed_images reducer will handle merging with existing images
+    new_viewed_images = {image_path: {"base64": image_base64, "mime_type": mime_type}}
+
+    return Command(
+        update={"viewed_images": new_viewed_images, "messages": [ToolMessage("Successfully read image", tool_call_id=tool_call_id)]},
+    )

config.example.yaml

@@ -21,6 +21,7 @@ models:
     api_key: $OPENAI_API_KEY  # Use environment variable
     max_tokens: 4096
     temperature: 0.7
+    supports_vision: true  # Enable vision support for view_image tool
 
   # Example: Anthropic Claude model
   # - name: claude-3-5-sonnet
@@ -29,6 +30,7 @@ models:
   #   model: claude-3-5-sonnet-20241022
   #   api_key: $ANTHROPIC_API_KEY
   #   max_tokens: 8192
+  #   supports_vision: true  # Enable vision support for view_image tool
 
   # Example: DeepSeek model (with thinking support)
   # - name: deepseek-v3
@@ -38,6 +40,7 @@ models:
   #   api_key: $DEEPSEEK_API_KEY
   #   max_tokens: 16384
   #   supports_thinking: true
+  #   supports_vision: false  # DeepSeek V3 does not support vision
   #   when_thinking_enabled:
   #     extra_body:
   #       thinking:
@@ -51,6 +54,7 @@ models:
   #   api_base: https://ark.cn-beijing.volces.com/api/v3
   #   api_key: $VOLCENGINE_API_KEY
   #   supports_thinking: true
+  #   supports_vision: false  # Check your specific model's capabilities
   #   when_thinking_enabled:
   #     extra_body:
   #       thinking:
@@ -65,6 +69,7 @@ models:
   #   api_key: $MOONSHOT_API_KEY
   #   max_tokens: 32768
   #   supports_thinking: true
+  #   supports_vision: false  # Check your specific model's capabilities
   #   when_thinking_enabled:
   #     extra_body:
   #       thinking:
@@ -107,6 +112,11 @@ tools:
     use: src.community.image_search.tools:image_search_tool
     max_results: 5
 
+  # View image tool (display local images to user)
+  - name: view_image
+    group: file:read
+    use: src.tools.builtins:view_image_tool
+
   # File operations tools
   - name: ls
     group: file:read