feat: add AIO sandbox provider and auto title generation (#1)

- Add AioSandboxProvider for Docker-based sandbox execution with
  configurable container lifecycle, volume mounts, and port management
- Add TitleMiddleware to auto-generate thread titles after first
  user-assistant exchange using LLM
- Add Claude Code documentation (CLAUDE.md, AGENTS.md)
- Extend SandboxConfig with Docker-specific options (image, port, mounts)
- Fix hardcoded mount path to use expanduser
- Add agent-sandbox and dotenv dependencies

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/config/app_config.py

@@ -3,12 +3,16 @@ from pathlib import Path
 from typing import Self
 
 import yaml
+from dotenv import load_dotenv
 from pydantic import BaseModel, ConfigDict, Field
 
 from src.config.model_config import ModelConfig
 from src.config.sandbox_config import SandboxConfig
+from src.config.title_config import load_title_config_from_dict
 from src.config.tool_config import ToolConfig, ToolGroupConfig
 
+load_dotenv()
+
 
 class AppConfig(BaseModel):
     """Config for the DeerFlow application"""
@@ -64,6 +68,11 @@ class AppConfig(BaseModel):
         with open(resolved_path) as f:
             config_data = yaml.safe_load(f)
         cls.resolve_env_variables(config_data)
+
+        # Load title config if present
+        if "title" in config_data:
+            load_title_config_from_dict(config_data["title"])
+
         result = cls.model_validate(config_data)
         return result
 

backend/src/config/sandbox_config.py

@@ -1,10 +1,56 @@
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, ConfigDict, Field
+
+
+class VolumeMountConfig(BaseModel):
+    """Configuration for a volume mount."""
+
+    host_path: str = Field(..., description="Path on the host machine")
+    container_path: str = Field(..., description="Path inside the container")
+    read_only: bool = Field(default=False, description="Whether the mount is read-only")
 
 
 class SandboxConfig(BaseModel):
-    """Config section for a sandbox"""
+    """Config section for a sandbox.
+
+    Common options:
+        use: Class path of the sandbox provider (required)
+
+    AioSandboxProvider specific options:
+        image: Docker image to use (default: enterprise-public-cn-beijing.cr.volces.com/vefaas-public/all-in-one-sandbox:latest)
+        port: Base port for sandbox containers (default: 8080)
+        base_url: If set, uses existing sandbox instead of starting new container
+        auto_start: Whether to automatically start Docker container (default: true)
+        container_prefix: Prefix for container names (default: deer-flow-sandbox)
+        mounts: List of volume mounts to share directories with the container
+    """
 
     use: str = Field(
         ...,
-        description="Class path of the sandbox provider(e.g. src.sandbox.local:LocalSandbox)",
+        description="Class path of the sandbox provider (e.g. src.sandbox.local:LocalSandboxProvider)",
     )
+    image: str | None = Field(
+        default=None,
+        description="Docker image to use for the sandbox container",
+    )
+    port: int | None = Field(
+        default=None,
+        description="Base port for sandbox containers",
+    )
+    base_url: str | None = Field(
+        default=None,
+        description="If set, uses existing sandbox at this URL instead of starting new container",
+    )
+    auto_start: bool | None = Field(
+        default=None,
+        description="Whether to automatically start Docker container",
+    )
+    container_prefix: str | None = Field(
+        default=None,
+        description="Prefix for container names",
+    )
+    mounts: list[VolumeMountConfig] = Field(
+        default_factory=list,
+        description="List of volume mounts to share directories between host and container",
+    )
+
+    model_config = ConfigDict(extra="allow")

backend/src/config/title_config.py

@@ -0,0 +1,53 @@
+"""Configuration for automatic thread title generation."""
+
+from pydantic import BaseModel, Field
+
+
+class TitleConfig(BaseModel):
+    """Configuration for automatic thread title generation."""
+
+    enabled: bool = Field(
+        default=True,
+        description="Whether to enable automatic title generation",
+    )
+    max_words: int = Field(
+        default=6,
+        ge=1,
+        le=20,
+        description="Maximum number of words in the generated title",
+    )
+    max_chars: int = Field(
+        default=60,
+        ge=10,
+        le=200,
+        description="Maximum number of characters in the generated title",
+    )
+    model_name: str | None = Field(
+        default=None,
+        description="Model name to use for title generation (None = use default model)",
+    )
+    prompt_template: str = Field(
+        default=("Generate a concise title (max {max_words} words) for this conversation.\nUser: {user_msg}\nAssistant: {assistant_msg}\n\nReturn ONLY the title, no quotes, no explanation."),
+        description="Prompt template for title generation",
+    )
+
+
+# Global configuration instance
+_title_config: TitleConfig = TitleConfig()
+
+
+def get_title_config() -> TitleConfig:
+    """Get the current title configuration."""
+    return _title_config
+
+
+def set_title_config(config: TitleConfig) -> None:
+    """Set the title configuration."""
+    global _title_config
+    _title_config = config
+
+
+def load_title_config_from_dict(config_dict: dict) -> None:
+    """Load title configuration from a dictionary."""
+    global _title_config
+    _title_config = TitleConfig(**config_dict)