refactor(config): eliminate global mutable state, wire DeerFlowContext into runtime

- Freeze all config models (AppConfig + 15 sub-configs) with frozen=True
- Purify from_file() — remove 9 load_*_from_dict() side-effect calls
- Replace mtime/reload/push/pop machinery with single ContextVar + init_app_config()
- Delete 10 sub-module globals and their getters/setters/loaders
- Migrate 50+ consumers from get_*_config() to get_app_config().xxx

- Expand DeerFlowContext: app_config + thread_id + agent_name (frozen dataclass)
- Wire into Gateway runtime (worker.py) and DeerFlowClient via context= parameter
- Remove sandbox_id from runtime.context — flows through ThreadState.sandbox only
- Middleware/tools access runtime.context directly via Runtime[DeerFlowContext] generic
- resolve_context() retained at server entry points for LangGraph Server fallback

backend/app/channels/service.py

@@ -67,9 +67,9 @@ class ChannelService:
     @classmethod
     def from_app_config(cls) -> ChannelService:
         """Create a ChannelService from the application config."""
-        from deerflow.config.app_config import get_app_config
+        from deerflow.config.app_config import AppConfig
 
-        config = get_app_config()
+        config = AppConfig.current()
         channels_config = {}
         # extra fields are allowed by AppConfig (extra="allow")
         extra = config.model_extra or {}

backend/app/gateway/app.py

@@ -21,7 +21,7 @@ from app.gateway.routers import (
     threads,
     uploads,
 )
-from deerflow.config.app_config import get_app_config
+from deerflow.config.app_config import AppConfig
 
 # Configure logging
 logging.basicConfig(
@@ -39,7 +39,7 @@ async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
 
     # Load config and check necessary environment variables at startup
     try:
-        get_app_config()
+        AppConfig.current()
         logger.info("Configuration loaded successfully")
     except Exception as e:
         error_msg = f"Failed to load configuration during gateway startup: {e}"

backend/app/gateway/routers/mcp.py

@@ -6,7 +6,8 @@ from typing import Literal
 from fastapi import APIRouter, HTTPException
 from pydantic import BaseModel, Field
 
-from deerflow.config.extensions_config import ExtensionsConfig, get_extensions_config, reload_extensions_config
+from deerflow.config.app_config import AppConfig
+from deerflow.config.extensions_config import ExtensionsConfig
 
 logger = logging.getLogger(__name__)
 router = APIRouter(prefix="/api", tags=["mcp"])
@@ -90,9 +91,9 @@ async def get_mcp_configuration() -> McpConfigResponse:
         }
         ```
     """
-    config = get_extensions_config()
+    ext = AppConfig.current().extensions
 
-    return McpConfigResponse(mcp_servers={name: McpServerConfigResponse(**server.model_dump()) for name, server in config.mcp_servers.items()})
+    return McpConfigResponse(mcp_servers={name: McpServerConfigResponse(**server.model_dump()) for name, server in ext.mcp_servers.items()})
 
 
 @router.put(
@@ -143,12 +144,12 @@ async def update_mcp_configuration(request: McpConfigUpdateRequest) -> McpConfig
             logger.info(f"No existing extensions config found. Creating new config at: {config_path}")
 
         # Load current config to preserve skills configuration
-        current_config = get_extensions_config()
+        current_ext = AppConfig.current().extensions
 
         # Convert request to dict format for JSON serialization
         config_data = {
             "mcpServers": {name: server.model_dump() for name, server in request.mcp_servers.items()},
-            "skills": {name: {"enabled": skill.enabled} for name, skill in current_config.skills.items()},
+            "skills": {name: {"enabled": skill.enabled} for name, skill in current_ext.skills.items()},
         }
 
         # Write the configuration to file
@@ -161,8 +162,9 @@ async def update_mcp_configuration(request: McpConfigUpdateRequest) -> McpConfig
         # will detect config file changes via mtime and reinitialize MCP tools automatically
 
         # Reload the configuration and update the global cache
-        reloaded_config = reload_extensions_config()
-        return McpConfigResponse(mcp_servers={name: McpServerConfigResponse(**server.model_dump()) for name, server in reloaded_config.mcp_servers.items()})
+        AppConfig.init(AppConfig.from_file())
+        reloaded_ext = AppConfig.current().extensions
+        return McpConfigResponse(mcp_servers={name: McpServerConfigResponse(**server.model_dump()) for name, server in reloaded_ext.mcp_servers.items()})
 
     except Exception as e:
         logger.error(f"Failed to update MCP configuration: {e}", exc_info=True)

backend/app/gateway/routers/memory.py

@@ -12,7 +12,7 @@ from deerflow.agents.memory.updater import (
     reload_memory_data,
     update_memory_fact,
 )
-from deerflow.config.memory_config import get_memory_config
+from deerflow.config.app_config import AppConfig
 
 router = APIRouter(prefix="/api", tags=["memory"])
 
@@ -311,7 +311,7 @@ async def get_memory_config_endpoint() -> MemoryConfigResponse:
         }
         ```
     """
-    config = get_memory_config()
+    config = AppConfig.current().memory
     return MemoryConfigResponse(
         enabled=config.enabled,
         storage_path=config.storage_path,
@@ -336,7 +336,7 @@ async def get_memory_status() -> MemoryStatusResponse:
     Returns:
         Combined memory configuration and current data.
     """
-    config = get_memory_config()
+    config = AppConfig.current().memory
     memory_data = get_memory_data()
 
     return MemoryStatusResponse(

backend/app/gateway/routers/models.py

@@ -1,7 +1,7 @@
 from fastapi import APIRouter, HTTPException
 from pydantic import BaseModel, Field
 
-from deerflow.config import get_app_config
+from deerflow.config.app_config import AppConfig
 
 router = APIRouter(prefix="/api", tags=["models"])
 
@@ -58,7 +58,7 @@ async def list_models() -> ModelsListResponse:
         }
         ```
     """
-    config = get_app_config()
+    config = AppConfig.current()
     models = [
         ModelResponse(
             name=model.name,
@@ -101,7 +101,7 @@ async def get_model(model_name: str) -> ModelResponse:
         }
         ```
     """
-    config = get_app_config()
+    config = AppConfig.current()
     model = config.get_model_config(model_name)
     if model is None:
         raise HTTPException(status_code=404, detail=f"Model '{model_name}' not found")

backend/app/gateway/routers/skills.py

@@ -8,7 +8,8 @@ from pydantic import BaseModel, Field
 
 from app.gateway.path_utils import resolve_thread_virtual_path
 from deerflow.agents.lead_agent.prompt import refresh_skills_system_prompt_cache_async
-from deerflow.config.extensions_config import ExtensionsConfig, SkillStateConfig, get_extensions_config, reload_extensions_config
+from deerflow.config.app_config import AppConfig
+from deerflow.config.extensions_config import ExtensionsConfig, SkillStateConfig
 from deerflow.skills import Skill, load_skills
 from deerflow.skills.installer import SkillAlreadyExistsError, install_skill_from_archive
 from deerflow.skills.manager import (
@@ -325,19 +326,19 @@ async def update_skill(skill_name: str, request: SkillUpdateRequest) -> SkillRes
             config_path = Path.cwd().parent / "extensions_config.json"
             logger.info(f"No existing extensions config found. Creating new config at: {config_path}")
 
-        extensions_config = get_extensions_config()
-        extensions_config.skills[skill_name] = SkillStateConfig(enabled=request.enabled)
+        ext = AppConfig.current().extensions
+        ext.skills[skill_name] = SkillStateConfig(enabled=request.enabled)
 
         config_data = {
-            "mcpServers": {name: server.model_dump() for name, server in extensions_config.mcp_servers.items()},
-            "skills": {name: {"enabled": skill_config.enabled} for name, skill_config in extensions_config.skills.items()},
+            "mcpServers": {name: server.model_dump() for name, server in ext.mcp_servers.items()},
+            "skills": {name: {"enabled": skill_config.enabled} for name, skill_config in ext.skills.items()},
         }
 
         with open(config_path, "w", encoding="utf-8") as f:
             json.dump(config_data, f, indent=2)
 
         logger.info(f"Skills configuration updated and saved to: {config_path}")
-        reload_extensions_config()
+        AppConfig.init(AppConfig.from_file())
         await refresh_skills_system_prompt_cache_async()
 
         skills = load_skills(enabled_only=False)