feat: add reasoning_effort configuration support for Doubao/GPT-5 models (#947)

* feat: Add reasoning effort configuration support

* Add `reasoning_effort` parameter to model config and agent initialization
* Support reasoning effort levels (minimal/low/medium/high) for Doubao/GPT-5 models
* Add UI controls in input box for reasoning effort selection
* Update doubao-seed-1.8 example config with reasoning effort support

Fixes & Cleanup:
* Ensure UTF-8 encoding for file operations
* Remove unused imports

* fix: set reasoning_effort to None for unsupported models

* fix: unit test error

* Update frontend/src/components/workspace/input-box.tsx

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/src/agents/lead_agent/agent.py

@@ -256,6 +256,7 @@ def make_lead_agent(config: RunnableConfig):
     from src.tools import get_available_tools
 
     thinking_enabled = config.get("configurable", {}).get("thinking_enabled", True)
+    reasoning_effort = config.get("configurable", {}).get("reasoning_effort", None)
     requested_model_name = config.get("configurable", {}).get("model_name") or config.get("configurable", {}).get("model")
     model_name = _resolve_model_name(requested_model_name)
     if model_name is None:
@@ -274,8 +275,9 @@ def make_lead_agent(config: RunnableConfig):
         thinking_enabled = False
 
     logger.info(
-        "thinking_enabled: %s, model_name: %s, is_plan_mode: %s, subagent_enabled: %s, max_concurrent_subagents: %s",
+        "thinking_enabled: %s, reasoning_effort: %s, model_name: %s, is_plan_mode: %s, subagent_enabled: %s, max_concurrent_subagents: %s",
         thinking_enabled,
+        reasoning_effort,
         model_name,
         is_plan_mode,
         subagent_enabled,
@@ -289,13 +291,14 @@ def make_lead_agent(config: RunnableConfig):
         {
             "model_name": model_name or "default",
             "thinking_enabled": thinking_enabled,
+            "reasoning_effort": reasoning_effort,
             "is_plan_mode": is_plan_mode,
             "subagent_enabled": subagent_enabled,
         }
     )
 
     return create_agent(
-        model=create_chat_model(name=model_name, thinking_enabled=thinking_enabled),
+        model=create_chat_model(name=model_name, thinking_enabled=thinking_enabled, reasoning_effort=reasoning_effort),
         tools=get_available_tools(model_name=model_name, subagent_enabled=subagent_enabled),
         middleware=_build_middlewares(config, model_name=model_name),
         system_prompt=apply_prompt_template(subagent_enabled=subagent_enabled, max_concurrent_subagents=max_concurrent_subagents),

backend/src/client.py

@@ -400,6 +400,7 @@ class DeerFlowClient:
                     "display_name": getattr(model, "display_name", None),
                     "description": getattr(model, "description", None),
                     "supports_thinking": getattr(model, "supports_thinking", False),
+                    "supports_reasoning_effort": getattr(model, "supports_reasoning_effort", False),
                 }
                 for model in self._app_config.models
             ]
@@ -458,6 +459,7 @@ class DeerFlowClient:
             "display_name": getattr(model, "display_name", None),
             "description": getattr(model, "description", None),
             "supports_thinking": getattr(model, "supports_thinking", False),
+            "supports_reasoning_effort": getattr(model, "supports_reasoning_effort", False),
         }
 
     # ------------------------------------------------------------------

backend/src/config/app_config.py

@@ -72,7 +72,7 @@ class AppConfig(BaseModel):
             AppConfig: The loaded config.
         """
         resolved_path = cls.resolve_config_path(config_path)
-        with open(resolved_path) as f:
+        with open(resolved_path, encoding="utf-8") as f:
             config_data = yaml.safe_load(f)
         config_data = cls.resolve_env_variables(config_data)
 

backend/src/config/extensions_config.py

@@ -133,7 +133,7 @@ class ExtensionsConfig(BaseModel):
             # Return empty config if extensions config file is not found
             return cls(mcp_servers={}, skills={})
 
-        with open(resolved_path) as f:
+        with open(resolved_path, encoding="utf-8") as f:
             config_data = json.load(f)
 
         cls.resolve_env_variables(config_data)

backend/src/config/model_config.py

@@ -14,6 +14,7 @@ class ModelConfig(BaseModel):
     model: str = Field(..., description="Model name")
     model_config = ConfigDict(extra="allow")
     supports_thinking: bool = Field(default_factory=lambda: False, description="Whether the model supports thinking")
+    supports_reasoning_effort: bool = Field(default_factory=lambda: False, description="Whether the model supports reasoning effort")
     when_thinking_enabled: dict | None = Field(
         default_factory=lambda: None,
         description="Extra settings to be passed to the model when thinking is enabled",

backend/src/gateway/routers/models.py

@@ -13,6 +13,7 @@ class ModelResponse(BaseModel):
     display_name: str | None = Field(None, description="Human-readable name")
     description: str | None = Field(None, description="Model description")
     supports_thinking: bool = Field(default=False, description="Whether model supports thinking mode")
+    supports_reasoning_effort: bool = Field(default=False, description="Whether model supports reasoning effort")
 
 
 class ModelsListResponse(BaseModel):
@@ -63,6 +64,7 @@ async def list_models() -> ModelsListResponse:
             display_name=model.display_name,
             description=model.description,
             supports_thinking=model.supports_thinking,
+            supports_reasoning_effort=model.supports_reasoning_effort,
         )
         for model in config.models
     ]
@@ -107,4 +109,5 @@ async def get_model(model_name: str) -> ModelResponse:
         display_name=model.display_name,
         description=model.description,
         supports_thinking=model.supports_thinking,
+        supports_reasoning_effort=model.supports_reasoning_effort,
     )

backend/src/models/factory.py

@@ -32,6 +32,7 @@ def create_chat_model(name: str | None = None, thinking_enabled: bool = False, *
             "display_name",
             "description",
             "supports_thinking",
+            "supports_reasoning_effort",
             "when_thinking_enabled",
             "supports_vision",
         },
@@ -40,6 +41,11 @@ def create_chat_model(name: str | None = None, thinking_enabled: bool = False, *
         if not model_config.supports_thinking:
             raise ValueError(f"Model {name} does not support thinking. Set `supports_thinking` to true in the `config.yaml` to enable thinking.") from None
         model_settings_from_config.update(model_config.when_thinking_enabled)
+    if not thinking_enabled and model_config.when_thinking_enabled and model_config.when_thinking_enabled.get("extra_body", {}).get("thinking", {}).get("type"):
+        kwargs.update({"extra_body": {"thinking": {"type": "disabled"}}})
+        kwargs.update({"reasoning_effort": "minimal"})
+    if not model_config.supports_reasoning_effort:
+        kwargs.update({"reasoning_effort": None})
     model_instance = model_class(**kwargs, **model_settings_from_config)
 
     if is_tracing_enabled():

backend/src/reflection/resolvers.py

@@ -1,7 +1,4 @@
 from importlib import import_module
-from typing import TypeVar
-
-T = TypeVar("T")
 
 
 def resolve_variable[T](