From 3191e819397a56a4827692535fd6ac8cd7a7ffba Mon Sep 17 00:00:00 2001
From: Willem Jiang <willem.jiang@gmail.com>
Date: Sat, 6 Dec 2025 11:15:11 +0800
Subject: [PATCH] fix: passing the locale to create_react_agent (#745)

---
 src/agents/agents.py | 11 ++++++++---
 src/graph/nodes.py   |  6 ++++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/agents/agents.py b/src/agents/agents.py
index df94bd3..7310cc1 100644
--- a/src/agents/agents.py
+++ b/src/agents/agents.py
@@ -22,6 +22,7 @@ def create_agent(
     prompt_template: str,
     pre_model_hook: callable = None,
     interrupt_before_tools: Optional[List[str]] = None,
+    locale: str = "en-US",
 ):
     """Factory function to create agents with consistent configuration.
 
@@ -32,6 +33,7 @@ def create_agent(
         prompt_template: Name of the prompt template to use
         pre_model_hook: Optional hook to preprocess state before model invocation
         interrupt_before_tools: Optional list of tool names to interrupt before execution
+        locale: Language locale for prompt template selection (e.g., en-US, zh-CN)
 
     Returns:
         A configured agent graph
@@ -62,13 +64,16 @@ def create_agent(
     llm_type = AGENT_LLM_MAP.get(agent_type, "basic")
     logger.debug(f"Agent '{agent_name}' using LLM type: {llm_type}")
     
-    logger.debug(f"Creating ReAct agent '{agent_name}'")
+    logger.debug(f"Creating ReAct agent '{agent_name}' with locale: {locale}")
+    # Use closure to capture locale from the workflow state instead of relying on
+    # agent state.get("locale"), which doesn't have the locale field
+    # See: https://github.com/bytedance/deer-flow/issues/743
     agent = create_react_agent(
         name=agent_name,
         model=get_llm_by_type(llm_type),
         tools=processed_tools,
-        prompt=lambda state: apply_prompt_template(
-            prompt_template, state, locale=state.get("locale", "en-US")
+        prompt=lambda state, captured_locale=locale: apply_prompt_template(
+            prompt_template, state, locale=captured_locale
         ),
         pre_model_hook=pre_model_hook,
     )
diff --git a/src/graph/nodes.py b/src/graph/nodes.py
index ed7584d..8f9497e 100644
--- a/src/graph/nodes.py
+++ b/src/graph/nodes.py
@@ -1115,6 +1115,10 @@ async def _setup_and_execute_agent_step(
     configurable = Configuration.from_runnable_config(config)
     mcp_servers = {}
     enabled_tools = {}
+    
+    # Get locale from workflow state to pass to agent creation
+    # This fixes issue #743 where locale was not correctly retrieved in agent prompt
+    locale = state.get("locale", "en-US")
 
     # Extract MCP server configuration for this agent type
     if configurable.mcp_settings:
@@ -1152,6 +1156,7 @@ async def _setup_and_execute_agent_step(
             agent_type,
             pre_model_hook,
             interrupt_before_tools=configurable.interrupt_before_tools,
+            locale=locale,
         )
         return await _execute_agent_step(state, agent, agent_type, config)
     else:
@@ -1165,6 +1170,7 @@ async def _setup_and_execute_agent_step(
             agent_type,
             pre_model_hook,
             interrupt_before_tools=configurable.interrupt_before_tools,
+            locale=locale,
         )
         return await _execute_agent_step(state, agent, agent_type, config)