diff --git a/svc/llm/transports/openai_chat_completions.py b/svc/llm/transports/openai_chat_completions.py
index 5733bfbe..593e5baa 100644
--- a/svc/llm/transports/openai_chat_completions.py
+++ b/svc/llm/transports/openai_chat_completions.py
@@ -115,17 +115,11 @@ def _openai_tool_function_strict_enabled() -> bool:
     Default **on** for every provider/model: many gateways ignore unknown ``function`` keys; some
     reject them—use ``AIA_TOOL_FUNCTION_STRICT=0`` to disable.
 
-    ``AIA_DEEPSEEK_STRICT_TOOL_MODE=0`` is still honored as a legacy global opt-out when
-    ``AIA_TOOL_FUNCTION_STRICT`` is unset. DeepSeek strict mode details:
+    DeepSeek documents ``function.strict`` in strict (Beta) tool mode:
     https://api-docs.deepseek.com/zh-cn/guides/tool_calls
     """
-    primary = str(os.getenv("AIA_TOOL_FUNCTION_STRICT") or "").strip().lower()
-    if primary in ("0", "false", "no", "off"):
-        return False
-    if primary in ("1", "true", "yes", "on"):
-        return True
-    legacy = str(os.getenv("AIA_DEEPSEEK_STRICT_TOOL_MODE") or "").strip().lower()
-    if legacy in ("0", "false", "no", "off"):
+    raw = str(os.getenv("AIA_TOOL_FUNCTION_STRICT") or "").strip().lower()
+    if raw in ("0", "false", "no", "off"):
         return False
     return True
 
diff --git a/tests/test_openai_chat_strict_tool_mode.py b/tests/test_openai_chat_strict_tool_mode.py
index 875d2d0b..7ead7499 100644
--- a/tests/test_openai_chat_strict_tool_mode.py
+++ b/tests/test_openai_chat_strict_tool_mode.py
@@ -13,15 +13,12 @@ from svc.llm.transports.openai_chat_completions import (
 
 class OpenAIToolFunctionStrictTests(unittest.TestCase):
     def test_enabled_by_default(self) -> None:
-        prev_t = os.environ.pop("AIA_TOOL_FUNCTION_STRICT", None)
-        prev_d = os.environ.pop("AIA_DEEPSEEK_STRICT_TOOL_MODE", None)
+        prev = os.environ.pop("AIA_TOOL_FUNCTION_STRICT", None)
         try:
             self.assertTrue(_openai_tool_function_strict_enabled())
         finally:
-            if prev_t is not None:
-                os.environ["AIA_TOOL_FUNCTION_STRICT"] = prev_t
-            if prev_d is not None:
-                os.environ["AIA_DEEPSEEK_STRICT_TOOL_MODE"] = prev_d
+            if prev is not None:
+                os.environ["AIA_TOOL_FUNCTION_STRICT"] = prev
 
     def test_disabled_when_tool_function_strict_off(self) -> None:
         prev = os.environ.get("AIA_TOOL_FUNCTION_STRICT")
@@ -34,37 +31,6 @@ class OpenAIToolFunctionStrictTests(unittest.TestCase):
             else:
                 os.environ["AIA_TOOL_FUNCTION_STRICT"] = prev
 
-    def test_disabled_legacy_deepseek_env_when_primary_unset(self) -> None:
-        prev_t = os.environ.pop("AIA_TOOL_FUNCTION_STRICT", None)
-        prev_d = os.environ.get("AIA_DEEPSEEK_STRICT_TOOL_MODE")
-        try:
-            os.environ["AIA_DEEPSEEK_STRICT_TOOL_MODE"] = "0"
-            self.assertFalse(_openai_tool_function_strict_enabled())
-        finally:
-            if prev_t is not None:
-                os.environ["AIA_TOOL_FUNCTION_STRICT"] = prev_t
-            if prev_d is None:
-                os.environ.pop("AIA_DEEPSEEK_STRICT_TOOL_MODE", None)
-            else:
-                os.environ["AIA_DEEPSEEK_STRICT_TOOL_MODE"] = prev_d
-
-    def test_primary_env_overrides_legacy_off(self) -> None:
-        prev_t = os.environ.get("AIA_TOOL_FUNCTION_STRICT")
-        prev_d = os.environ.get("AIA_DEEPSEEK_STRICT_TOOL_MODE")
-        try:
-            os.environ["AIA_DEEPSEEK_STRICT_TOOL_MODE"] = "0"
-            os.environ["AIA_TOOL_FUNCTION_STRICT"] = "1"
-            self.assertTrue(_openai_tool_function_strict_enabled())
-        finally:
-            if prev_t is None:
-                os.environ.pop("AIA_TOOL_FUNCTION_STRICT", None)
-            else:
-                os.environ["AIA_TOOL_FUNCTION_STRICT"] = prev_t
-            if prev_d is None:
-                os.environ.pop("AIA_DEEPSEEK_STRICT_TOOL_MODE", None)
-            else:
-                os.environ["AIA_DEEPSEEK_STRICT_TOOL_MODE"] = prev_d
-
     def test_apply_sets_strict_on_function_tools(self) -> None:
         tools = [
             {"type": "function", "function": {"name": "get_weather", "parameters": {"type": "object", "properties": {}}}},