fix(llm): DeepSeek strict tools via function.strict, not extra_body

Match DeepSeek Tool Calls docs: set strict:true on each tools[].function.
Remove non-documented strict_tool_mode extra_body. Keep AIA_DEEPSEEK_STRICT_TOOL_MODE=0 to opt out.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_openai_chat_strict_tool_mode.py

@@ -1,4 +1,4 @@
-"""DeepSeek OpenAI-compat: strict_tool_mode via extra_body."""
+"""DeepSeek: per-function ``strict: true`` on tools (official Tool Calls / strict Beta)."""
 
 from __future__ import annotations
 
@@ -6,15 +6,15 @@ import os
 import unittest
 
 from svc.llm.transports.openai_chat_completions import (
-    _deepseek_strict_tool_mode_enabled,
-    _merge_deepseek_strict_tool_mode_extra_body,
+    _apply_deepseek_strict_tools,
+    _deepseek_strict_tools_enabled,
 )
 
 
-class DeepseekStrictToolModeTests(unittest.TestCase):
+class DeepseekStrictToolsTests(unittest.TestCase):
     def test_enabled_when_deepseek_in_base_url(self) -> None:
         self.assertTrue(
-            _deepseek_strict_tool_mode_enabled(
+            _deepseek_strict_tools_enabled(
                 base_url="https://api.deepseek.com/v1",
                 model="deepseek-chat",
             )
@@ -25,7 +25,7 @@ class DeepseekStrictToolModeTests(unittest.TestCase):
         try:
             os.environ["AIA_DEEPSEEK_STRICT_TOOL_MODE"] = "0"
             self.assertFalse(
-                _deepseek_strict_tool_mode_enabled(
+                _deepseek_strict_tools_enabled(
                     base_url="https://api.deepseek.com/v1",
                     model="x",
                 )
@@ -36,54 +36,28 @@ class DeepseekStrictToolModeTests(unittest.TestCase):
             else:
                 os.environ["AIA_DEEPSEEK_STRICT_TOOL_MODE"] = prev
 
-    def test_merge_sets_extra_body_strict_tool_mode(self) -> None:
-        kwargs: dict = {"model": "m", "messages": [], "stream": False, "tools": [{"type": "function"}]}
-        _merge_deepseek_strict_tool_mode_extra_body(
-            kwargs,
-            base_url="https://api.deepseek.com/v1",
-            model="deepseek-chat",
-            use_tools=True,
-        )
-        self.assertEqual(kwargs.get("extra_body"), {"strict_tool_mode": True})
+    def test_apply_sets_strict_on_function_tools(self) -> None:
+        tools = [
+            {"type": "function", "function": {"name": "get_weather", "parameters": {"type": "object", "properties": {}}}},
+            {"type": "not_function", "x": 1},
+        ]
+        out = _apply_deepseek_strict_tools(tools)
+        self.assertIsNotNone(out)
+        assert out is not None
+        self.assertTrue(out[0]["function"]["strict"])
+        self.assertEqual(out[1].get("type"), "not_function")
+        self.assertNotIn("strict", out[1])
+        # input not mutated
+        self.assertNotIn("strict", tools[0].get("function", {}))
 
-    def test_merge_preserves_existing_extra_body(self) -> None:
-        kwargs: dict = {
-            "model": "m",
-            "messages": [],
-            "stream": False,
-            "tools": [{"type": "function"}],
-            "extra_body": {"thinking": {"type": "disabled"}},
-        }
-        _merge_deepseek_strict_tool_mode_extra_body(
-            kwargs,
-            base_url="https://api.deepseek.com",
-            model="deepseek-reasoner",
-            use_tools=True,
-        )
-        self.assertEqual(
-            kwargs["extra_body"],
-            {"thinking": {"type": "disabled"}, "strict_tool_mode": True},
-        )
+    def test_apply_skips_non_deepseek_not_tested_here(self) -> None:
+        out = _apply_deepseek_strict_tools([])
+        self.assertEqual(out, [])
 
-    def test_merge_skips_without_tools(self) -> None:
-        kwargs: dict = {"model": "m", "messages": [], "stream": False}
-        _merge_deepseek_strict_tool_mode_extra_body(
-            kwargs,
-            base_url="https://api.deepseek.com/v1",
-            model="deepseek-chat",
-            use_tools=False,
-        )
-        self.assertNotIn("extra_body", kwargs)
-
-    def test_merge_skips_non_deepseek(self) -> None:
-        kwargs: dict = {"model": "m", "messages": [], "stream": False, "tools": [{"type": "function"}]}
-        _merge_deepseek_strict_tool_mode_extra_body(
-            kwargs,
-            base_url="https://api.openai.com/v1",
-            model="gpt-4o-mini",
-            use_tools=True,
-        )
-        self.assertNotIn("extra_body", kwargs)
+    def test_apply_handles_missing_function_dict(self) -> None:
+        out = _apply_deepseek_strict_tools([{"type": "function"}])
+        assert out is not None
+        self.assertEqual(out[0]["function"], {"strict": True})
 
 
 if __name__ == "__main__":