fix: model arguments fixed

backend/tests/test_patched_openai_compat_provider.py

@@ -0,0 +1,62 @@
+import sys
+from pathlib import Path
+
+BACKEND_ROOT = Path(__file__).resolve().parents[1]
+REPO_ROOT = BACKEND_ROOT.parent
+NANOBOT_ROOT = REPO_ROOT / "nanobot"
+if str(BACKEND_ROOT) not in sys.path:
+    sys.path.insert(0, str(BACKEND_ROOT))
+if str(NANOBOT_ROOT) not in sys.path:
+    sys.path.insert(0, str(NANOBOT_ROOT))
+
+from app.core.llm_provider import build_llm_provider
+from app.core.nanobot import NanobotIntegration
+from app.core.patched_openai_compat_provider import PatchedOpenAICompatProvider
+
+
+def test_build_llm_provider_uses_max_completion_tokens_for_gpt5() -> None:
+    provider = build_llm_provider(
+        model="gpt-5.4-nano",
+        provider="openai",
+        api_key="test-key",
+        api_base="https://example.com/v1",
+    )
+
+    assert isinstance(provider, PatchedOpenAICompatProvider)
+    kwargs = provider._build_kwargs(
+        messages=[{"role": "user", "content": "hello"}],
+        tools=None,
+        model="gpt-5.4-nano",
+        max_tokens=5,
+        temperature=0,
+        reasoning_effort=None,
+        tool_choice=None,
+    )
+
+    assert kwargs["max_completion_tokens"] == 5
+    assert "max_tokens" not in kwargs
+
+
+def test_nanobot_provider_keeps_max_tokens_for_legacy_models() -> None:
+    integration = NanobotIntegration()
+    provider = integration._build_provider(
+        model="gpt-4o-mini",
+        provider_name="openai",
+        api_key="test-key",
+        api_base="https://example.com/v1",
+        extra_headers=None,
+    )
+
+    assert isinstance(provider, PatchedOpenAICompatProvider)
+    kwargs = provider._build_kwargs(
+        messages=[{"role": "user", "content": "hello"}],
+        tools=None,
+        model="gpt-4o-mini",
+        max_tokens=5,
+        temperature=0,
+        reasoning_effort=None,
+        tool_choice=None,
+    )
+
+    assert kwargs["max_tokens"] == 5
+    assert "max_completion_tokens" not in kwargs