fix(providers): guard chat_with_retry against explicit None max_tokens (#3102)

nanobot/providers/base.py

@@ -512,10 +512,14 @@ class LLMProvider(ABC):
         on_retry_wait: Callable[[str], Awaitable[None]] | None = None,
     ) -> LLMResponse:
         """Call chat_stream() with retry on transient provider failures."""
-        if max_tokens is self._SENTINEL:
+        if max_tokens is self._SENTINEL or max_tokens is None:
             max_tokens = self.generation.max_tokens
-        if temperature is self._SENTINEL:
+        if max_tokens is None:
+            max_tokens = GenerationSettings.max_tokens
+        if temperature is self._SENTINEL or temperature is None:
             temperature = self.generation.temperature
+        if temperature is None:
+            temperature = GenerationSettings.temperature
         if reasoning_effort is self._SENTINEL:
             reasoning_effort = self.generation.reasoning_effort
 
@@ -549,12 +553,20 @@ class LLMProvider(ABC):
 
         Parameters default to ``self.generation`` when not explicitly passed,
         so callers no longer need to thread temperature / max_tokens /
-        reasoning_effort through every layer.
+        reasoning_effort through every layer. Explicit ``None`` is also
+        normalized to the provider's generation defaults, with a final fallback
+        to :class:`GenerationSettings` class defaults so that downstream
+        ``_build_kwargs`` never sees ``None`` for ``max_tokens`` / ``temperature``
+        (which would crash ``max(1, max_tokens)``).
         """
-        if max_tokens is self._SENTINEL:
+        if max_tokens is self._SENTINEL or max_tokens is None:
             max_tokens = self.generation.max_tokens
-        if temperature is self._SENTINEL:
+        if max_tokens is None:
+            max_tokens = GenerationSettings.max_tokens
+        if temperature is self._SENTINEL or temperature is None:
             temperature = self.generation.temperature
+        if temperature is None:
+            temperature = GenerationSettings.temperature
         if reasoning_effort is self._SENTINEL:
             reasoning_effort = self.generation.reasoning_effort
 

tests/providers/test_provider_retry.py

@@ -521,3 +521,59 @@ async def test_persistent_retry_emits_terminal_progress_on_identical_error_limit
 
     assert response.finish_reason == "error"
     assert progress[-1] == "Persistent retry stopped after 10 identical errors."
+
+
+@pytest.mark.asyncio
+async def test_chat_with_retry_normalizes_explicit_none_max_tokens() -> None:
+    """Explicit max_tokens=None must fall back to generation defaults.
+
+    Regression for #3102: callers that construct AgentRunSpec with
+    max_tokens=None propagate None into chat_with_retry, which used to
+    reach ``_build_kwargs`` and crash on ``max(1, None)``.
+    """
+    provider = ScriptedProvider([LLMResponse(content="ok")])
+
+    response = await provider.chat_with_retry(
+        messages=[{"role": "user", "content": "hi"}],
+        max_tokens=None,
+        temperature=None,
+    )
+
+    assert response.content == "ok"
+    # Generation settings default to 4096 / 0.7; explicit None should
+    # have been replaced before reaching chat().
+    assert provider.last_kwargs["max_tokens"] == 4096
+    assert provider.last_kwargs["temperature"] == 0.7
+
+
+@pytest.mark.asyncio
+async def test_chat_with_retry_hard_fallback_when_generation_max_tokens_is_none() -> None:
+    """Final fallback: even if provider.generation.max_tokens is None,
+    chat() must receive the GenerationSettings class default (not None)."""
+    provider = ScriptedProvider([LLMResponse(content="ok")])
+    # Bypass the dataclass type hint by constructing with None explicitly.
+    provider.generation = GenerationSettings(max_tokens=None, temperature=None)  # type: ignore[arg-type]
+
+    response = await provider.chat_with_retry(
+        messages=[{"role": "user", "content": "hi"}],
+    )
+
+    assert response.content == "ok"
+    assert provider.last_kwargs["max_tokens"] == GenerationSettings.max_tokens
+    assert provider.last_kwargs["temperature"] == GenerationSettings.temperature
+
+
+@pytest.mark.asyncio
+async def test_chat_stream_with_retry_normalizes_explicit_none_max_tokens() -> None:
+    """chat_stream_with_retry must apply the same None-guard as chat_with_retry."""
+    provider = ScriptedProvider([LLMResponse(content="ok")])
+
+    response = await provider.chat_stream_with_retry(
+        messages=[{"role": "user", "content": "hi"}],
+        max_tokens=None,
+        temperature=None,
+    )
+
+    assert response.content == "ok"
+    assert provider.last_kwargs["max_tokens"] == 4096
+    assert provider.last_kwargs["temperature"] == 0.7