fix(vision): honor supports_vision_tool_messages=False in tool-result media gates

A ProviderProfile that declares supports_vision_tool_messages=False accepts
images in user messages but rejects list-type tool-result content with 400
(xiaomi/MiMo "text is not set"). supports_vision=True alone used to flip
_supports_media_in_tool_results to True, and a vision-capable capability
lookup could re-open _should_use_native_vision_fast_path — so the native
multimodal envelope landed in a role:tool message and 400'd every turn.

Both gates now go through one _profile_rejects_tool_media() veto.

Refs #89981

(cherry picked from commit daed88f940a6a475f12bb435498e48181da60f4d, trimmed)

tests/tools/test_vision_native_fast_path.py

@@ -90,6 +90,30 @@ class TestSupportsMediaInToolResults:
         assert _supports_media_in_tool_results("", "anything") is False
         assert _supports_media_in_tool_results(None, "anything") is False  # type: ignore[arg-type]
 
+    def test_profile_tool_message_veto_overrides_supports_vision(self):
+        """supports_vision_tool_messages=False is a hard veto even when the
+        profile declares supports_vision=True (xiaomi/MiMo 400s on list-type
+        tool-result content, #89981)."""
+        assert _supports_media_in_tool_results("xiaomi", "mimo-v2.5") is False
+
+    def test_profile_veto_applies_even_when_vision_capable_lookup_agrees(self):
+        """A capability source marking the model vision-capable must not
+        re-open the native fast path for a provider that rejects it."""
+        from tools.vision_tools import _should_use_native_vision_fast_path
+        from agent.auxiliary_client import set_runtime_main, clear_runtime_main
+        from agent import image_routing
+
+        set_runtime_main("xiaomi", "mimo-v2.5")
+        try:
+            with patch.object(
+                image_routing, "decide_image_input_mode", return_value="native"
+            ), patch.object(
+                image_routing, "_lookup_supports_vision", return_value=True
+            ):
+                assert _should_use_native_vision_fast_path() is False
+        finally:
+            clear_runtime_main()
+
 
 # ─── _build_native_vision_tool_result ────────────────────────────────────────
 

tools/vision_tools.py

@@ -1077,6 +1077,22 @@ def _resize_image_for_vision(image_path: Path, mime_type: Optional[str] = None,
 # ---------------------------------------------------------------------------
 
 
+def _profile_rejects_tool_media(provider: str) -> bool:
+    """Hard veto: the provider's ``ProviderProfile`` declares
+    ``supports_vision_tool_messages=False`` — images are accepted in user
+    messages but list-type tool-result content is rejected with 400
+    (xiaomi/MiMo "text is not set"). ``supports_vision`` alone must not
+    override this, or the multimodal tool-result envelope 400s every turn
+    and the image never enters context (#89981).
+    """
+    try:
+        from providers import get_provider_profile
+        profile = get_provider_profile(str(provider or "").strip().lower())
+        return profile is not None and profile.supports_vision_tool_messages is False
+    except Exception:
+        return False
+
+
 def _supports_media_in_tool_results(provider: str, model: str) -> bool:
     """Whether the given provider+model combination accepts image content
     inside a tool-result message.
@@ -1100,7 +1116,7 @@ def _supports_media_in_tool_results(provider: str, model: str) -> bool:
     if not isinstance(provider, str):
         return False
     p = provider.strip().lower()
-    if not p:
+    if not p or _profile_rejects_tool_media(p):
         return False
 
     # Aggregators that route to multiple vendors — assume support since
@@ -1170,6 +1186,11 @@ def _should_use_native_vision_fast_path() -> bool:
         cfg = load_config()
         if decide_image_input_mode(provider, model, cfg) != "native":
             return False
+        # The profile veto applies ahead of the capability lookup too: a
+        # model marked vision-capable by models.dev / custom_providers must
+        # not re-open the multimodal-envelope route the profile rejects.
+        if _profile_rejects_tool_media(provider):
+            return False
         return (
             _supports_media_in_tool_results(provider, model)
             or _lookup_supports_vision(provider, model, cfg) is True