fix(providers): wire MiMo to thinking_type to allow disabling reasoning (#3585)

The hosted Xiaomi MiMo API accepts {"thinking": {"type": "enabled"|"disabled"}}
to toggle reasoning, which is exactly the shape produced by the existing
thinking_type style. The xiaomi_mimo ProviderSpec just needed to opt in.

Before this fix, setting reasoning_effort="none" had no effect on MiMo
because no thinking_style was configured, so the disable signal never
reached the server. Default-on models (mimo-v2.5-pro and friends) kept
reasoning regardless of user configuration.

Source: https://platform.xiaomimimo.com/docs/en-US/api/chat/openai-api

Co-authored with Claude Opus 4.7. Strategy and review via Claude Desktop,
implementation via Claude Code.

nanobot/providers/registry.py

@@ -368,6 +368,8 @@ PROVIDERS: tuple[ProviderSpec, ...] = (
         reasoning_as_content=True,
     ),
     # Xiaomi MIMO (小米): OpenAI-compatible API
+    # Hosted API (api.xiaomimimo.com) accepts {"thinking": {"type": "enabled"|"disabled"}}
+    # to toggle reasoning, matching the existing thinking_type style.
     ProviderSpec(
         name="xiaomi_mimo",
         keywords=("xiaomi_mimo", "mimo"),
@@ -375,6 +377,7 @@ PROVIDERS: tuple[ProviderSpec, ...] = (
         display_name="Xiaomi MIMO",
         backend="openai_compat",
         default_api_base="https://api.xiaomimimo.com/v1",
+        thinking_style="thinking_type",
     ),
     # LongCat: OpenAI-compatible API
     ProviderSpec(

tests/providers/test_xiaomi_mimo_thinking.py

@@ -0,0 +1,121 @@
+"""Tests for Xiaomi MiMo thinking-mode toggle via reasoning_effort.
+
+The hosted Xiaomi MiMo API (api.xiaomimimo.com) accepts
+``{"thinking": {"type": "enabled"|"disabled"}}`` in the request body
+to toggle reasoning. Source: https://platform.xiaomimimo.com/docs/en-US/api/chat/openai-api
+
+The thinking_type style already exists in _THINKING_STYLE_MAP and
+produces exactly this shape, so MiMo just needs to opt in via its
+ProviderSpec.thinking_style.
+
+Default thinking behavior per Xiaomi docs:
+  - mimo-v2-flash: disabled
+  - mimo-v2.5-pro, mimo-v2.5, mimo-v2-pro, mimo-v2-omni: enabled
+
+Without an explicit reasoning_effort, nanobot must not send the
+thinking field so the provider default is preserved (issue #3585).
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+from nanobot.config.schema import ProvidersConfig
+from nanobot.providers.openai_compat_provider import OpenAICompatProvider
+from nanobot.providers.registry import PROVIDERS
+
+
+def _mimo_spec():
+    """Return the registered xiaomi_mimo ProviderSpec."""
+    specs = {s.name: s for s in PROVIDERS}
+    return specs["xiaomi_mimo"]
+
+
+def _mimo_provider() -> OpenAICompatProvider:
+    return OpenAICompatProvider(
+        api_key="test-key",
+        default_model="mimo-v2.5-pro",
+        spec=_mimo_spec(),
+    )
+
+
+def _simple_messages() -> list[dict[str, Any]]:
+    return [{"role": "user", "content": "hello"}]
+
+
+# ---------------------------------------------------------------------------
+# Registry
+# ---------------------------------------------------------------------------
+
+
+def test_xiaomi_mimo_config_field_exists():
+    """ProvidersConfig should expose a xiaomi_mimo field."""
+    config = ProvidersConfig()
+    assert hasattr(config, "xiaomi_mimo")
+
+
+def test_xiaomi_mimo_uses_thinking_type_style():
+    """MiMo hosted API uses {"thinking": {"type": ...}}, the thinking_type style."""
+    spec = _mimo_spec()
+    assert spec.thinking_style == "thinking_type"
+    assert spec.backend == "openai_compat"
+    assert spec.default_api_base == "https://api.xiaomimimo.com/v1"
+
+
+# ---------------------------------------------------------------------------
+# _build_kwargs wire-format
+# ---------------------------------------------------------------------------
+
+
+def test_mimo_reasoning_effort_none_disables_thinking():
+    """reasoning_effort="none" should send thinking.type="disabled"."""
+    provider = _mimo_provider()
+    kwargs = provider._build_kwargs(
+        messages=_simple_messages(),
+        tools=None, model=None, max_tokens=100,
+        temperature=0.7, reasoning_effort="none", tool_choice=None,
+    )
+    # reasoning_effort itself must NOT be sent when value is "none"
+    assert "reasoning_effort" not in kwargs
+    # The disable signal must be in extra_body
+    assert kwargs["extra_body"] == {"thinking": {"type": "disabled"}}
+
+
+def test_mimo_reasoning_effort_medium_enables_thinking():
+    """reasoning_effort="medium" should send thinking.type="enabled"."""
+    provider = _mimo_provider()
+    kwargs = provider._build_kwargs(
+        messages=_simple_messages(),
+        tools=None, model=None, max_tokens=100,
+        temperature=0.7, reasoning_effort="medium", tool_choice=None,
+    )
+    assert kwargs.get("reasoning_effort") == "medium"
+    assert kwargs["extra_body"] == {"thinking": {"type": "enabled"}}
+
+
+def test_mimo_reasoning_effort_low_enables_thinking():
+    """Any non-none/minimal effort enables thinking."""
+    provider = _mimo_provider()
+    kwargs = provider._build_kwargs(
+        messages=_simple_messages(),
+        tools=None, model=None, max_tokens=100,
+        temperature=0.7, reasoning_effort="low", tool_choice=None,
+    )
+    assert kwargs["extra_body"] == {"thinking": {"type": "enabled"}}
+
+
+def test_mimo_reasoning_effort_unset_preserves_provider_default():
+    """When reasoning_effort is None, no thinking field is sent.
+
+    This preserves the provider default (varies by model per Xiaomi docs).
+    Required so that omitting the config field behaves the same as before
+    this fix — no behavior change for users who never set reasoning_effort.
+    """
+    provider = _mimo_provider()
+    kwargs = provider._build_kwargs(
+        messages=_simple_messages(),
+        tools=None, model=None, max_tokens=100,
+        temperature=0.7, reasoning_effort=None, tool_choice=None,
+    )
+    assert "reasoning_effort" not in kwargs
+    assert "extra_body" not in kwargs