fix(opencode-go): emit Kimi reasoning_effort, match KimiProfile shape

The Kimi K2 branch added in the prior commit only emitted extra_body.thinking
and dropped reasoning_effort entirely. KimiProfile (api.moonshot.ai/v1) sends
both fields, and OpenCode Go proxies to the same Moonshot backend. Mirror that
shape on the Go path so /reasoning effort actually reaches Kimi.

- low/medium/high pass through verbatim
- xhigh/max clamp to high (Moonshot's max supported value)
- minimal / unknown effort → omit reasoning_effort, keep thinking on
- disabled / no config → unchanged
- DeepSeek branch unchanged

plugins/model-providers/opencode-zen/__init__.py

@@ -41,13 +41,24 @@ class OpenCodeGoProfile(ProviderProfile):
         top_level: dict[str, Any] = {}
 
         if _is_kimi_k2_model(model):
-            # Kimi K2 uses Moonshot's native binary thinking switch here, not
-            # OpenRouter's normalized extra_body.reasoning object.
-            if isinstance(reasoning_config, dict):
-                enabled = reasoning_config.get("enabled") is not False
-                extra_body["thinking"] = {
-                    "type": "enabled" if enabled else "disabled"
-                }
+            # Kimi K2 on OpenCode Go uses Moonshot's native wire shape:
+            # extra_body.thinking (binary toggle) + top-level reasoning_effort
+            # (low|medium|high). Mirrors the KimiProfile (api.moonshot.ai/v1).
+            if not isinstance(reasoning_config, dict):
+                # No config → leave server defaults alone.
+                return extra_body, top_level
+
+            enabled = reasoning_config.get("enabled") is not False
+            extra_body["thinking"] = {"type": "enabled" if enabled else "disabled"}
+
+            if not enabled:
+                return extra_body, top_level
+
+            effort = (reasoning_config.get("effort") or "").strip().lower()
+            if effort in {"xhigh", "max"}:
+                top_level["reasoning_effort"] = "high"
+            elif effort in {"low", "medium", "high"}:
+                top_level["reasoning_effort"] = effort
             return extra_body, top_level
 
         if not _is_deepseek_thinking_model(model):

tests/plugins/model_providers/test_opencode_go_profile.py

@@ -17,17 +17,17 @@ def opencode_go_profile():
 
 
 class TestOpenCodeGoKimiReasoning:
-    """Kimi K2 models use binary thinking controls on OpenCode Go."""
+    """Kimi K2 models use Moonshot's thinking + reasoning_effort shape on OpenCode Go."""
 
-    def test_high_effort_enables_thinking_without_effort(self, opencode_go_profile):
+    def test_high_effort_emits_thinking_and_effort(self, opencode_go_profile):
         extra_body, top_level = opencode_go_profile.build_api_kwargs_extras(
             reasoning_config={"enabled": True, "effort": "high"},
             model="kimi-k2.6",
         )
         assert extra_body == {"thinking": {"type": "enabled"}}
-        assert top_level == {}
+        assert top_level == {"reasoning_effort": "high"}
 
-    def test_disabled_emits_thinking_disabled(self, opencode_go_profile):
+    def test_disabled_emits_thinking_disabled_without_effort(self, opencode_go_profile):
         extra_body, top_level = opencode_go_profile.build_api_kwargs_extras(
             reasoning_config={"enabled": False},
             model="kimi-k2.6",
@@ -36,6 +36,7 @@ class TestOpenCodeGoKimiReasoning:
         assert top_level == {}
 
     def test_minimal_effort_enables_thinking_without_effort(self, opencode_go_profile):
+        # "minimal" is not a Moonshot-supported value — drop it, keep thinking on.
         extra_body, top_level = opencode_go_profile.build_api_kwargs_extras(
             reasoning_config={"enabled": True, "effort": "minimal"},
             model="kimi-k2.6",
@@ -50,14 +51,22 @@ class TestOpenCodeGoKimiReasoning:
             "max",
         ],
     )
-    def test_strong_efforts_enable_thinking_without_effort(
-        self, opencode_go_profile, effort
-    ):
-        extra_body, _ = opencode_go_profile.build_api_kwargs_extras(
+    def test_strong_efforts_clamp_to_high(self, opencode_go_profile, effort):
+        extra_body, top_level = opencode_go_profile.build_api_kwargs_extras(
             reasoning_config={"enabled": True, "effort": effort},
             model="moonshotai/kimi-k2.6",
         )
         assert extra_body == {"thinking": {"type": "enabled"}}
+        assert top_level == {"reasoning_effort": "high"}
+
+    def test_low_and_medium_pass_through(self, opencode_go_profile):
+        for effort in ("low", "medium"):
+            extra_body, top_level = opencode_go_profile.build_api_kwargs_extras(
+                reasoning_config={"enabled": True, "effort": effort},
+                model="kimi-k2.5",
+            )
+            assert extra_body == {"thinking": {"type": "enabled"}}
+            assert top_level == {"reasoning_effort": effort}
 
     def test_no_config_preserves_server_default(self, opencode_go_profile):
         extra_body, top_level = opencode_go_profile.build_api_kwargs_extras(
@@ -140,7 +149,7 @@ class TestOpenCodeGoModelGating:
 class TestOpenCodeGoFullKwargsIntegration:
     """End-to-end transport kwargs include the profile-provided controls."""
 
-    def test_kimi_reasoning_reaches_extra_body(self, opencode_go_profile):
+    def test_kimi_reasoning_reaches_extra_body_and_top_level(self, opencode_go_profile):
         from agent.transports.chat_completions import ChatCompletionsTransport
 
         kwargs = ChatCompletionsTransport().build_kwargs(
@@ -152,7 +161,7 @@ class TestOpenCodeGoFullKwargsIntegration:
             base_url="https://opencode.ai/zen/go/v1",
         )
         assert kwargs["extra_body"] == {"thinking": {"type": "enabled"}}
-        assert "reasoning_effort" not in kwargs
+        assert kwargs["reasoning_effort"] == "high"
 
     def test_deepseek_thinking_reaches_extra_body_and_top_level(
         self, opencode_go_profile