fix(gemini): bridge reasoning_config into thinking_config for chat-completions routes

agent/transports/chat_completions.py

@@ -18,6 +18,52 @@ from agent.transports.base import ProviderTransport
 from agent.transports.types import NormalizedResponse, ToolCall, Usage
 
 
+def _build_gemini_thinking_config(model: str, reasoning_config: dict | None) -> dict | None:
+    """Translate Hermes/OpenRouter-style reasoning config to Gemini thinkingConfig.
+
+    Gemini native/cloud-code adapters do not read ``extra_body.reasoning``.
+    They only inspect ``extra_body.thinking_config`` / ``thinkingConfig`` and
+    then request thought parts with ``includeThoughts`` enabled.
+    """
+    if reasoning_config is None or not isinstance(reasoning_config, dict):
+        return None
+
+    if reasoning_config.get("enabled") is False:
+        # Gemini can hide thought parts even when internal thinking still
+        # happens; omit thinkingLevel to avoid model-specific validation quirks.
+        return {"includeThoughts": False}
+
+    effort = str(reasoning_config.get("effort", "medium") or "medium").strip().lower()
+    if effort == "none":
+        return {"includeThoughts": False}
+
+    thinking_config: Dict[str, Any] = {"includeThoughts": True}
+    normalized_model = (model or "").strip().lower()
+    if normalized_model.startswith("google/"):
+        normalized_model = normalized_model.split("/", 1)[1]
+
+    # Gemini 2.5 accepts thinkingBudget; don't guess a budget from Hermes'
+    # coarse effort levels. ``includeThoughts`` alone is enough to surface
+    # thought parts without risking request validation errors.
+    if normalized_model.startswith("gemini-2.5-"):
+        return thinking_config
+
+    if effort not in {"minimal", "low", "medium", "high", "xhigh"}:
+        effort = "medium"
+
+    # Gemini 3 Flash supports the wider level set; Gemini 3 Pro is stricter,
+    # so collapse low-end efforts to ``low`` and high-end efforts to ``high``.
+    if normalized_model.startswith(("gemini-3", "gemini-3.1")):
+        if "flash" in normalized_model:
+            thinking_config["thinkingLevel"] = "high" if effort == "xhigh" else effort
+        elif "pro" in normalized_model:
+            thinking_config["thinkingLevel"] = (
+                "high" if effort in {"high", "xhigh"} else "low"
+            )
+
+    return thinking_config
+
+
 class ChatCompletionsTransport(ProviderTransport):
     """Transport for api_mode='chat_completions'.
 
@@ -241,6 +287,7 @@ class ChatCompletionsTransport(ProviderTransport):
         is_openrouter = params.get("is_openrouter", False)
         is_nous = params.get("is_nous", False)
         is_github_models = params.get("is_github_models", False)
+        provider_name = str(params.get("provider_name") or "").strip().lower()
 
         provider_prefs = params.get("provider_preferences")
         if provider_prefs and is_openrouter:
@@ -293,6 +340,11 @@ class ChatCompletionsTransport(ProviderTransport):
         if is_qwen:
             extra_body["vl_high_resolution_images"] = True
 
+        if provider_name in {"gemini", "google-gemini-cli"}:
+            thinking_config = _build_gemini_thinking_config(model, reasoning_config)
+            if thinking_config:
+                extra_body["thinking_config"] = thinking_config
+
         # Merge any pre-built extra_body additions
         additions = params.get("extra_body_additions")
         if additions: