diff --git a/litellm/llms/oci/chat/transformation.py b/litellm/llms/oci/chat/transformation.py
index ddd9836c96a..10baa1019bf 100644
--- a/litellm/llms/oci/chat/transformation.py
+++ b/litellm/llms/oci/chat/transformation.py
@@ -132,6 +132,7 @@ class OCIChatConfig(BaseConfig):
             "logit_bias": "logitBias",
             "n": "numGenerations",
             "presence_penalty": "presencePenalty",
+            "reasoning_effort": "reasoningEffort",
             "seed": "seed",
             "stop": "stop",
             "tool_choice": "toolChoice",
@@ -150,14 +151,17 @@ class OCIChatConfig(BaseConfig):
             "response_format": "responseFormat",
         }
 
-        # Cohere param map differs from GENERIC in three ways:
+        # Cohere param map differs from GENERIC in four ways:
         # - tool_choice is unsupported
         # - stop sequences key is "stopSequences" not "stop"
         # - n (numGenerations) is GENERIC-only
+        # - reasoning_effort is GENERIC-only (CohereChatRequest v1 has no
+        #   reasoningEffort field; Cohere reasoning models like
+        #   command-a-reasoning use COHEREV2 which is a separate request type)
         self.openai_to_oci_cohere_param_map = {
             k: ("stopSequences" if k == "stop" else v)
             for k, v in self.openai_to_oci_generic_param_map.items()
-            if k not in ("tool_choice", "max_retries", "n")
+            if k not in ("tool_choice", "max_retries", "n", "reasoning_effort")
         }
 
     def get_supported_openai_params(self, model: str) -> List[str]:
diff --git a/litellm/types/llms/oci.py b/litellm/types/llms/oci.py
index ee5228ab123..22ca3fa90cf 100644
--- a/litellm/types/llms/oci.py
+++ b/litellm/types/llms/oci.py
@@ -103,6 +103,10 @@ class OCIChatRequestPayload(BaseModel):
     seed: Optional[int] = None
     frequencyPenalty: Optional[float] = None
     presencePenalty: Optional[float] = None
+    # Reasoning-token budget knob (OCI: NONE/MINIMAL/LOW/MEDIUM/HIGH).
+    # Honoured by GPT-5 family, Gemini 2.5, Grok reasoning variants,
+    # Cohere Command-A-Reasoning. Ignored by non-reasoning models.
+    reasoningEffort: Optional[str] = None
     responseFormat: Optional[Dict[str, Any]] = None
     toolChoice: Optional[Union[str, Dict[str, Any]]] = None
     logitBias: Optional[Dict[str, Any]] = None