diff --git a/router/src/lib.rs b/router/src/lib.rs
index 3905a1ec..c0f86b11 100644
--- a/router/src/lib.rs
+++ b/router/src/lib.rs
@@ -62,7 +62,7 @@ pub(crate) struct GenerateVertexInstance {
     pub parameters: Option<GenerateParameters>,
 }
 
-#[derive(Clone, Deserialize, ToSchema, Serialize)]
+#[derive(Clone, Deserialize, ToSchema, Serialize, Default)]
 pub(crate) struct ChatRequestParameters {
     #[schema(example = "mistralai/Mistral-7B-Instruct-v0.2")]
     /// [UNUSED] ID of the model to use. See the model endpoint compatibility table for details on which models work with the Chat API.
diff --git a/router/src/server.rs b/router/src/server.rs
index 4647b150..20329e6d 100644
--- a/router/src/server.rs
+++ b/router/src/server.rs
@@ -1452,43 +1452,27 @@ async fn vertex_compatibility(
             },
             VertexInstance::Chat(instance) => {
                 let messages = instance.messages;
-                let ChatRequestParameters {
-                    model,
-                    max_tokens,
-                    seed,
-                    stop,
-                    stream,
-                    tools,
-                    tool_choice,
-                    tool_prompt,
-                    temperature,
-                    response_format,
-                    guideline,
-                    presence_penalty,
-                    frequency_penalty,
-                    top_p,
-                    top_logprobs,
-                    ..
-                } = instance.parameters.unwrap();
+                let chat_request: ChatRequestParameters = instance.parameters.unwrap_or_default();
 
-                let repetition_penalty = presence_penalty.map(|x| x + 2.0);
-                let max_new_tokens = max_tokens.or(Some(100));
-                let tool_prompt = tool_prompt
+                let repetition_penalty = chat_request.presence_penalty.map(|x| x + 2.0);
+                let max_new_tokens = chat_request.max_tokens.or(Some(100));
+                let tool_prompt = chat_request
+                    .tool_prompt
                     .filter(|s| !s.is_empty())
                     .unwrap_or_else(default_tool_prompt);
-                let stop = stop.unwrap_or_default();
+                let stop = chat_request.stop.unwrap_or_default();
                 // enable greedy only when temperature is 0
-                let (do_sample, temperature) = match temperature {
+                let (do_sample, temperature) = match chat_request.temperature {
                     Some(temperature) if temperature == 0.0 => (false, None),
                     other => (true, other),
                 };
                 let (inputs, grammar, _using_tools) = match prepare_chat_input(
                     &infer,
-                    response_format,
-                    tools,
-                    tool_choice,
+                    chat_request.response_format,
+                    chat_request.tools,
+                    chat_request.tool_choice,
                     &tool_prompt,
-                    guideline,
+                    chat_request.guideline,
                     messages,
                 ) {
                     Ok(result) => result,
@@ -1510,9 +1494,9 @@ async fn vertex_compatibility(
                         best_of: None,
                         temperature,
                         repetition_penalty,
-                        frequency_penalty,
+                        frequency_penalty: chat_request.frequency_penalty,
                         top_k: None,
-                        top_p,
+                        top_p: chat_request.top_p,
                         typical_p: None,
                         do_sample,
                         max_new_tokens,
@@ -1521,11 +1505,11 @@ async fn vertex_compatibility(
                         truncate: None,
                         watermark: false,
                         details: true,
-                        decoder_input_details: !stream,
-                        seed,
-                        top_n_tokens: top_logprobs,
+                        decoder_input_details: !chat_request.stream,
+                        seed: chat_request.seed,
+                        top_n_tokens: chat_request.top_logprobs,
                         grammar,
-                        adapter_id: model.filter(|m| *m != "tgi").map(String::from),
+                        adapter_id: chat_request.model.filter(|m| *m != "tgi").map(String::from),
                     },
                 }
             }