diff --git a/router/src/server.rs b/router/src/server.rs
index 2ed6fc25..d140509e 100644
--- a/router/src/server.rs
+++ b/router/src/server.rs
@@ -641,9 +641,9 @@ async fn completions(
         })
         .collect();
 
-    let mut x_compute_type = "unknown".to_string();
+    let mut x_compute_type = None;
     let mut x_compute_characters = 0u32;
-    let mut x_accel_buffering = "no".to_string();
+    let mut x_accel_buffering = None;
 
     if stream {
         let mut response_streams = FuturesOrdered::new();
@@ -705,29 +705,28 @@ async fn completions(
                     }
                 });
 
-                (index, header_rx, sse_rx)
+                (header_rx, sse_rx)
             };
             response_streams.push_back(generate_future);
         }
 
         let mut all_rxs = vec![];
 
-        while let Some((index, header_rx, sse_rx)) = response_streams.next().await {
+        while let Some((header_rx, sse_rx)) = response_streams.next().await {
             all_rxs.push(sse_rx);
 
             // get the headers from the first response of each stream
             let headers = header_rx.await.expect("Failed to get headers");
-            if index == 0 {
+            if x_compute_type.is_none() {
                 x_compute_type = headers
                     .get("x-compute-type")
                     .and_then(|v| v.to_str().ok())
-                    .unwrap_or("unknown")
-                    .to_string();
+                    .map(|v| v.to_string());
+
                 x_accel_buffering = headers
                     .get("x-accel-buffering")
                     .and_then(|v| v.to_str().ok())
-                    .unwrap_or("no")
-                    .to_string();
+                    .map(|v| v.to_string());
             }
             x_compute_characters += headers
                 .get("x-compute-characters")
@@ -737,9 +736,13 @@ async fn completions(
         }
 
         let mut headers = HeaderMap::new();
-        headers.insert("x-compute-type", x_compute_type.parse().unwrap());
+        if let Some(x_compute_type) = x_compute_type {
+            headers.insert("x-compute-type", x_compute_type.parse().unwrap());
+        }
         headers.insert("x-compute-characters", x_compute_characters.into());
-        headers.insert("x-accel-buffering", x_accel_buffering.parse().unwrap());
+        if let Some(x_accel_buffering) = x_accel_buffering {
+            headers.insert("x-accel-buffering", x_accel_buffering.parse().unwrap());
+        }
 
         // now sink the sse streams into a single stream and remove the ones that are done
         let stream: AsyncStream<Result<Event, Infallible>, _> = async_stream::stream! {
@@ -806,13 +809,20 @@ async fn completions(
         let choices = generate_responses
             .into_iter()
             .map(|(index, headers, Json(generation))| {
-                let details = generation.details.unwrap_or_default();
-                if index == 0 {
+                let details = generation.details.ok_or((
+                    // this should never happen but handle if details are missing unexpectedly
+                    StatusCode::INTERNAL_SERVER_ERROR,
+                    Json(ErrorResponse {
+                        error: "No details in generation".to_string(),
+                        error_type: "no details".to_string(),
+                    }),
+                ))?;
+
+                if x_compute_type.is_none() {
                     x_compute_type = headers
                         .get("x-compute-type")
                         .and_then(|v| v.to_str().ok())
-                        .unwrap_or("unknown")
-                        .to_string();
+                        .map(|v| v.to_string());
                 }
 
                 // accumulate headers and usage from each response
@@ -857,14 +867,15 @@ async fn completions(
                 completion_tokens += details.generated_tokens;
                 total_tokens += details.prefill.len() as u32 + details.generated_tokens;
 
-                CompletionComplete {
+                Ok(CompletionComplete {
                     finish_reason: details.finish_reason.to_string(),
                     index: index as u32,
                     logprobs: None,
                     text: generation.generated_text,
-                }
+                })
             })
-            .collect::<Vec<_>>();
+            .collect::<Result<Vec<_>, _>>()
+            .map_err(|(status, Json(err))| (status, Json(err)))?;
 
         let response = Completion {
             id: "".to_string(),
@@ -886,7 +897,9 @@ async fn completions(
 
         // headers similar to `generate` but aggregated
         let mut headers = HeaderMap::new();
-        headers.insert("x-compute-type", x_compute_type.parse().unwrap());
+        if let Some(x_compute_type) = x_compute_type {
+            headers.insert("x-compute-type", x_compute_type.parse().unwrap());
+        }
         headers.insert("x-compute-characters", x_compute_characters.into());
         headers.insert("x-total-time", x_total_time.into());
         headers.insert("x-validation-time", x_validation_time.into());
@@ -895,8 +908,9 @@ async fn completions(
         headers.insert("x-time-per-token", x_time_per_token.into());
         headers.insert("x-prompt-tokens", x_prompt_tokens.into());
         headers.insert("x-generated-tokens", x_generated_tokens.into());
-        headers.insert("x-accel-buffering", x_accel_buffering.parse().unwrap());
-
+        if let Some(x_accel_buffering) = x_accel_buffering {
+            headers.insert("x-accel-buffering", x_accel_buffering.parse().unwrap());
+        }
         Ok((headers, Json(response)).into_response())
     }
 }