diff --git a/astrai/inference/engine.py b/astrai/inference/engine.py
index 29e777c..95c878f 100644
--- a/astrai/inference/engine.py
+++ b/astrai/inference/engine.py
@@ -9,7 +9,7 @@ from typing import Any, AsyncGenerator, Dict, Generator, List, Optional, Union
 import torch
 import torch.nn as nn
 
-from astrai.inference.scheduler import InferenceScheduler
+from astrai.inference.scheduler import _STOP, InferenceScheduler
 from astrai.tokenize import AutoTokenizer
 
 logger = logging.getLogger(__name__)
@@ -84,15 +84,15 @@ class _Result:
         """Appends a token to the result buffer.
 
         In non-streaming mode, tokens are concatenated into results[idx].
-        The sentinel "[DONE]" marks a task as complete.
+        The sentinel _STOP marks a task as complete.
 
         Args:
-            token: The decoded token string, or "[DONE]" sentinel.
+            token: The decoded token string, or _STOP sentinel.
             idx: Index of the generation task this token belongs to.
         """
         with self._lock:
             self.tokens.append(token)
-            if token != "[DONE]":
+            if token is not _STOP:
                 self.results[idx] += token
             else:
                 if not self._done[idx]:
@@ -349,14 +349,13 @@ class InferenceEngine:
                 while True:
                     tokens = result.pop_all()
                     for token in tokens:
-                        if token == "[DONE]":
+                        if token is _STOP:
                             return
                         yield token
                     if not result.wait(timeout=0.05):
                         pass
-            except GeneratorExit:
+            finally:
                 self.scheduler.remove_task(task_id)
-                raise
 
         return gen()
 
diff --git a/astrai/inference/scheduler.py b/astrai/inference/scheduler.py
index 9f492d4..e32bb4a 100644
--- a/astrai/inference/scheduler.py
+++ b/astrai/inference/scheduler.py
@@ -12,6 +12,8 @@ from torch import Tensor
 from astrai.model.automodel import AutoModel
 from astrai.tokenize import AutoTokenizer
 
+_STOP = object()
+
 
 class _RadixNode:
     """Internal node for the radix tree prefix cache.
@@ -290,9 +292,6 @@ def apply_sampling_strategies(
 ) -> Tensor:
     """Applies temperature scaling, top-k filtering, and top-p (nucleus) filtering.
 
-    Operates on a clone of the input logits to avoid in-place modification
-    of the inference tensor.
-
     Args:
         logits: Raw logits tensor of shape (batch, vocab_size).
         temperature: Temperature scaling factor (1.0 = no scaling).
@@ -704,7 +703,7 @@ class InferenceScheduler:
         for t in tasks:
             if t.is_finished(self.tokenizer.stop_ids):
                 if t.stream_callback:
-                    t.stream_callback("[DONE]")
+                    t.stream_callback(_STOP)
 
     def _run_generation_loop(self) -> None:
         """Main generation loop run in a daemon thread.
diff --git a/astrai/inference/server.py b/astrai/inference/server.py
index 23e3334..0cd41bc 100644
--- a/astrai/inference/server.py
+++ b/astrai/inference/server.py
@@ -154,8 +154,6 @@ async def chat_completion(request: ChatCompletionRequest):
 
         async def event_stream():
             async for token in agen:
-                if token == "[DONE]":
-                    break
                 yield f"data: {json.dumps({'choices': [{'delta': {'content': token}}]})}\n\n"
             yield "data: [DONE]\n\n"
 
@@ -224,8 +222,6 @@ async def generate(
 
         async def text_stream():
             async for token in agen:
-                if token == "[DONE]":
-                    break
                 yield token + "\n"
 
         return StreamingResponse(text_stream(), media_type="text/plain")