diff --git a/rl/llm/engines.py b/rl/llm/engines.py
index 098e7d9..f08aeb8 100644
--- a/rl/llm/engines.py
+++ b/rl/llm/engines.py
@@ -74,7 +74,7 @@ def __init__(self, llm_config: LLMConfig):
         self.llm_config = llm_config
 
     def __enter__(self):
-        pass
+        return self
 
     def __exit__(self, exc_type, exc_value, traceback):
         pass
@@ -251,6 +251,7 @@ def __init__(self, llm_config: LLMConfig):
 
     def __enter__(self):
         genai.configure(api_key=rl.utils.io.getenv("GEMINI_API_KEY"))
+        return self
 
     def generate(self, prompt: ChatInput) -> InferenceOutput:
         if not isinstance(prompt, list):
@@ -325,6 +326,7 @@ def __init__(self, llm_config: LLMConfig):
 
     def __enter__(self):
         self.client = Anthropic(api_key=rl.utils.io.getenv(self.API_KEY_NAME))
+        return self
 
     def generate(self, prompt: ChatInput) -> InferenceOutput:
         """Given the input prompt, returns the generated text.
@@ -385,6 +387,7 @@ def __enter__(self):
         LOGGER.warning(
             f"Modal app {self.app_name} is ready! Took {time.time() - start_time:.2f}s"
         )
+        return self
 
     def generate(self, prompt: InferenceInput) -> InferenceOutput:
         return self.batch_generate([prompt])[0]
@@ -433,7 +436,7 @@ def __enter__(self):
         self.tokenizer = AutoTokenizer.from_pretrained(
             self.llm_config.tokenizer_name_or_path
         )
-        pass
+        return self
 
     def __exit__(self, exc_type, exc_value, traceback):
         pass
@@ -580,6 +583,7 @@ def __enter__(self):
             self.llm_config, use_async=False
         )
         self.tokenizer = self.vllm.get_tokenizer()
+        return self
 
     def __exit__(self, exc_type, exc_value, traceback):
         del self.vllm
@@ -772,6 +776,7 @@ def __enter__(self):
         self.tokenizer = AutoTokenizer.from_pretrained(
             self.llm_config.tokenizer_name_or_path
         )
+        return self
 
     def __exit__(self, exc_type, exc_value, traceback):
         del self.vllm