NotImplementedError for system prompts with OpenAI completion models, refs #284

Signed-off-by: Simon Willison <swillison@gmail.com>

llm/default_plugins/openai_models.py

@@ -334,6 +334,10 @@ class Completion(Chat):
         return "OpenAI Completion: {}".format(self.model_id)
 
     def execute(self, prompt, stream, response, conversation=None):
+        if prompt.system:
+            raise NotImplementedError(
+                "System prompts are not supported for OpenAI completion models"
+            )
         messages = []
         if conversation is not None:
             for prev_response in conversation.responses:

tests/test_llm.py

@@ -344,6 +344,29 @@ def test_openai_completion(mocked_openai_completion, user_path):
     assert expected.items() <= row.items()
 
 
+def test_openai_completion_system_prompt_error():
+    runner = CliRunner()
+    result = runner.invoke(
+        cli,
+        [
+            "-m",
+            "gpt-3.5-turbo-instruct",
+            "Say this is a test",
+            "--no-stream",
+            "--key",
+            "x",
+            "--system",
+            "system prompts not allowed",
+        ],
+        catch_exceptions=False,
+    )
+    assert result.exit_code == 1
+    assert (
+        result.output
+        == "Error: System prompts are not supported for OpenAI completion models\n"
+    )
+
+
 def test_openai_completion_logprobs_stream(
     mocked_openai_completion_logprobs_stream, user_path
 ):