Use field names in message history instead of explanations

Author: zsimjee

guardrails/run.py

@@ -308,7 +308,7 @@ def prepare(
                     api, instructions, prompt
                 )
             else:
-                raise ValueError("Prompt or message history must be provided.")
+                raise ValueError("'prompt' or 'msg_history' must be provided.")
 
             action.log(
                 message_type="info",
@@ -367,7 +367,7 @@ def call(
                 except Exception:
                     llm_response = api(prompt.source)
             else:
-                raise ValueError("Prompt or message history must be provided.")
+                raise ValueError("'prompt' or 'msg_history' must be provided.")
 
             action.log(
                 message_type="info",
@@ -695,7 +695,7 @@ async def async_call(
                 except Exception:
                     llm_response = await api(prompt.source)
             else:
-                raise ValueError("Output, prompt or message history must be provided.")
+                raise ValueError("'output', 'prompt' or 'msg_history' must be provided.")
 
             action.log(
                 message_type="info",