refactor: refactor the prompt management mechanism (#17)

src/prose/graph/prose_shorter_node.py

@@ -7,13 +7,10 @@ from langchain.schema import HumanMessage, SystemMessage
 
 from src.config.agents import AGENT_LLM_MAP
 from src.llms.llm import get_llm_by_type
+from src.prompts.template import get_prompt_template
 from src.prose.graph.state import ProseState
 
 logger = logging.getLogger(__name__)
-prompt = """
-You are an AI writing assistant that shortens existing text.
-- Use Markdown formatting when appropriate.
-"""
 
 
 def prose_shorter_node(state: ProseState):
@@ -21,7 +18,7 @@ def prose_shorter_node(state: ProseState):
     model = get_llm_by_type(AGENT_LLM_MAP["prose_writer"])
     prose_content = model.invoke(
         [
-            SystemMessage(content=prompt),
+            SystemMessage(content=get_prompt_template("prose/prose_shorter")),
             HumanMessage(content=f"The existing text is: {state['content']}"),
         ],
     )