docs/concepts/prompt_templates/

[giscus[bot]]

docs/concepts/prompt_templates/

Prompt templates help to translate user input and parameters into instructions for a language model.

https://python.langchain.com/docs/concepts/prompt_templates/

[nagabharath2003]

prompt_template = ChatPromptTemplate([
("system", "You are a helpful assistant"),
("placeholder", "{msgs}") # <-- This is the changed part
])

[cjhhjenny1]

prompt_template = ChatPromptTemplate.from_messages(
[
("system", "You are a helpful assistant"), # system
("placeholder", "{msgs}") # palceholder
] # <-- This is the changed part
)

[DavidZeng-cpu]

prompt_template = ChatPromptTemplate([
SystemMessage("You are a helpful translator to Translate the user sentence to {Language}."),
MessagesPlaceholder("msgs")
])

prompt=prompt_template.invoke({"Language":"Chinese", "msgs":[HumanMessage("I am fine, thank you.")]})

result = llm.invoke(prompt)
print(result.content)
###########################################
I have a question abover. The variable "Language" can not take effect when running. It seems like that this variable was not passed to chat model. The model just translate the HumanMessage but not into the specific language I signified above.

[dagongge]

I try to run your code, and get the same problem.When i print "prompt", the result is :
messages=[SystemMessage(content='You are a helpful translator to Translate the user sentence to {language}.', additional_kwargs={}, response_metadata={}), HumanMessage(content='I am fine, thank you.', additional_kwargs={}, response_metadata={})].
So i think SystemMessage can't pass the parameter?Just a guess.

[dagongge]

You can use " ("system", "You are a helpful translator to Translate the user sentence to {language}.")" to replace "SystemMessage("You are a helpful translator to Translate the user sentence to {Language}."),".

[Joseluisbarbosa]

ChatPromptTemplate takes SystemMessages as a text message and doesn't treat {Languages} as a parameter. For this, it's better to use ChatPromptTemplate.from_messages and send a SystemMessagePromptTemplate inside, which would treat {Language} as a parameter. It would look something like this:

prompt_template = ChatPromptTemplate.from_messages([
SystemMessagePromptTemplate.from_template("You are a helpful translator to translate the user sentence to {Language}.")),
MessagesPlaceholder("msgs")
])

prompt = prompt_template.format_prompt(Language="Chinese", msgs=[HumanMessage("I am fine, thank you.")])