Missing key error - Using PromptTemplate and GraphCypherQAChain.

[pierreoberholzer]

Checked other resources

• [X] I added a very descriptive title to this issue.
• [X] I searched the LangChain documentation with the integrated search.
• [X] I used the GitHub search to find a similar question and didn't find it.
• [X] I am sure that this is a bug in LangChain rather than my code.
• [X] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

Example Code

from langchain.prompts.prompt import PromptTemplate
from langchain.chains import GraphCypherQAChain


CYPHER_QA_TEMPLATE = """

You're an AI cook formulating Cypher statements to navigate through a recipe database.

Schema: {schema}

Examples: {examples}

Question: {question}

"""

CYPHER_GENERATION_PROMPT = PromptTemplate(
    input_variables=["schema","examples","question"],
    template = CYPHER_QA_TEMPLATE)
    
model = ChatOpenAI(temperature=0, model_name = "gpt-4-0125-preview")
chain = GraphCypherQAChain.from_llm(graph=graph, llm=model, verbose=True, validate_cypher = True, cypher_prompt = CYPHER_GENERATION_PROMPT)
res = chain.invoke({"schema": graph.schema,"examples" : examples,"question":question})

Error Message and Stack Trace (if applicable)

> Entering new GraphCypherQAChain chain...
Traceback (most recent call last):
  File "/Users/<path_to_my_project>/src/text2cypher_langchain.py", line 129, in <module>
    res = chain.invoke({"schema": graph.schema,"examples" : examples,"question":question})
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/<path_to_my_project>/venv/lib/python3.11/site-packages/langchain/chains/base.py", line 166, in invoke
    raise e
  File "/Users/<path_to_my_project>/venv/lib/python3.11/site-packages/langchain/chains/base.py", line 154, in invoke
    self._validate_inputs(inputs)
  File "/Users/<path_to_my_project>/venv/lib/python3.11/site-packages/langchain/chains/base.py", line 284, in _validate_inputs
    raise ValueError(f"Missing some input keys: {missing_keys}")
ValueError: Missing some input keys: {'query'}

Description

I'm getting a missing key error when passing custom arguments in PromptTemplate and GraphCypherQAChain. This seems similar to #19560 now closed.

System Info

• langchain==0.2.7
• MacOS 13.6.7 (Ventura)
• python 3.11.4