openapi toolkit does not replace variable values from API specification parameters

[sumeetk8]

Checked other resources

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

Example Code

import os
import yaml
from langchain_community.agent_toolkits.openapi import planner
from langchain_openai import ChatOpenAI
from langchain_community.agent_toolkits.openapi.spec import reduce_openapi_spec
from langchain_community.utilities.requests import RequestsWrapper
from dotenv import load_dotenv

Load environment variables

load_dotenv()

OPENAI_API_KEY = os.getenv("OPENAI_API_KEY")

Load Swagger Specification

with open("waapi.yaml", "r", encoding='utf8') as f:
raw_waapi_api_spec = yaml.load(f, Loader=yaml.Loader)

Add the host from environment variable

waapi_host = os.getenv("WAAPI_HOST")
if waapi_host:
raw_waapi_api_spec["servers"] = [{"url": waapi_host}]

Reduce the OpenAPI spec

waapi_api_spec = reduce_openapi_spec(raw_waapi_api_spec)

Define the LangChain Agent

llm = ChatOpenAI(model_name="gpt-4", temperature=0.0, api_key=OPENAI_API_KEY)

Set headers for the requests

headers = {"X-API-KEY": os.getenv("WAAPI_API_KEY")}
requests_wrapper = RequestsWrapper(headers=headers)

NOTE: set allow_dangerous_requests manually for security concern https://python.langchain.com/docs/security

waapi_agent = planner.create_openapi_agent(
waapi_api_spec,
requests_wrapper,
llm,
allow_dangerous_requests=False,
)

Interactive loop for user input

print("Interactive WAAPI Agent. Enter your query below. Press Enter on an empty line to exit.")

while True:
user_query = input("Your query: ").strip()
if not user_query:
print("Exiting the program. Goodbye!")
break

try:
    response = waapi_agent.invoke(user_query)
    print(f"Response: {response}")
except Exception as e:
    print(f"An error occurred: {e}")

Error Message and Stack Trace (if applicable)

No response

Description

I want to use langchain to read an API specification and figure out the sequence of API calls that would be required to create a new user account based on the API spec given below -
https://waha.devlike.pro/swagger/openapi.json

System Info

System Information

OS: Windows
OS Version: 10.0.26100
Python Version: 3.13.1 (tags/v3.13.1:0671451, Dec 3 2024, 19:06:28) [MSC v.1942 64 bit (AMD64)]

Package Information

langchain_core: 0.3.28
langchain: 0.3.13
langchain_community: 0.3.13
langsmith: 0.2.4
langchain_mistralai: 0.2.4
langchain_openai: 0.2.14
langchain_text_splitters: 0.3.4

Optional packages not installed

langserve

Other Dependencies

aiohttp: 3.11.11
async-timeout: Installed. No version info available.
dataclasses-json: 0.6.7
httpx: 0.28.1
httpx-sse: 0.4.0
jsonpatch: 1.33
langsmith-pyo3: Installed. No version info available.
numpy: 2.2.1
openai: 1.58.1
orjson: 3.10.12
packaging: 24.2
pydantic: 2.10.4
pydantic-settings: 2.7.0
PyYAML: 6.0.2
requests: 2.32.3
requests-toolbelt: 1.0.0
SQLAlchemy: 2.0.36
tenacity: 9.0.0
tiktoken: 0.8.0
tokenizers: 0.21.0
typing-extensions: 4.12.2