How to access passed headers into the tools of the mcp server.

[evanhameed99]

Can you provide a more explanatory example of how the headers can be accessed inside a tool call?

from langchain_mcp_adapters.client import MultiServerMCPClient
from langgraph.prebuilt import create_react_agent

client = MultiServerMCPClient(
    {
        "weather": {
            "transport": "streamable_http",
            "url": "http://localhost:8000/mcp",
            "headers": {
                "Authorization": "Bearer YOUR_TOKEN",
                "X-Custom-Header": "custom-value"
            },
        }
    }
)
tools = await client.get_tools()
agent = create_react_agent("openai:gpt-4.1", tools)
response = await agent.ainvoke({"messages": "what is the weather in nyc?"})