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LangChain Nonlinear Calendar date_lookup

How to: LangChain Nonlinear Calendar date_lookup

client:LangChain transport:streamable-http tool:date_lookup

Add Nonlinear Calendar to LangChain

  1. 01

    Open pip install langchain-mcp-adapters and merge this in. Keep any servers already there.

from langchain_mcp_adapters.client import MultiServerMCPClient

client = MultiServerMCPClient({
        "balance-engine": {
            "transport": "streamable_http",
            "url": "https://balance-engine.vercel.app/api/mcp",
        }
})

tools = await client.get_tools()
  1. 02

    Save the file and restart LangChain.

  2. 03

    Ask for something date_lookup does. LangChain lists the server's tools on connect and calls date_lookup itself — you do not invoke it by name.

  3. 04

    If nothing happens, check the server is running and that Nonlinear Calendar's identifier in your config matches the one above exactly.

get_tools() returns the server's tools as LangChain tools, ready for an agent. LangChain docs

Set these first

Nonlinear Calendar will not start until these are set, so date_lookup never becomes available.

  • BALANCE_API_KEY
  • BALANCE_ENGINE_API_BASE

Same tool, other clients

This list was read from the server itself, by connecting to it and calling tools/list on 24 September 2026. It is what the server actually exposes, not what its listing claims.

Mutating and Read-only are read off each tool's name, not its schema — a hint, not a guarantee. The registry stores tool names only; connect the server for its live schemas.