LangChain Mercury402: Treasury/FRED financial data over x402 get_endpoint_data
How to: LangChain Mercury402: Treasury/FRED financial data over x402 get_endpoint_data
Add Mercury402: Treasury/FRED financial data over x402 to LangChain
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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({
"mercury402-mcp": {
"transport": "streamable_http",
"url": "https://mcp.mercury402.com/mcp",
}
})
tools = await client.get_tools()
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02
Save the file and restart LangChain.
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03
Ask for something get_endpoint_data does. LangChain lists the server's tools on connect and calls get_endpoint_data itself — you do not invoke it by name.
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04
If nothing happens, check the server is running and that Mercury402: Treasury/FRED financial data over x402'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
Mercury402: Treasury/FRED financial data over x402 will not start until these are set, so get_endpoint_data never becomes available.
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MERCURY402_PAYER_PRIVATE_KEY -
MERCURY402_MAX_PRICE_USD
Same tool, other clients
This list was read from the server itself, by connecting to it and calling tools/list on 14 November 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.