MCP Client Setup

Connection Settings

Open the QuantX marketplace and sign in.
Select the required server and open Connection.
Use the displayed MCP URL and authorization settings in your client.
Reconnect and run tools/list before your first tool call.

The interface masks the key on screen, but Copy includes the real key. Treat copied configuration as a secret: do not paste it into documentation, issue reports, workflow exports, or version control.

Setting	Value
Transport	MCP over Streamable HTTP
URL	Complete gateway URL from Connection; do not append a second `/mcp` path
Authorization	`Authorization: Bearer <your QuantX key>` as supplied by the marketplace
Tool arguments	Usually `{"request": {...}}`. `list_resources` takes `{}`; `read_resource` takes `{"uri": "..."}`
Connection check	MCP initialization, `tools/list`, then a small tool request

Use the public gateway, not a container address. Do not configure an identity header such as x-kratos-id yourself. Do not assume a gateway /health route exists or use one in place of MCP initialization.

Gateway URLs

Each server has its own path on the gateway:

Server	MCP URL
Dataloader	`https://quantx-api.limex.pro/mcps/dataloader`
Fama-French Replicate	`https://quantx-api.limex.pro/mcps/fama-french-replicate`
Statistical Factor Models	`https://quantx-api.limex.pro/mcps/statistical-factor-models`
Jump Models	`https://quantx-api.limex.pro/mcps/jump-models`
Wavelet Mean Reversion	`https://quantx-api.limex.pro/mcps/wavelet-mean-reversion`
EP Ratio Screener	`https://quantx-api.limex.pro/mcps/ep-ratio-screener`
Volatility Scaling Lab	`https://quantx-api.limex.pro/mcps/volatility-scaling-lab`

Your access to a given server, and the key it takes, come from the marketplace — use the connection it shows you rather than assuming a URL. A bundle URL uses /bundles/<slug>; copy its actual connection instead of inventing a slug.

Cursor

Place this complete configuration in project .cursor/mcp.json or user ~/.cursor/mcp.json. If the file already contains servers, merge the entry into its existing mcpServers object. This example connects to Volatility Scaling Lab:

{
  "mcpServers": {
    "volatility-scaling-lab": {
      "url": "https://quantx-api.limex.pro/mcps/volatility-scaling-lab",
      "headers": {
        "Authorization": "Bearer ${env:QUANTX_MCP_TOKEN}"
      }
    }
  }
}

Set QUANTX_MCP_TOKEN in the environment available to the running Cursor process, then reconnect. Its value is the key without the Bearer prefix. A variable exported in a separate terminal does not update an already running GUI process. Remote entries do not load envFile; do not put a key in an env block and expect it to become an HTTP header. See Cursor MCP configuration.

EP Ratio Screener With Provider Credentials

Use this full configuration for EP Ratio Screener. Set MASSIVE_API_KEY as well as QUANTX_MCP_TOKEN before starting Cursor:

{
  "mcpServers": {
    "ep-ratio-screener": {
      "url": "https://quantx-api.limex.pro/mcps/ep-ratio-screener",
      "headers": {
        "Authorization": "Bearer ${env:QUANTX_MCP_TOKEN}",
        "Massive-API-Key": "${env:MASSIVE_API_KEY}"
      }
    }
  }
}

For FMP cross-validation or use_fmp_screen: true, add "FMP-API-Key": "${env:FMP_API_KEY}" inside headers and set that variable. Dataloader uses the same Massive header for source: "massive"; Yahoo needs no provider header. Provider keys do not replace QuantX authorization. Keep them only on the connections that need them.

Claude Code

Claude Code uses project .mcp.json, not .cursor/mcp.json. It requires "type": "http" and expands ${NAME}, not Cursor’s ${env:NAME}:

{
  "mcpServers": {
    "volatility-scaling-lab": {
      "type": "http",
      "url": "https://quantx-api.limex.pro/mcps/volatility-scaling-lab",
      "headers": {
        "Authorization": "Bearer ${QUANTX_MCP_TOKEN}"
      }
    }
  }
}

Make the variable available before launching Claude Code. Approve the project configuration and inspect the connection with /mcp or claude mcp list. For EP Ratio Screener, change the name and URL to its entry above and add "Massive-API-Key": "${MASSIVE_API_KEY}" to headers; add "FMP-API-Key": "${FMP_API_KEY}" only when needed. See Claude Code MCP configuration.

Python FastMCP

Install FastMCP in your project environment:

python -m pip install "fastmcp>=3.2.4,<4"

Set QUANTX_MCP_TOKEN privately. This complete example defaults to Volatility Scaling Lab; set QUANTX_MCP_URL to another Connection URL when needed. A bundle URL does not tell you which servers sit behind it, so set the provider keys for any bundled tool you intend to call:

import asyncio
import os

from fastmcp import Client
from fastmcp.client.transports import StreamableHttpTransport


async def main() -> None:
    url = os.environ.get(
        "QUANTX_MCP_URL",
        "https://quantx-api.limex.pro/mcps/volatility-scaling-lab",
    )
    headers = {"Authorization": f"Bearer {os.environ['QUANTX_MCP_TOKEN']}"}
    if os.environ.get("MASSIVE_API_KEY"):
        headers["Massive-API-Key"] = os.environ["MASSIVE_API_KEY"]
    if os.environ.get("FMP_API_KEY"):
        headers["FMP-API-Key"] = os.environ["FMP_API_KEY"]
    if url.rstrip("/").endswith("/mcps/ep-ratio-screener") and "Massive-API-Key" not in headers:
        raise RuntimeError("Set MASSIVE_API_KEY for EP Ratio Screener")

    transport = StreamableHttpTransport(url=url, headers=headers)
    async with Client(transport) as client:
        tools = await client.list_tools()
        print([tool.name for tool in tools])
        result = await client.call_tool("load_skills", {"request": {}})
        print(result.structured_content)


asyncio.run(main())

The SDK handles initialization and transport negotiation. Header values contain one Bearer prefix; do not add it to the environment variable itself. This script checks discovery without querying a data provider. See FastMCP transports.

Other Clients

Use a client that supports both remote Streamable HTTP and the headers required by your selected connection. Do not assume an OAuth-only connector can use a static bearer key, or that the gateway exposes OAuth merely because your client offers it. Never remove gateway protection to accommodate a client. For Claude Desktop, use the remote-connector options supported by your installed version and the authentication method explicitly offered by the marketplace. If custom bearer or provider headers cannot be supplied, use a compatible client instead.

Direct HTTP Clients

Prefer an MCP SDK. A manually implemented client must:

Send initialize and honor the negotiated protocol version.
Send notifications/initialized before tool calls.
Set Content-Type: application/json and accept both application/json and text/event-stream.
Forward authorization and required provider headers on subsequent requests.
Reuse MCP-Session-Id only if the server returned it. The current server images use stateless HTTP; absence of a session header is not an error.
Handle JSON and SSE responses, JSON-RPC errors, and MCP isError independently of HTTP status.

Troubleshooting

Symptom	Check
`401` or `403`	Current key, access to this connection, and the header reaching the gateway
Literal `${...}` in a connection error	Unset environment variable or a configuration copied from a different client
Claude Code reports a missing `command` or skips a URL entry	Add `"type": "http"`; use `.mcp.json` and `${NAME}` syntax
Missing tool	Individual-server versus bundle naming, current `tools/list`, and hidden helper tools
EP Ratio configuration error	Massive provider header; QuantX authorization alone is insufficient
Tool validation error	The `request` envelope and the connected tool’s input schema
Stored result instead of rows	Resolve `result_id` on the server that produced it
Missing fitted state	Fit again on the same handle; a fit lasts only while the object stays loaded
`404 unknown_mcp` or `unknown_bundle`	Wrong slug, disabled entry, or a connection for the wrong environment
`429`	Respect `Retry-After`; a user’s budget is shared across server and bundle calls
`503`	Registry or entitlement service unavailable; respect `Retry-After` and retain the sanitized request ID

Report the tool name and sanitized error code. Do not include keys, copied connection JSON, personal data, or provider credentials in logs or support messages.

Overview

MCP Setup

Dataloader Server

Fama-French Replicate Server

Statistical Factor Models Server

Jump Models Server

Wavelet Mean Reversion Server

EP Ratio Screener Server

Volatility Scaling Lab Server

Connection Settings

Gateway URLs

Cursor

EP Ratio Screener With Provider Credentials

Claude Code

Python FastMCP

Other Clients

Direct HTTP Clients

Troubleshooting

​Connection Settings

​Gateway URLs

​Cursor

​EP Ratio Screener With Provider Credentials

​Claude Code

​Python FastMCP

​Other Clients

​Direct HTTP Clients

​Troubleshooting

Connection Settings

Gateway URLs

Cursor

EP Ratio Screener With Provider Credentials

Claude Code

Python FastMCP

Other Clients

Direct HTTP Clients

Troubleshooting