Use Dutyfinch MCP with Cursor

US tariff API + MCP: HTS duty rates, Section 301 lists. Keys $19/mo; 50 free calls a day.

Remote MCP server (Streamable HTTP), nothing to install. Free: 50 free calls a day · Paid: Keys $19/mo

Set it up

Open or create the mcp.json file (global or per project).
Add the server under "mcpServers" as shown and save.
Open Cursor's settings, find the MCP section and check that the server is enabled and lists its tools.
Ask the agent a question the tools can answer and approve the tool call.

Add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "dutyfinch": {
      "url": "https://dutyfinch.cybermaxtools.com/mcp?via=use-with-cursor"
    }
  }
}

With a paid key:

{
  "mcpServers": {
    "dutyfinch": {
      "url": "https://dutyfinch.cybermaxtools.com/mcp?via=use-with-cursor",
      "headers": {
        "x-api-key": "${env:CYBERMAX_API_KEY}"
      }
    }
  }
}

Cursor fills ${env:CYBERMAX_API_KEY} from your environment, so the key never sits in the file.

Where it goes:

~/.cursor/mcp.json (every project)
.cursor/mcp.json (this project only)

Config format checked 2026-10-09 against Cursor's MCP documentation.

Tools you get

Endpoint checked 2026-10-09: https://dutyfinch.cybermaxtools.com/mcp answered an MCP initialize (protocol 2025-06-18) and tools/list with 4 tools, all marked read-only. No key was used and no tool was called.

Tool	What it does	Required inputs
`lookup_hts_code`	US tariff lookup for one HTS code (4, 6, 8 or 10 digits): description, general/special/column 2 duty rates, Section 301 China list status with the additional rate, exclusions, and the 2026 US–China reduction flag.	`code`
`search_hts`	Find US HTS codes from product words (e.g. "air fryer", "wooden toys") or a code prefix. Returns codes with description, general rate and Section 301 China summary.	`q`
`section301_lists`	All Section 301 China tariff headings (lists 1, 2, 3, 4A, 4B, 2024 increases, exclusions) with rates, dates and code counts.	none
`china_deal_status`	Status of the 2026 US–China tariff reduction list (pending / notice_published / published) and, with code, whether that HTS code is on it.	none

Test the endpoint from a terminal

This lists the tools without a key and without calling any of them:

curl -s https://dutyfinch.cybermaxtools.com/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

If it does not work

Cursor uses the top-level key "mcpServers" (VS Code uses "servers"); a file copied from VS Code will not load.
After editing the file, toggle the server off and on in settings if the tools do not appear.
The free tier has a daily limit (see the pricing line above); a paid key raises it.

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