Use Dutyfinch MCP with Claude Code

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

Run the command in your terminal (add --scope user to use it in every project, or --scope project to write .mcp.json).
Start Claude Code and type /mcp to see the server and its tools.
Ask a question the tools can answer; Claude Code asks permission before each tool call unless you allow it.

Run:

claude mcp add --transport http dutyfinch 'https://dutyfinch.cybermaxtools.com/mcp?via=use-with-claude-code'

Or share it with your team in .mcp.json (project scope)::

{
  "mcpServers": {
    "dutyfinch": {
      "type": "http",
      "url": "https://dutyfinch.cybermaxtools.com/mcp?via=use-with-claude-code"
    }
  }
}

With a paid key:

claude mcp add --transport http dutyfinch 'https://dutyfinch.cybermaxtools.com/mcp?via=use-with-claude-code' \
  --header "x-api-key: YOUR_KEY"

In .mcp.json, ${CYBERMAX_API_KEY} is read from the environment so the key is not committed.

Where it goes:

stored by the CLI: local scope (default, you in this project), project scope (.mcp.json, shared), user scope (you, every project)

Config format checked 2026-10-09 against Claude Code'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

If a project-scoped server does not load, Claude Code asks you to approve servers from .mcp.json the first time.
The free tier has a daily limit (see the pricing line above); a paid key raises it.

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