MCP server · CyberMax

Dutyfinch MCP server

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

Free: 50 free calls a dayPaid: Keys $19/mo

Connect

Streamable HTTP endpoint: https://dutyfinch.cybermaxtools.com/mcp (the original https://dutyfinch.cybermax-tools.workers.dev/mcp keeps working). Add it to Claude Desktop, Cursor, Windsurf or VS Code:

{
  "mcpServers": {
    "dutyfinch": {
      "type": "http",
      "url": "https://dutyfinch.cybermaxtools.com/mcp"
    }
  }
}

No key needed for the free tier. For more calls, add your paid key as the x-api-key header. Full API docs: https://dutyfinch.cybermaxtools.com/docs · Product page: Dutyfinch

Tools

Tool	What it does	Effect	Inputs (* required)
`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.	read-only, calls public sources on the internet, never destructive	`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.	read-only, calls public sources on the internet, never destructive	`q`*, `limit`
`section301_lists`	All Section 301 China tariff headings (lists 1, 2, 3, 4A, 4B, 2024 increases, exclusions) with rates, dates and code counts.	read-only, calls public sources on the internet, never destructive	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.	read-only, calls public sources on the internet, never destructive	`code`

Security and data handling

Your tool arguments are used only to answer that call. They are not saved to a database, shared, sold or used for training.
To make repeat lookups fast, some servers keep the public answer to a lookup in Cloudflare's edge cache for up to 7 days (most for 1 hour or less). It holds the public result, not who asked.
Free tier: a per-day counter keyed by a SHA-256 hash of your IP address and the date (in a Cloudflare Durable Object). The raw IP is not stored.
Paid key: the key is checked with the payment provider (Stripe; Polar for older keys) and the result is cached for 10 minutes; usage is counted per key per month.
No accounts, cookies or tracking on the MCP endpoint. Errors may appear in Cloudflare's short-lived Worker logs.
Every tool is read-only: it looks up public data and returns it. No tool writes, deletes, sends messages or spends money.

Registry and source

Official MCP Registry: dev.workers.cybermax-tools.cybermax/dutyfinch, version 1.1.0.
Public manifest, tool schemas and security notes (MIT): gitlab.com/CyberMax.tools/agent-tools/mcp/dutyfinch. The hosted service code is not public.
Report a vulnerability: security policy.

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