# Seller Fees Calculator (npm · seller-fees-mcp)

Gumroad, Stripe, PayPal and Etsy seller fees, payouts and break-even prices. Local, no API key.

- Trust score: 62/100 (medium)
- Change this week: 0
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

## Components

- npm · `seller-fees-mcp`: 62/100 (this document), [markdown](https://verifymcp.io/servers/narwhalthepong-seller-fees-mcp/seller-fees-mcp.md), [page](https://verifymcp.io/servers/narwhalthepong-seller-fees-mcp/seller-fees-mcp)

## Channel facts

- Registry: `npm`
- Package: `seller-fees-mcp`
- Version: `1.0.1`
- Transport: `stdio`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-05.

- **Supply Chain Security**: 81/100
  - No malware found by supply-chain analysis.
  - CVE check failed: a known high-severity CVE affects zod 3.25.76, a direct dependency. A fixed version is available.
  - No install/post-install scripts declared.
  - 30 of 93 dependencies flagged as unhealthy.
- **Provenance & Transparency**: 45/100
  - Source repository is publicly reachable at the declared URL.
  - Provenance check failed: no build-provenance attestation is published.
  - Clear OSI-approved license (MIT).
  - Actively maintained (last published 7 days ago).
  - Disclosure check failed: no security disclosure policy was found in the source repository.
- **Schema Quality & AI Usability**: 58/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 910 tokens (~182/item across 5 items; 5 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 0/100
  - Stability not yet verified: not enough scan history yet (needs a 30-day window).
- **Tool Coverage**: 98/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 93% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 5 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

**Unverified: 1 category.** A category scored 0 because we could not verify it: a data source with nothing on this package, evidence we could not reach, or a check we could not run. We only credit what we can confirm.

## Install

### How do I install the Seller Fees Calculator MCP server?

Seller Fees Calculator runs locally as an npm package, launched with npx -y seller-fees-mcp. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add narwhalthepong-seller-fees-mcp -- npx -y seller-fees-mcp
```

### Cursor

```json
{
  "mcpServers": {
    "narwhalthepong-seller-fees-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "seller-fees-mcp"
      ]
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "narwhalthepong-seller-fees-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "seller-fees-mcp"
      ]
    }
  }
}
```

### Codex

```bash
codex mcp add narwhalthepong-seller-fees-mcp -- npx -y seller-fees-mcp
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "narwhalthepong-seller-fees-mcp": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "seller-fees-mcp"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add narwhalthepong-seller-fees-mcp --command npx --arg -y --arg seller-fees-mcp
```

### Hermes

```yaml
mcp_servers:
  narwhalthepong-seller-fees-mcp:
    command: "npx"
    args: ["-y", "seller-fees-mcp"]
```

### Netclaw

```json
{
  "McpServers": {
    "narwhalthepong-seller-fees-mcp": {
      "Transport": "stdio",
      "Command": "npx",
      "Arguments": [
        "-y",
        "seller-fees-mcp"
      ]
    }
  }
}
```

### Vellum

```bash
assistant mcp add narwhalthepong-seller-fees-mcp -t stdio -c npx -a -y seller-fees-mcp
```

### Other

```json
{
  "mcpServers": {
    "narwhalthepong-seller-fees-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "seller-fees-mcp"
      ]
    }
  }
}
```

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-10-28 (score 62, +15)

- [security improvement] Malware scan: unverified → pass

### 2026-10-27 (score 47)

First indexed and scored.

## MCP tools (5)

### `fee` (~284 tokens)

Seller fee for one sale

Fee and net amount for one sale on Gumroad, Stripe, PayPal or Etsy (US sellers, USD). Gumroad direct sales include the 2.9% + $0.30 card processing by default.

Input parameters:

- `amount` (number, required): Sale price in USD (Etsy: item price)
- `discover` (boolean): Gumroad: sale came through Gumroad Discover (flat 30%, processing included)
- `extra_pct` (number): Stripe: extra % for international cards or currency conversion
- `gift_wrap` (number): Etsy: gift wrap charged
- `high_volume` (boolean): Gumroad: 5% + $0.50 tier (paid sales this calendar month reached $20,000)
- `international` (boolean): PayPal: international buyer (+1.50%)
- `offsite_ads` (string): Etsy: Offsite Ads fee (std 15%, low 12%)
- `platform` (string, required)
- `processing` (string): Gumroad direct: add card processing 2.9% + $0.30 (default card)
- `qty` (integer): Etsy: items in the order
- `sales_tax_pct` (number): Etsy: sales tax % on the order
- `shipping` (number): Etsy: shipping charged to the buyer
- `type` (string): PayPal payment type (default checkout)

### `payout` (~268 tokens)

Payout after fees

What you keep per sale and in total for a number of units, after platform and processing fees.

Input parameters:

- `amount` (number, required): Sale price in USD
- `discover` (boolean): Gumroad: sale came through Gumroad Discover (flat 30%, processing included)
- `extra_pct` (number): Stripe: extra % for international cards or currency conversion
- `gift_wrap` (number): Etsy: gift wrap charged
- `high_volume` (boolean): Gumroad: 5% + $0.50 tier (paid sales this calendar month reached $20,000)
- `international` (boolean): PayPal: international buyer (+1.50%)
- `offsite_ads` (string): Etsy: Offsite Ads fee (std 15%, low 12%)
- `platform` (string, required)
- `processing` (string): Gumroad direct: add card processing 2.9% + $0.30 (default card)
- `qty` (integer): Etsy: items in the order
- `sales_tax_pct` (number): Etsy: sales tax % on the order
- `shipping` (number): Etsy: shipping charged to the buyer
- `type` (string): PayPal payment type (default checkout)
- `units` (integer): Number of sales (default 1)

### `price_for_target` (~288 tokens)

Price for a target payout

Lowest price (rounded up to the cent) that leaves at least the target amount after fees.

Input parameters:

- `cost_per_item` (number): Etsy: your cost per item
- `discover` (boolean): Gumroad: sale came through Gumroad Discover (flat 30%, processing included)
- `extra_pct` (number): Stripe: extra % for international cards or currency conversion
- `gift_wrap` (number): Etsy: gift wrap charged
- `high_volume` (boolean): Gumroad: 5% + $0.50 tier (paid sales this calendar month reached $20,000)
- `international` (boolean): PayPal: international buyer (+1.50%)
- `label_cost` (number): Etsy: shipping label cost
- `offsite_ads` (string): Etsy: Offsite Ads fee (std 15%, low 12%)
- `platform` (string, required)
- `processing` (string): Gumroad direct: add card processing 2.9% + $0.30 (default card)
- `qty` (integer): Etsy: items in the order
- `sales_tax_pct` (number): Etsy: sales tax % on the order
- `shipping` (number): Etsy: shipping charged to the buyer
- `target` (number, required): Amount you want to keep per sale, USD
- `type` (string): PayPal payment type (default checkout)

### `compare` (~51 tokens)

Compare platforms

Fee and net for one price across Gumroad direct, Gumroad Discover, Stripe, PayPal (checkout, card, goods) and Etsy, best net first.

Input parameters:

- `amount` (number, required): Sale price in USD

### `platforms` (~19 tokens)

Rates and sources

Default rates, options and official source pages for each platform.

## Diagnostics

Captured diagnostic sections: Provenance, Vulnerabilities, Dependencies. The full working is on the page: https://verifymcp.io/servers/narwhalthepong-seller-fees-mcp/seller-fees-mcp#diagnostics

## Score history

- 2026-11-05: 62
- 2026-11-04: 62
- 2026-11-03: 62
- 2026-11-02: 62
- 2026-11-01: 62
- 2026-10-31: 62
- 2026-10-30: 62
- 2026-10-29: 62
- 2026-10-28: 62
- 2026-10-27: 47

## Common questions

### What is the Seller Fees Calculator MCP server?

Seller Fees Calculator is an MCP server listed in the public MCP registry as io.github.NarwhalThePong/seller-fees-mcp. Gumroad, Stripe, PayPal and Etsy seller fees, payouts and break-even prices. Local, no API key. This page covers its npm package (seller-fees-mcp).

### Is the Seller Fees Calculator MCP server safe to use?

Seller Fees Calculator scores 62 out of 100 on VerifyMCP. We recorded 1 known advisory against it as of 5 November 2026. It declares no install or post-install scripts. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the Seller Fees Calculator MCP server expose?

Seller Fees Calculator exposes 5 tools: fee, payout, price_for_target, compare, platforms. Their descriptions and schemas cost roughly 910 tokens of context every time the server is loaded.

### Is the Seller Fees Calculator MCP server still maintained?

Seller Fees Calculator is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What licence is the Seller Fees Calculator MCP server under?

Seller Fees Calculator declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.

## Links

- npm package: https://www.npmjs.com/package/seller-fees-mcp
- Socket report: https://socket.dev/npm/package/seller-fees-mcp
- Repository: https://github.com/NarwhalThePong/seller-fees-mcp
- Changelog RSS feed: https://verifymcp.io/servers/narwhalthepong-seller-fees-mcp/seller-fees-mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/narwhalthepong-seller-fees-mcp/seller-fees-mcp.json
- HTML version of this page: https://verifymcp.io/servers/narwhalthepong-seller-fees-mcp/seller-fees-mcp