# Moltline Merchant Maths (remote · mcp.moltlinestudio.com)

Processor fees, charge-to-net, invoice totals and proration. 3 of 6 tools free.

- Trust score: 85/100 (high trust)
- Change this week: +1
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-21

## Components

- remote · `mcp.moltlinestudio.com`: 85/100 (this document), [markdown](https://verifymcp.io/servers/com-moltlinestudio-merchant/merchant.md), [page](https://verifymcp.io/servers/com-moltlinestudio-merchant/merchant)

## Channel facts

- Endpoint: `https://mcp.moltlinestudio.com/merchant`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.2.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, 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 2026-09-21.

- **Endpoint Security**: 83/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC is configured correctly; the domain's records validate against the full chain to the root.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 62/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 1823 tokens (~303/item across 6 items; 6 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 100/100
  - No destabilizing schema changes in the last 30 days.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 75/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - 0 of 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation; "charge_to_net" implies "charge" and declares readOnlyHint instead, contradicting what its own name says it does.
  - An AI judge read all 7 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.

## Install

### How do I install the Moltline Merchant Maths MCP server?

Moltline Merchant Maths is a hosted endpoint at https://mcp.moltlinestudio.com/merchant, so there is nothing to install locally. 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 --transport http com-moltlinestudio-merchant 'https://mcp.moltlinestudio.com/merchant'
```

### Cursor

```json
{
  "mcpServers": {
    "com-moltlinestudio-merchant": {
      "url": "https://mcp.moltlinestudio.com/merchant"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "com-moltlinestudio-merchant": {
      "type": "http",
      "url": "https://mcp.moltlinestudio.com/merchant"
    }
  }
}
```

### Codex

```toml
[mcp_servers.com-moltlinestudio-merchant]
url = "https://mcp.moltlinestudio.com/merchant"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-moltlinestudio-merchant": {
      "type": "remote",
      "url": "https://mcp.moltlinestudio.com/merchant",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-moltlinestudio-merchant --url 'https://mcp.moltlinestudio.com/merchant' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  com-moltlinestudio-merchant:
    url: "https://mcp.moltlinestudio.com/merchant"
```

### Netclaw

```json
{
  "McpServers": {
    "com-moltlinestudio-merchant": {
      "Transport": "http",
      "Url": "https://mcp.moltlinestudio.com/merchant"
    }
  }
}
```

### Vellum

```bash
assistant mcp add com-moltlinestudio-merchant -t streamable-http -u 'https://mcp.moltlinestudio.com/merchant'
```

### Other

```json
{
  "mcpServers": {
    "com-moltlinestudio-merchant": {
      "type": "http",
      "url": "https://mcp.moltlinestudio.com/merchant"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## 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.

### 2026-09-16 (score 85, +1)

- [security] Stability: 0.97 → pass

### 2026-09-14 (score 84, +1)

No change was recorded against any check on this day. Stability & Change Management went from 90 to 93. That category is still filling its 30-day observation window: 27 days of observed history at the previous scan, 28 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-12 (score 83, +1)

No change was recorded against any check on this day. Stability & Change Management went from 83 to 87. That category is still filling its 30-day observation window: 25 days of observed history at the previous scan, 26 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-09 (score 82, +1)

No change was recorded against any check on this day. Stability & Change Management went from 73 to 77. That category is still filling its 30-day observation window: 22 days of observed history at the previous scan, 23 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-07 (score 81, +1)

No change was recorded against any check on this day. Stability & Change Management went from 67 to 70. That category is still filling its 30-day observation window: 20 days of observed history at the previous scan, 21 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-05 (score 80, +1)

No change was recorded against any check on this day. Stability & Change Management went from 60 to 63. That category is still filling its 30-day observation window: 18 days of observed history at the previous scan, 19 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-03 (score 79, +1)

No change was recorded against any check on this day. Stability & Change Management went from 53 to 57. That category is still filling its 30-day observation window: 16 days of observed history at the previous scan, 17 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-01 (score 78, +1)

No change was recorded against any check on this day. Stability & Change Management went from 47 to 50. That category is still filling its 30-day observation window: 14 days of observed history at the previous scan, 15 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (6)

### `processor_fees` (~348 tokens)

Processor Fees

Break down payment-processor fees: fee, net, and effective rate. FREE.

Uses editable presets for stripe/paypal/square/shopify (verify current
rates) or your own custom_pct + custom_fixed. Typical input {"amount":
1000, "processor": "stripe", "transactions": 10} returns {"gross":
1000, "fee": 32.0, "net": 968.0, "effective_rate_pct": 3.2, "note":
"..."}.

Use when the charge amount is known and the net payout is the question.
Not for the reverse: the gross needed to net a target is charge_to_net. Errors: on invalid, missing, or malformed input this tool never raises a protocol error — it returns {"error": "<what is wrong and how to fix it>"} (for example {"error": "amount must be > 0, transactions >= 1"}). Every call is read-only and idempotent, so after correcting the input it is always safe to retry.

Input parameters:

- `amount` (number, required): Total gross amount processed; must be greater than 0.
- `custom_fixed` (number): Fixed per-transaction fee used when processor is "custom", e.g. 0.25.
- `custom_pct` (number): Percentage fee used when processor is "custom", e.g. 2.5 for 2.5%.
- `processor` (string): One of "stripe", "paypal", "square", "shopify", or "custom". Default "stripe".
- `transactions` (integer): How many transactions the amount is spread across; at least 1. Default 1.

### `charge_to_net` (~280 tokens)

Charge To Net

Compute the gross price to charge so you net a target after fees. FREE.

'Charge X to receive Y' after percentage + fixed processor fees.
Typical input {"net_target": 100, "pct_fee": 2.9, "fixed_fee": 0.30}
returns {"charge": 103.4, "fee": 3.4, "net": 100.0}.

The inverse of processor_fees - solves for gross from a target net. Use
when the payout is the fixed requirement. Not when the price is already
set. Errors: on invalid, missing, or malformed input this tool never raises a protocol error — it returns {"error": "<what is wrong and how to fix it>"} (for example {"error": "net_target > 0 and pct_fee < 100 required"}). Every call is read-only and idempotent, so after correcting the input it is always safe to retry.

Input parameters:

- `fixed_fee` (number): Processor fixed fee per charge. Default 0.30.
- `net_target` (number, required): The amount you want to receive after fees; must be greater than 0.
- `pct_fee` (number): Processor percentage fee, below 100, e.g. 2.9 for 2.9%. Default 2.9.

### `invoice_total` (~325 tokens)

Invoice Total

Total an invoice: per-line totals, subtotal, discount, tax, grand total. FREE.

Typical input {"line_items": [{"desc": "Design", "qty": 2,
"unit_price": 50}], "tax_pct": 8.5, "discount_pct": 10} returns
{"lines": [{"desc": "Design", "qty": 2, "unit_price": 50,
"line_total": 100.0}], "subtotal": 100.0, "discount": 10.0, "tax":
7.65, "total": 97.65}.

Use when several line items roll up with discount and tax. Not for one
transaction's fees (processor_fees) and not for spreading a total over
time (installment_plan). Errors: on invalid, missing, or malformed input this tool never raises a protocol error — it returns {"error": "<what is wrong and how to fix it>"} (for example {"error": "line_items must contain at least one item,"}). Every call is read-only and idempotent, so after correcting the input it is always safe to retry.

Input parameters:

- `discount_pct` (number): Discount percentage applied to the subtotal. Default 0.
- `line_items` (array, required): At least one line item object {"desc": str, "qty": number, "unit_price": number}; the first 100 items are used.
- `tax_pct` (number): Tax percentage applied after the discount, e.g. 8.5. Default 0.

### `discount_stack` (~268 tokens)

Discount Stack

Stack discounts correctly: sequential vs additive comparison. PREMIUM (license).

The two methods differ — this shows both, the final price, and the true
total discount. Typical input {"price": 200, "discounts_pct": [20, 10]}
returns {"original": 200, "sequential_price": 144.0,
"sequential_total_discount_pct": 28.0, "additive_price": 140.0,
"difference": 4.0, "note": "..."}.

Use when more than one discount applies and the order changes the answer.
Not for a single discount inside an invoice (invoice_total). Errors: on invalid, missing, or malformed input this tool never raises a protocol error — it returns {"error": "<what is wrong and how to fix it>"} (for example {"error": "price > 0 and at least one discount required"}). Every call is read-only and idempotent, so after correcting the input it is always safe to retry.

Input parameters:

- `discounts_pct` (array, required): Discount percentages in the order applied, at least one, e.g. [20, 10] for 20% then 10%.
- `price` (number, required): Original price before discounts; must be greater than 0.

### `proration` (~296 tokens)

Proration

Compute a prorated charge or refund for a partial billing period. PREMIUM (license).

Typical input {"amount_per_period": 90, "days_used": 10,
"days_in_period": 30} returns {"days_used": 10, "days_in_period": 30,
"prorated_charge": 30.0, "prorated_refund": 60.0, "answer": 30.0}.

Use when a plan starts, ends, or changes mid-period. Not for splitting a
full amount into scheduled payments (installment_plan). Errors: on invalid, missing, or malformed input this tool never raises a protocol error — it returns {"error": "<what is wrong and how to fix it>"} (for example {"error": "need amount > 0 and 0 <= days_used <= days_in_period"}). Every call is read-only and idempotent, so after correcting the input it is always safe to retry.

Input parameters:

- `amount_per_period` (number, required): Full-period price; must be greater than 0.
- `days_in_period` (integer): Length of the billing period in days; at least 1. Default 30.
- `days_used` (integer, required): Days of the period consumed; 0 to days_in_period.
- `refund_mode` (boolean): If true, "answer" is the refund amount instead of the charge. Default false.

### `installment_plan` (~264 tokens)

Installment Plan

Split a total into an installment schedule with optional deposit. PREMIUM (license).

Rounding remainders land on the final payment so the schedule always
sums exactly. Typical input {"total": 1000, "installments": 3,
"deposit_pct": 10} returns {"deposit": 100.0, "payments": [300.0,
300.0, 300.0], "check_sum": 1000.0}.

Use when one total is paid across scheduled dates. Not for partial-period
adjustments (proration). Errors: on invalid, missing, or malformed input this tool never raises a protocol error — it returns {"error": "<what is wrong and how to fix it>"} (for example {"error": "total > 0 and 1-36 installments"}). Every call is read-only and idempotent, so after correcting the input it is always safe to retry.

Input parameters:

- `deposit_pct` (number): Optional upfront deposit as a percentage of total, e.g. 10 for 10%. Default 0.
- `installments` (integer, required): Number of payments after the deposit; 1 to 36.
- `total` (number, required): Full amount to split; must be greater than 0.

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/com-moltlinestudio-merchant/merchant#diagnostics

## Score history

- 2026-09-21: 85
- 2026-09-20: 85
- 2026-09-19: 85
- 2026-09-18: 85
- 2026-09-17: 85
- 2026-09-16: 85
- 2026-09-15: 84
- 2026-09-14: 84
- 2026-09-13: 83
- 2026-09-12: 83
- 2026-09-11: 82
- 2026-09-10: 82
- 2026-09-09: 82
- 2026-09-08: 81
- 2026-09-07: 81
- 2026-09-06: 80
- 2026-09-05: 80
- 2026-09-04: 79
- 2026-09-03: 79
- 2026-09-02: 78
- 2026-09-01: 78
- 2026-08-31: 77
- 2026-08-30: 77
- 2026-08-29: 76
- 2026-08-28: 76
- 2026-08-27: 75
- 2026-08-26: 75
- 2026-08-25: 75
- 2026-08-24: 74
- 2026-08-23: 74

## Common questions

### What is the Moltline Merchant Maths MCP server?

Moltline Merchant Maths is an MCP server listed in the public MCP registry as com.moltlinestudio/merchant. Processor fees, charge-to-net, invoice totals and proration. 3 of 6 tools free. This page covers its hosted endpoint (https://mcp.moltlinestudio.com/merchant).

### Is the Moltline Merchant Maths MCP server safe to use?

Moltline Merchant Maths scores 85 out of 100 on VerifyMCP. 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 Moltline Merchant Maths MCP server expose?

Moltline Merchant Maths exposes 6 tools: processor_fees, charge_to_net, invoice_total, discount_stack, proration, installment_plan. Their descriptions and schemas cost roughly 1,781 tokens of context every time the server is loaded.

### Does the Moltline Merchant Maths MCP server require authentication?

No. We connected to Moltline Merchant Maths without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the Moltline Merchant Maths MCP server still maintained?

Moltline Merchant Maths is still listed as active in the MCP registry. We last reached this channel on 21 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://mcp.moltlinestudio.com/merchant
- Repository: https://github.com/GarphenGate/moltline-mcp
- Website: https://moltlinestudio.com/servers.html#merchant
- Changelog RSS feed: https://verifymcp.io/servers/com-moltlinestudio-merchant/merchant.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-moltlinestudio-merchant/merchant.json
- HTML version of this page: https://verifymcp.io/servers/com-moltlinestudio-merchant/merchant