# Spillmark (remote · spillmark.com)

Free Amazon and Meta ads calculators. No brand data and no key.

- Trust score: 74/100 (medium)
- Change this week: 0
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-06

## Components

- remote · `spillmark.com`: 74/100 (this document), [markdown](https://verifymcp.io/servers/com-spillmark-spillmark/spillmark.md), [page](https://verifymcp.io/servers/com-spillmark-spillmark/spillmark)

## Channel facts

- Endpoint: `https://spillmark.com/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.0`

## 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 2026-11-06.

- **Endpoint Security**: 74/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Nothing on it is marked destructive, but we can't show that an anonymous caller can only read: full credit needs the server to list at least one tool and every tool to be verifiably read-only. We use a best-effort check of tool names and descriptions to tell read-only tools from tools that change things, so some genuinely read-only tools may not get full credit. Names that start with a read verb (get, list, read, search and similar) and accurate readOnlyHint annotations help. Meet that to earn full credit, or require authorisation.
  - HTTPS is enforced; there's no plaintext access path.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 65/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 482 tokens (~160/item across 3 items; 3 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 37/100
  - Stability observed for 11 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **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.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 3 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 4 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 Spillmark MCP server?

Spillmark is a hosted endpoint at https://spillmark.com/mcp, 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-spillmark-spillmark 'https://spillmark.com/mcp'
```

### Cursor

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

### VS Code

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

### Codex

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

### opencode

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

### OpenClaw

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

### Hermes

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

### Netclaw

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

### Vellum

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

### Other

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

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.

### 2026-11-06 (score 74, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-11-04 (score 74, +5)

- [security improvement] HTTPS: unverified → pass

### 2026-11-03 (score 69, +1)

No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-11-02 (score 68, −7)

- [security regression] HTTPS: pass → unverified
- [security regression] HSTS header: pass → fail

### 2026-11-01 (score 75, +1)

No change was recorded against any check on this day. Stability & Change Management went from 17 to 20. That category is still filling its 30-day observation window: 5 days of observed history at the previous scan, 6 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-30 (score 74, +1)

- [security] Tool “list_calculators” rewrote its description, which is the text the model reads

### 2026-10-28 (score 73, +1)

No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-27 (score 72, 0)

- [functional improvement] Stability: unverified → 0.03

## MCP tools (3)

### `list_calculators` (~113 tokens)

List Spillmark's free calculators

Spillmark's free Amazon and Meta ads calculators (holdout test size, brand-size MDE, geo holdout states, ad waste, Meta ROAS reality check, incremental ROAS, break-even ROAS, ACoS, TACoS, Amazon fees and profit, LTV and CAC), with each one's inputs and example values. Use run_calculator to run one.

Input parameters:

- `q` (string): Filter by words in the name or summary, e.g. 'holdout' or 'fees'

### `run_calculator` (~122 tokens)

Run a Spillmark calculator

Runs one calculator from list_calculators on your numbers and returns the headline result, the supporting figures, a one-sentence reading, and a link that opens the calculator with the same inputs. Missing inputs use the calculator's example values. Enter percents as points (15 means 15%), choices as the option index.

Input parameters:

- `currency` (string): Currency for money results. Default USD
- `inputs` (object): Input values by key
- `slug` (string, required): Calculator slug from list_calculators, e.g. holdout-test-calculator

### `how_lift_is_calculated` (~49 tokens)

How Spillmark calculates lift

Spillmark's method in brief: how a geo holdout test measures the sales Meta ads cause on Amazon, with links to the full method and a sample report on made-up numbers.

## Diagnostics

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

## Score history

- 2026-11-06: 74
- 2026-11-05: 74
- 2026-11-04: 74
- 2026-11-03: 69
- 2026-11-02: 68
- 2026-11-01: 75
- 2026-10-31: 74
- 2026-10-30: 74
- 2026-10-29: 73
- 2026-10-28: 73
- 2026-10-27: 72
- 2026-10-26: 72

## Common questions

### What is the Spillmark MCP server?

Spillmark is an MCP server listed in the public MCP registry as com.spillmark/spillmark. Free Amazon and Meta ads calculators. No brand data and no key. This page covers its hosted endpoint (https://spillmark.com/mcp).

### Is the Spillmark MCP server safe to use?

Spillmark scores 74 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 Spillmark MCP server expose?

Spillmark exposes 3 tools: list_calculators, run_calculator, how_lift_is_calculated. Their descriptions and schemas cost roughly 284 tokens of context every time the server is loaded.

### Does the Spillmark MCP server require authentication?

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

### Is the Spillmark MCP server still maintained?

Spillmark is still listed as active in the MCP registry. We last reached this channel on 6 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What did VerifyMCP test on the Spillmark MCP server?

VerifyMCP ran 13 checks on Spillmark, covering TLS certificate, Authorization, HTTPS, HSTS header and 9 more. Supply Chain Security and Provenance & Transparency do not apply to a hosted endpoint, so they were not tested. The score does not measure everything, and the scoring documentation lists what it leaves out.

## Links

- Remote endpoint: https://spillmark.com/mcp
- Changelog RSS feed: https://verifymcp.io/servers/com-spillmark-spillmark/spillmark.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-spillmark-spillmark/spillmark/changelog.json
- Trust report (JSON): https://verifymcp.io/servers/com-spillmark-spillmark/spillmark.json
- HTML version of this page: https://verifymcp.io/servers/com-spillmark-spillmark/spillmark