# contix herramientas (remote · api.contix.es)

Free no-auth tools for Spain: validate IBAN, EU VAT check (VIES), Modelo 303 sums, Veri*factu dates.

- Trust score: 71/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-10-03

## Components

- remote · `api.contix.es`: 71/100 (this document), [markdown](https://verifymcp.io/servers/es-contix-herramientas/api-v1-mcp-herramientas.md), [page](https://verifymcp.io/servers/es-contix-herramientas/api-v1-mcp-herramientas)

## Channel facts

- Endpoint: `https://api.contix.es/api/v1/mcp/herramientas`
- 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 2026-10-03.

- **Endpoint Security**: 80/100
  - 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 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**: 70/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 692 tokens (~173/item across 4 items; 4 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 7/100
  - Stability observed for 2 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 4 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**: 40/100
  - Spec-recency check failed: implements MCP spec 2025-03-26; the latest is 2026-07-28.

## Install

### How do I install the contix herramientas MCP server?

contix herramientas is a hosted endpoint at https://api.contix.es/api/v1/mcp/herramientas, 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 es-contix-herramientas 'https://api.contix.es/api/v1/mcp/herramientas'
```

### Cursor

```json
{
  "mcpServers": {
    "es-contix-herramientas": {
      "url": "https://api.contix.es/api/v1/mcp/herramientas"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "es-contix-herramientas": {
      "type": "http",
      "url": "https://api.contix.es/api/v1/mcp/herramientas"
    }
  }
}
```

### Codex

```toml
[mcp_servers.es-contix-herramientas]
url = "https://api.contix.es/api/v1/mcp/herramientas"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "es-contix-herramientas": {
      "type": "remote",
      "url": "https://api.contix.es/api/v1/mcp/herramientas",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add es-contix-herramientas --url 'https://api.contix.es/api/v1/mcp/herramientas' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  es-contix-herramientas:
    url: "https://api.contix.es/api/v1/mcp/herramientas"
```

### Netclaw

```json
{
  "McpServers": {
    "es-contix-herramientas": {
      "Transport": "http",
      "Url": "https://api.contix.es/api/v1/mcp/herramientas"
    }
  }
}
```

### Vellum

```bash
assistant mcp add es-contix-herramientas -t streamable-http -u 'https://api.contix.es/api/v1/mcp/herramientas'
```

### Other

```json
{
  "mcpServers": {
    "es-contix-herramientas": {
      "type": "http",
      "url": "https://api.contix.es/api/v1/mcp/herramientas"
    }
  }
}
```

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.

### 2026-10-02 (score 71, +1)

- [functional improvement] Stability: unverified → 0.03

### 2026-10-01 (score 70)

First indexed and scored.

## MCP tools (4)

### `validate_iban` (~118 tokens)

Validate an IBAN

Check whether an IBAN is well formed: country length (SWIFT IBAN registry) and ISO 13616 check digits. For Spanish IBANs also the two account check digits (DC) and the bank (entidad) with its BIC from the Banco de España registry. A 20-digit Spanish account number (CCC) is converted to its IBAN. Pure arithmetic: it does NOT confirm that the account exists or who owns it.

Input parameters:

- `iban` (string, required): IBAN or 20-digit Spanish account, spaces allowed

### `check_vat_number` (~116 tokens)

Check an EU VAT number (VIES)

Look up an EU VAT number in the European Commission's VIES registry. Returns what the registry says: whether the number exists and, where the member state publishes it, the name and address. It draws NO tax conclusion. VIES is often down; that is reported as disponible=false, which is NOT the same as an invalid number.

Input parameters:

- `numero` (string, required): VAT number, with or without country prefix
- `pais` (string): ISO country code (e.g. DE); omit when the number carries its prefix

### `calculate_modelo_303` (~236 tokens)

Sum the Spanish VAT return (Modelo 303)

Add up the boxes (casillas) of the Spanish quarterly VAT return Modelo 303 with the formulas printed on the official AEAT form: 27, 45, 46, 64, 66, 87, 69 and 71. Input are the tax amounts (cuotas) per box, e.g. {"09": 17430, "29": 9870}. It only sums what it is given: it does not decide which rate or deduction applies and it is not a tax return.

Input parameters:

- `casillas` (object, required): Box number -> amount. Accepted: 152, 167, 03, 155, 06, 09, 11, 13, 15, 158, 170, 18, 21, 24, 26, 29, 31, 33, 35, 37, 39, 41, 42, 43, 44, 58, 76, 65, 77, 110, 78, 68, 108, 70, 109

### `get_obligation_dates` (~143 tokens)

Veri*factu and e-invoicing deadlines (Spain)

Deadlines from the published Spanish rules: Veri*factu (RD 1007/2023, dates of RD-ley 15/2025) and mandatory B2B e-invoicing (RD 238/2026, counted from the ministerial order, provisional while the order is a draft). Information about the rules, not advice.

Input parameters:

- `factura_a_empresas` (boolean, required): Invoices other businesses or professionals in Spain
- `forma` (string, required): sociedad = company paying Impuesto sobre Sociedades; autonomo = self-employed
- `mas_8_millones` (boolean): Turnover above 8 million EUR last year

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/es-contix-herramientas/api-v1-mcp-herramientas#diagnostics

## Score history

- 2026-10-03: 71
- 2026-10-02: 71
- 2026-10-01: 70

## Common questions

### What is the contix herramientas MCP server?

contix herramientas is an MCP server listed in the public MCP registry as es.contix/herramientas. Free no-auth tools for Spain: validate IBAN, EU VAT check (VIES), Modelo 303 sums, Veri*factu dates. This page covers its hosted endpoint (https://api.contix.es/api/v1/mcp/herramientas).

### Is the contix herramientas MCP server safe to use?

contix herramientas scores 71 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 contix herramientas MCP server expose?

contix herramientas exposes 4 tools: validate_iban, check_vat_number, calculate_modelo_303, get_obligation_dates. Their descriptions and schemas cost roughly 613 tokens of context every time the server is loaded.

### Does the contix herramientas MCP server require authentication?

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

### Is the contix herramientas MCP server still maintained?

contix herramientas is still listed as active in the MCP registry. We last reached this channel on 3 October 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://api.contix.es/api/v1/mcp/herramientas
- Website: https://contix.es/herramientas/
- Changelog RSS feed: https://verifymcp.io/servers/es-contix-herramientas/api-v1-mcp-herramientas.xml
- Changelog JSON feed: https://verifymcp.io/servers/es-contix-herramientas/api-v1-mcp-herramientas.json
- HTML version of this page: https://verifymcp.io/servers/es-contix-herramientas/api-v1-mcp-herramientas