# Mexican Payroll & Tax Calculator (remote · fiscal.tinyapis.dev)

Deterministic Mexican payroll & tax math: finiquito, ISR, aguinaldo, IMSS (2026 tables).

- Trust score: 67/100 (medium)
- Change this week: +4
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

- remote · `fiscal.tinyapis.dev`: 67/100 (this document), [markdown](https://verifymcp.io/servers/dev-tinyapis-mx-fiscal/fiscal.md), [page](https://verifymcp.io/servers/dev-tinyapis-mx-fiscal/fiscal)

## Channel facts

- Endpoint: `https://fiscal.tinyapis.dev/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 2026-08-03.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 4 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - 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**: 65/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 879 tokens (~219/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**: 27/100
  - Stability observed for 8 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.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### Claude

```bash
claude mcp add --transport http dev-tinyapis-mx-fiscal https://fiscal.tinyapis.dev/mcp
```

### Codex

```toml
[mcp_servers.dev-tinyapis-mx-fiscal]
url = "https://fiscal.tinyapis.dev/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "dev-tinyapis-mx-fiscal": {
      "type": "remote",
      "url": "https://fiscal.tinyapis.dev/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add dev-tinyapis-mx-fiscal --url https://fiscal.tinyapis.dev/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  dev-tinyapis-mx-fiscal:
    url: "https://fiscal.tinyapis.dev/mcp"
```

### Other

```json
{
  "mcpServers": {
    "dev-tinyapis-mx-fiscal": {
      "type": "http",
      "url": "https://fiscal.tinyapis.dev/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.

### 2026-08-02 (score 67, +1)

No change was recorded against any check on this day. Stability & Change Management went from 20 to 23. That category is still filling its 30-day observation window: 6 days of observed history at the previous scan, 7 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-31 (score 66, +1)

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

### 2026-07-30 (score 65, +1)

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

### 2026-07-29 (score 64, +1)

No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-27 (score 63, +1)

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

### 2026-07-26 (score 62)

First indexed and scored.

## MCP tools (4)

### `calc_finiquito` (~323 tokens)

Compute a Mexican finiquito/liquidación (severance) for a resignation or
an unjustified dismissal: prorated christmas bonus, vacations, vacation
premium, pending salary, and (for dismissal) 90-day + 20-day/year
severance and the seniority premium, with Art. 93 exemptions and
separation ISR. Do NOT compute this from memory — LFT bands, UMA
exemptions, and the SDI integration factor are table-driven. Returns
per-concept gross/exempt/taxable, totals, ISR, deductions, and net_total.

Input parameters:

- `daily_salary` (number, required): Daily salary (MXN).
- `deductions` (array): Optional pass-through deductions.
- `hire_date` (string, required): Hire date, YYYY-MM-DD.
- `include_20_days_per_year` (boolean): Include the 20-day/year dismissal indemnity.
- `monthly_ordinary_salary` (number): Monthly ordinary salary for ISR (defaults to daily x 30.4).
- `paid_in_january` (boolean): January UMA boundary.
- `pending_days` (integer): Unpaid worked days pending.
- `prima_vacacional_pct` (number): Vacation premium percentage (defaults to the legal 25%).
- `termination_date` (string, required): Termination date, YYYY-MM-DD.
- `termination_type` (string, required): Type of separation.
- `vacation_proration` (string): Vacation proration basis.
- `year` (integer): Tax-table year.
- `zone` (string): Minimum-wage zone.

### `calc_isr` (~130 tokens)

Compute Mexican ISR (income tax) withholding for a monthly or annual
income using the official SAT tables and employment subsidy. Do NOT
estimate ISR from memory — brackets and subsidy change yearly and must
come from this deterministic tool. Returns tax, subsidy_applied,
withholding, the period, and the tax-table year used.

Input parameters:

- `income` (number, required): Gross income for the period (MXN).
- `paid_in_january` (boolean): January UMA boundary (2025 vs 2026 tables).
- `period` (string): Tax period.
- `year` (integer): Tax-table year.

### `calc_aguinaldo` (~179 tokens)

Compute a Mexican aguinaldo (year-end bonus): gross, the UMA-based
exempt portion, the taxable portion, its ISR, and the net. Minimum 15
days by law. Do NOT compute from memory — the exemption is UMA-indexed
per year. Returns gross, taxable, exempt, isr, net, and the days used.

Input parameters:

- `aguinaldo_days` (integer): Aguinaldo days (defaults to the legal 15).
- `daily_salary` (number, required): Daily salary (MXN).
- `days_worked` (integer, required): Days worked in the year.
- `monthly_ordinary_salary` (number): Monthly ordinary salary for ISR (defaults to daily x 30.4).
- `paid_in_january` (boolean): January UMA boundary.
- `year` (integer): Tax-table year.

### `calc_imss` (~247 tokens)

Compute Mexican IMSS social-security contributions: the SDI (integrated
daily wage by seniority) and SBC, plus employer/worker quotas for the
five insurance branches. The work-risk premium (rt_premium) is an input.
Provide either seniority_years (to derive the SDI) or an explicit sdi.
Do NOT compute from memory — quota tables and UMA caps are table-driven.
Returns sdi, sbc, employer_total, worker_total, grand_total, and a
per-branch breakdown.

Input parameters:

- `daily_salary` (number): Daily salary (MXN); with seniority_years derives the SDI.
- `days` (integer): Number of days to bill.
- `paid_in_january` (boolean): January UMA boundary.
- `rt_premium` (number, required): Work-risk premium (fraction, e.g. 0.005).
- `sdi` (number): Explicit integrated daily wage, if not deriving from salary.
- `seniority_years` (integer): Completed years of seniority (for the SDI integration factor).
- `year` (integer): Tax-table year.
- `zone` (string): Minimum-wage zone.

## Diagnostics

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

## Score history

- 2026-08-03: 67
- 2026-08-02: 67
- 2026-08-01: 66
- 2026-07-31: 66
- 2026-07-30: 65
- 2026-07-29: 64
- 2026-07-28: 63
- 2026-07-27: 63
- 2026-07-26: 62

## Links

- Remote endpoint: https://fiscal.tinyapis.dev/mcp
- Website: https://fiscal.tinyapis.dev/
- Changelog RSS feed: https://verifymcp.io/servers/dev-tinyapis-mx-fiscal/fiscal/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/dev-tinyapis-mx-fiscal/fiscal/changelog.json
- HTML version of this page: https://verifymcp.io/servers/dev-tinyapis-mx-fiscal/fiscal