Fiscalisto for Hermes Agent
Mexican electronic invoicing (CFDI 4.0) and SAT taxes from your agent. This plugin connects Hermes Agent to Fiscalisto, the Mexican invoicing app that downloads your issued and received CFDI from the SAT every morning, and gives the agent the same features as the web app.
Ask things like:
- «Factúrale a Comercializadora Delta 3 horas de consultoría a $1,500 más IVA»
- "How much VAT do I owe this month, and is anything wrong before I file?"
- «¿Quién me debe facturas PPD de más de 60 días?»
- "Check my suppliers against the SAT 69-B list"
- «Descarga mi constancia de situación fiscal y mi opinión de cumplimiento»
What it does
- Invoices: search issued and received CFDI, draft and stamp invoices, send them by email, cancel them with the SAT reason, duplicate them, share a public link.
- Getting paid: open PPD balances with aging, payment receipts (REP), credit notes, advances and applying them.
- Taxes: the month's VAT, income, expenses, withholdings and an ISR estimate, findings to fix before filing (69-B suppliers, pending cancellations, cash over $2,000), DIOT, declarations already filed.
- SAT documents: constancia de situación fiscal, opinión de cumplimiento (32-D), buzón tributario notices, SAT downloads.
- Everything else in the app: clients, products, quotes, recurring invoices, payroll receipts, retention certificates, the global invoice for counter sales, purchases, inventory, branches, team and settings.
The plugin bundles an overview skill (fiscalisto:fiscalisto, in English) and thirteen workflow skills in Spanish: facturar, cancelar-factura, cobranza, nota-de-credito, anticipos, cierre-del-mes, revisar-proveedores, documentos-sat, cotizar, facturas-recurrentes, nomina, constancias-retenciones and factura-global.
Install
You need Hermes Agent 0.21.6 or newer, Node.js 20.18.1 or newer with npx on your PATH, and a Fiscalisto account (free sign-up at fiscalisto.com).
From the Hermes plugin catalog:
hermes plugins install fiscalisto
hermes plugins enable fiscalisto
Or straight from GitHub:
hermes plugins install RVP97/fiscalisto-hermes --no-enable
hermes plugins enable fiscalisto
Start a new session. The first time the server starts, your browser opens Fiscalisto's sign-in. Sign in, pick the companies the agent may use and what it may do (read, prepare drafts, stamp), and approve. The token is kept and refreshed, so you sign in once. If the tools don't show up after you sign in, run /reload-mcp. You can revoke the connection any time in Fiscalisto under Ajustes › Seguridad › Apps conectadas.
Without Node.js
Hermes's own MCP client can sign in to Fiscalisto too. Skip the plugin and add this to ~/.hermes/config.yaml:
mcp_servers:
fiscalisto:
url: "https://fiscalisto.com/mcp"
auth: oauth
trust: untrusted
Before you install
The package is plugin.json, mcp.json and the skills in skills/. It ships no code of its own.
mcp.jsonruns the pinnedmcp-remote@0.1.49throughnpx, which downloads it from npm on first use. It opens a local callback port for the sign-in and stores the OAuth tokens in~/.mcp-auth.- Every tool call goes to
fiscalisto.comand acts on the companies you approved, with your own role in each. The server decides the tool set at runtime, so the pinned commit doesn't cover it. plugin.jsonmarks the serveruntrusted. Hermes asks before every tool the server doesn't mark read-only (drafting, stamping, cancelling and emailing invoices, payroll, changing settings) and refuses those tools in cron and other unattended runs.- Stamping an invoice registers it with the SAT through Fiscalisto's PAC and uses one of your plan's stamps (timbres). Stamping and cancelling also need a confirmation token from a preview the agent showed you, so the server refuses a stamp that wasn't previewed.
- The package sends no telemetry.
Links
- Fiscalisto: fiscalisto.com
- Fiscalisto in ChatGPT and Claude: fiscalisto.com/apps/chatgpt-y-claude
- Fiscalisto API docs: fiscalisto.com/docs/api
- Privacy: fiscalisto.com/privacidad
License
MIT
README from the reviewed commit f605ade; it updates when the author re-pins.

Fiscalisto