# Stackin

> Issue and manage Brazilian fiscal documents: NF-e for goods, NFS-e for services.

- name: io.github.stackin-io/stackin
- version: 1.0.0
- connection class: R0 (autonomous)
- trust: 94/100
- quality: 85/100 (good)
- owner: not claimed
- descriptor: https://api.protogrid.dev/v1/servers/io.github.stackin-io%2Fstackin
- tools: https://api.protogrid.dev/v1/servers/io.github.stackin-io%2Fstackin/tools

**An agent can connect right now, no human step.** Remote endpoint, no authentication, reachable on the last probe.

## Connection (mcpServers)

```json
{
  "mcpServers": {
    "stackin": {
      "type": "http",
      "url": "https://mcp.stackin.io/mcp"
    }
  }
}
```


## Trust

- hygiene: 100
- liveness: 100
- freshness: 85
- provenance: 90
- drivers: +repository +namespace-matches-repo +website +reachable +uptime-100% ~updated-40d-ago
- Derived from observable signals (official registry feed and our own credential-free probes); no code audit performed.

## Quality 85/100 (good)

### protocol: 75 (weight 25)

- warn `protocol.modern`: newest supported version is 2025-11-25; 2026-07-28 not supported, older versions are deprecated until 2027-07-28
- n/a `protocol.stateless`: only applies to 2026-07-28 servers
- pass `protocol.transport`: streamable HTTP
- n/a `protocol.list_ttl`: only applies to 2026-07-28 servers

### authorization: n/a (weight 15)

- n/a `auth.prm`, `auth.as_metadata`, `auth.cimd`: no remote uses OAuth
- n/a `auth.secret_in_url`: no templated URL

### tool hygiene: 86 (weight 30)

- pass `tools.descriptions`: every tool has a description
- warn `tools.description_length`: 1 tools have descriptions over 1,024 characters, which crowds the context
- pass `tools.schemas`: every tool has an object input schema
- pass `tools.annotations`: 16 of 16 tools declare readOnlyHint or destructiveHint
- pass `tools.directory_hints`: every tool declares readOnlyHint, destructiveHint, idempotentHint and openWorldHint
- warn `tools.token_cost`: about 13,898 tokens to load every tool
- pass `tools.api_dump`: tools are not a one-to-one API dump

### stability: 100 (weight 15)

- pass `stability.changes`: no tool changes in 30 days
- pass `stability.rug_pull`: no tool changed its meaning under the same name

### dependencies: n/a (weight 15)

- n/a `deps.known_vulns`, `deps.mcp_sdk_version`, `deps.resolvable`: no npm or PyPI package

- tools: 16, about 13,898 tokens to load them all
- tool set hash: 1f40baede30c385498cc5b0519d322d2
- badge: [![protogrid quality](https://protogrid.dev/badge/io.github.stackin-io/stackin.svg)](https://protogrid.dev/servers/io.github.stackin-io/stackin)
- Checks run on what our credential-free, read-only probes observe; tools are never called and no code audit is performed.

### Tool changes

_No tool definition changes recorded._

## Remotes

- https://mcp.stackin.io/mcp (streamable-http, auth none, reachable true, uptime30d 1)

## Packages

_none_

## Tools (16)

- `cancel_invoice`: Cancel an authorized invoice.

Legal cancellation, with fiscal and accounting effect, inside a window
the NFS-e authorizer enforces for the municipality. Ask the human to confirm before calling; never call it
speculatively. The reason reaches the tax authority verbatim and must
be at least 15 characters.

Pass idempotency_key to make a retry safe: repeating the same key with
the same access key and reason replays the first answer instead of
cancelling a second time. Reuse the key only when retrying that exact
call; a genuinely new cancellation needs a new key, or none. Nothing
generates one for you — two calls without a key are two cancellations.

- `consult_invoice`: Look up an invoice's current status by its access key.

Read-only: it never changes the document.

- `correct_invoice`: File an electronic correction letter (CC-e) against an NF-e.

NF-e only: there is no correction letter for an NFS-e, where a wrong
document is cancelled and issued again.

It corrects wording and non-fiscal fields only. It cannot change
values, taxes, the recipient or the products — those still require
cancelling and issuing again, and telling the user a CC-e will fix
an amount is wrong in a way they only discover at an audit.

Each letter supersedes the previous one and the SEFAZ keeps at most
20 per document. The text reaches the tax authority verbatim.

- `get_invoice_pdf`: Return the printable rendering of a document, as a PDF.

Works for both types — a DANFE for nfe, a DANFSe for nfse. The PDF
comes back base64-encoded in content_base64; the XML, not this, is
the legally valid document. A 502 from here means the authorizer is
unavailable, not that the invoice is wrong.

- `get_invoice_submissions`: Show every attempt made for one invoice and what came back.

This is the tool that answers "why was it rejected". consult_invoice
gives the status; this gives the tax authority's own code, its
message, and the request and response exactly as they went over the
wire. Read-only.

It takes the invoice_id, like reissue_invoice — a rejected document
has no access key to look it up by. Get the id from list_invoices.

The rows are attempts, not documents: a reissued invoice has more
than one, oldest first, and only the last describes the current
state. Quote the authority's message rather than paraphrasing it;
the code is what the user will search for.

- `invalidate_numbering`: Declare an NF-e numbering range reserved but never used.

NF-e numbering has to be continuous, so a gap left by a failed
issuance is explained to the SEFAZ with this — not with a new
document. Irreversible: a number declared unused can never be used.

Only for numbers that were never authorized. An authorized document
is cancelled, never invalidated. Confirm the range with the user and
read it back before calling: the range is inclusive, and one digit
wrong burns numbers the company still needs.

The SDK refuses a backwards range and a reason outside 15-255
characters before anything is transmitted.

- `issue_invoice`: Issue a Brazilian fiscal document: NFS-e or NF-e.

This produces a legal fiscal document. Confirm the data with the
user before calling when you inferred any field.

Every item needs a price: unit_price is what one unit costs and
amount is the line's gross total. Send unit_price with quantity
when the user quotes a price per unit, amount when they quote the
line. Sending both asserts they agree and is refused if they do
not.

document_type nfse is a service invoice: each item needs a
description and a price, the recipient address is optional, and
service_code (LC 116/2003 item.subitem) falls back to the
company's fiscal profile when omitted.

document_type nfe is for goods, and the SEFAZ rejects a partial
one: every item needs ncm and cfop, and recipient_address is
required with street, number, neighborhood, city, state, zip_code
and city_code all filled. Call validate_invoice_payload first when
any of that was inferred rather than given.

Pass idempotency_key when a retry is possible: repeating the same
key with the same payload replays the first answer instead of
issuing a second document. Without one, a retry after a lost
response issues again — another credit, another number burned,
and undoing it means cancelling, which has a deadline. Nothing
generates the key for you; use one per business event, not per
call.

- `list_fiscal_kinds`: Which classifications this country has data for, right now.

Ask this before assuming a classification exists. The answer
grows as the source data does, so a name absent here is absent
today rather than absent forever.

- `list_invoices`: List the invoices this company issued, newest first.

One document type at a time: pass nfse for services or nfe for
goods. A company that issues both has to be asked twice.

Use it for "my last invoices", "what was rejected today", and to find
a document whose access key the user does not have at hand. Read-only.

An authorized document is stored as issued, which is the value the
rows carry; authorized is accepted as a synonym and asks for the
same thing.

Every row carries both identifiers the other tools need: id, which
reissue_invoice takes, and access_key, which consult_invoice,
cancel_invoice and get_invoice_pdf take. A rejected
row has an id and no access key — the authorizer never assigned one.

- `list_received_invoices`: List NF-e documents other companies issued against this one.

The mirror of list_invoices: that one shows what this company issued,
this one what it received. Read-only.

It reads what the API already collected and never calls the tax
authority, which caps how often a company may ask per day. Each row
carries the issuer, the amount and, once one was filed, the
manifestation. Before a manifestation the authority sends a summary
only; the full document arrives after one.

- `lookup_fiscal_code`: Resolve one code of one classification, when you know both.

Use this to confirm a code before putting it on a document —
an NCM that does not exist is rejected by the tax authority
after issuing, which costs a cancellation.

A code that is not there answers 404. That means the code is
wrong, not that the lookup failed; do not retry it.

`metadata` differs per kind and is passed through as published:
utrib on an NCM, ncm_code on a CEST, tax_type on a CST, and
nothing at all on an ISS service.

- `lookup_taxpayer`: Look up one taxpayer by exact tax id, to confirm who it is.

Use it to check a recipient's name before issuing against them.
It takes the id exactly — punctuation is fine, but there is no
search by name, by prefix or by state, and there will not be:
the registry holds the names and addresses of real people.

A 404 does not mean the company does not exist. The registry
reloads monthly from the RFB's dump, so a recently registered
CNPJ is simply not in it yet. Say that to the user rather than
reporting the tax id as invalid, and never turn a 404 here into
a validation rule.

- `manifest_received_invoice`: Declare this company's position on a document issued against it.

Legally binding and irreversible once the tax authority accepts it —
ask the human to confirm before calling, and read back which
document and which of the four positions is being filed.

Denying a document (210220) or declaring the operation did not
happen (210240) is an accusation against whoever issued it. Never
pick either because the user sounds unsure — ask.

210200 confirms the operation happened, 210210 acknowledges the
document exists, 210220 denies knowing it, and 210240 states the
operation was not carried out. Only 210240 takes a reason, and it
requires one; the others are refused if a reason is sent.

- `reissue_invoice`: Retry a rejected invoice after the data that caused the rejection
was fixed.

Takes the local invoice_id, not the access key: a rejected document
never got one. Consumes a credit like a new issuance, so it takes
an idempotency_key for the same reason issue_invoice does. An
authorized invoice is corrected or cancelled, never reissued.

- `search_fiscal_codes`: Find a code from a description, or page through a table.

This is the tool for "what NCM is a keyboard" — the one the
user actually asks. Prefer it over guessing a code from memory:
the tables change, and a plausible wrong code is worse than a
lookup.

Leaving `kind` unset searches every classification of that
country at once, which is the most expensive call here. Set it
whenever the question already names one.

Rows come back ordered by kind then code; there is no sort
argument, and asking for one changes nothing.

- `validate_invoice_payload`: Check invoice data against the field rules without issuing anything.

Nothing is sent to the tax authority and no document is created.
The SDK models check field formats, and for nfe the rules the SEFAZ
refuses a document over: ncm and cfop on every item, and a complete
recipient address. Worth calling before issue_invoice whenever a
field was inferred rather than given.

This does not replace issuing: the authorizer's cross-field and
fiscal rules are only checked when the document is transmitted.