MCP HeartbeatTHE MCP OBSERVATORY
Public workspace

Explore

Evidence for your next connection.

Independent measurements of remote MCP servers. Every observation has a timestamp.

Read-only probes

Stackin

Claim this listing

io.github.stackin-io/stackin

stackin-ioVerified

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

Developer ToolsIs Stackin down?Alternatives

14 of 22 checks passed

  • Handshake
  • Tools listed
  • Updated recently

Responded

The server completed its last measured handshake. This is an observation, not a guarantee.

Connect to server
Median latency
2221 ms
Uptime, 30 days
Not measured
Last checked

Measurement details

Core

  • Pass
    Reachable

    Latest probe returned HTTP 200 in 2216 ms.

  • Pass
    Valid handshake

    protocolVersion 2025-11-25, serverInfo.name stackin.

  • Pass
    Lists tools

    tools/list returned 16 tools.

  • Pass
    Current protocol

    Negotiated 2025-11-25. The bar is 2025-06-18 or newer.

  • Pass
    HTTPS

    The endpoint URL is https.

Performance

  • Not measured
    Fast (p50)

    Median latency 2221 ms over 2 samples in 7 days. The bar is 1000 ms. Need at least 5 samples.

  • Not measured
    Consistent (p95)

    95th percentile 2226 ms over 2 samples in 7 days. The bar is 3000 ms. Need at least 20 samples.

  • Not measured
    Reliable (uptime)

    2 of 2 attempts returned a tool list in 30 days (100%). The bar is 99%. Need at least 30 samples.

  • Pass
    Stable tool list

    No tool was removed and no required parameter was added in the last 30 days.

Access

  • Pass
    Open access

    tools/list succeeded with no credential, and the record declares none.

  • Not measured
    Standard auth

    Auth is not required, so the OAuth metadata check does not apply.

  • Not measured
    Free tier cited

    No publisher quote has been checked.

Tools

  • Pass
    Tools described

    Every tool description is at least 20 characters.

  • Pass
    Valid input schemas

    Every inputSchema is a JSON Schema object.

  • Fail
    Parameters documented

    11 of 48 parameters have a description (23%). The bar is 80%.

  • Pass
    Safety hints

    Every tool sets readOnlyHint or destructiveHint.

Publisher

  • Pass
    Verified namespace

    Listed in the Official MCP Registry.

  • Not measured
    Website matches publisher

    This namespace is not a reverse domain, so the website comparison does not apply.

  • Pass
    Source repo linked

    A repository URL is on file.

  • Pass
    Repo owner matches

    The GitHub repository owner matches the namespace login.

  • Pass
    Recently updated

    Updated 2026-09-09T04:48:20.026868Z, within 180 days.

  • Not measured
    Open-source licence

    The GitHub licence lookup has not returned an OSI result yet.

Tools

  • 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.

    Measured

  • consult_invoice

    Look up an invoice's current status by its access key. Read-only: it never changes the document.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

  • 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.

    Measured

Probe history

  • ok2216 ms16 tools
  • ok2226 ms16 tools

Status and uptime

Add badge to your README

The image links back to this page. It shows checks passed, or uptime, and the colour follows the latest status. Responses are cached for 5 to 15 minutes.

MCP Heartbeat badge

Markdown

[![MCP Heartbeat](https://mcpheartbeat.com/badge/io.github.stackin-io/stackin.svg)](https://mcpheartbeat.com/s/io.github.stackin-io/stackin)

HTML

<a href="https://mcpheartbeat.com/s/io.github.stackin-io/stackin"><img alt="MCP Heartbeat" src="https://mcpheartbeat.com/badge/io.github.stackin-io/stackin.svg"></a>

Uptime markdown

[![MCP Heartbeat uptime](https://mcpheartbeat.com/badge/io.github.stackin-io/stackin.svg?kind=uptime)](https://mcpheartbeat.com/s/io.github.stackin-io/stackin)

Served from https://mcpheartbeat.com.

Related servers

All alternatives

Same function and industry, ranked by checks passed then median latency.

Connect to this server

Claude Code

claude mcp add --transport http stackin https://mcp.stackin.io/mcp

Cursor .cursor/mcp.json

{
  "mcpServers": {
    "stackin": {
      "url": "https://mcp.stackin.io/mcp"
    }
  }
}

VS Code .vscode/mcp.json

{
  "servers": {
    "stackin": {
      "type": "http",
      "url": "https://mcp.stackin.io/mcp"
    }
  }
}