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

MCP server · Other

postalref

USPS package barcodes, service type codes and mailing terms, each cited to its USPS source.

Checks passed
13 / 22

1 failed · 8 not measured

Median response
2330 ms

Median of successful probes over 7 days

30-day uptime
Not measured

Share of countable probes over 30 days, including daily rollups. Auth challenges are excluded.

Discovered tools
8

Tool definitions returned by this server

Independent monitoring

Health & checks

Status history

Responded

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

Last checked
Check summary by test group
Test areaPassedFailedUnmeasured
ConnectionCan a client connect and discover tools?
500
Reliability & speedDoes it respond consistently and quickly?
004
Access & authenticationWhat is required to use this server?
102
Tool qualityAre the tool definitions usable by an agent?
400
Publisher identityCan the publisher be traced to its source?
312

Unmeasured means there is not enough evidence to decide. How these checks work

Inspect individual checks 22 recorded

Core

  • Pass
    Reachable

    Latest probe returned HTTP 200 in 2330 ms.

  • Pass
    Valid handshake

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

  • Pass
    Lists tools

    tools/list returned 8 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 2330 ms over 1 samples in 7 days. The bar is 1000 ms. Need at least 5 samples.

  • Not measured
    Consistent (p95)

    95th percentile 2330 ms over 1 samples in 7 days. The bar is 3000 ms. Need at least 20 samples.

  • Not measured
    Reliable (uptime)

    1 of 1 attempts returned a tool list in 30 days (100%). The bar is 99%. Need at least 30 samples.

  • Not measured
    Stable tool list

    Fewer than two successful probes in 30 days, so tool-list stability is not measured.

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.

  • Pass
    Parameters documented

    24 of 24 parameters have a description (100%). The bar is 80%.

  • Pass
    Safety hints

    Every tool sets readOnlyHint or destructiveHint.

Publisher

  • Pass
    Verified namespace

    Listed in the Official MCP Registry.

  • Pass
    Website matches publisher

    The website host matches the reverse-domain namespace.

  • Fail
    Source repo linked

    No repository URL is on file.

  • Not measured
    Repo owner matches

    This namespace is not an io.github login, so the owner comparison does not apply.

  • Pass
    Recently updated

    Updated 2026-11-08T19:08:07.86642Z, within 180 days.

  • Not measured
    Open-source licence

    No GitHub repository to ask about a licence.

Start using postalref

Connect to this server

Choose your client, copy the configuration, then enable the server in your client’s MCP settings.

Run this command in your terminal, then restart Claude Code.

Claude Code

claude mcp add --transport http postalref https://postalref.com/mcp

Capabilities

Tools 8

decode

Read a package barcode or tracking number (IMpb), or a letter's or flat's Intelligent Mail barcode (IMb) from its digits or bars: its layout, each field's digits and meaning, whether the check digit or the bars' frame check holds, and the service type code's or Service Type ID's row in the USPS list, each with the passage that says so. A field's `meaning` is postalref's words: quote a cite's `lit`, USPS's, with its passage.

Discovered
define

What USPS means by a name or abbreviation: each registry entry it names, in the order search ranks them, with its kind and tier, the USPS words that define it and the page they're on, its other names, postalref's own explanation where it has one, and postalref's page about it. An entry USPS ended says when, what replaced it, and USPS's words that say so; one renamed gives its former names, each with USPS's words. Quote a definition's words as they are, citing its document and page; its `read` names the document and page read_source reads them on, with the sentences around them.

Discovered
diff

What changed in a code table or document between two editions: each code added, removed or changed and each changed section, rated editorial, additive or breaking, with who rated it.

Discovered
lookup

Look up a USPS code: its row as USPS prints it in the newest edition that lists it, the codes its cells name, the editions that list it and its history, each row with its passage id. A code is found without the marks USPS prints around it and in a row USPS prints for several codes: 750 finds *750, 858 finds 858 and the dropped 858**, and 13 finds PTR's row 01 / 13. Two digits are also tried as three: 55 finds PTR's 55, then STC's 055. Cite a row by its passage, revision and page, with its cells' words as printed, and a row's `notes`, the footnotes its marks point to, by their own revision and page.

Discovered
read_source

Read any document postalref holds page by page, as extracted, to quote it: a quote cites the revision's sha256, the PDF page and the words exactly. A text without pages, a web page or a product page, reads in parts, and a quote from one cites no page. Quote whole sentences, word for word, from a page's `text` or a `found` context, which shows the whole sentence around the words, or the lead-in with the list it opens. Read another page `found` lists by its `pdf` number, or a part by its number, as `page`. When the text ends mid-sentence or mid-list, `continued` gives the rest of it from `next`, cited by its own page; when it ends mid-table, or a list goes on past `continued`, read `next`.

Discovered
search

Search the codes, terms, banner texts, specs and documents postalref models, by one index: names and codes whose key is the query's first, then those that start with it, then those with words that start with its words, then codes whose row has its words. A term hit carries its kind (mail-class, extra-service, service, program, system, file, identifier, document, facility, container, role or term) and its tier (core, or reference: only in Publication 32, the glossary of July 2013, with that date). A query of 20 or more digits, or an Intelligent Mail barcode's 65 bars as A, D, F and T, comes back as one to decode. A term hit's slug goes to define, and a code's to lookup with its table.

Discovered
search_documents

Search every document on PostalPro by title and file name, with its page and newest file, and the product pages and downloads postalref holds by title. Each one postalref holds the text of carries an `id`, which read_source takes as `document`. A title says only that USPS publishes a document: read one it lists with read_source to learn what it says.

Discovered
search_text

Search the text of every document postalref holds, or of one, for the pages that say the words, best first: those that say them as a phrase, then by how much of the page they are and how many of them it says side by side or close together, a table of contents last. A court's filing or a Justice Department release about a fraud case comes after USPS's own pages when one of those says every word, as Publication 52 and a release about a bulk mail fraud both say bulk mail permit; a case's name finds its records first. A document gives at most three pages while other documents' pages fill the list, and `more` gives each document a hit is from that has more pages with the words, and how many: search again with its id as `document` to rank only its pages. A page needn't have the words a question asks with, such as how, get or take. Each word is found in its forms, and a name also as the registry's other names for it, BCG for Business Customer Gateway or Post Office Box for PO Box, and a size as 4x6 or 4 x 6; a hit another wording found gives it as `by`. Each hit gives the id and page read_source reads, and the passage that says most of the words. Use it when no title names what you're looking for, as for a price in the Mail Classification Schedule or a rule in a DMM chapter. A hit's `context` is a whole sentence, list or row of the page unless it starts or ends with …: quote it with the hit's `id` and `page`, or give them to read_source as `document` and `page` for the sentences around it. When no hit answers, search again with the words an answer would say.

Discovered

Recent measurements

Probe history

View status
Latest stored probes. Raw probe rows are kept for 14 days.
CheckedResultResponseTools
Connected2330 ms8