io.github.cyanheads/iana-registries-mcp-server

Read records from any IANA XML registry by id, e.g. registry "tls-parameters" with subregistry "tls-parameters-4" (TLS Cipher Suites), "protocol-numbers", "http-methods", or "cbor-tags"; an iana.org/assignments URL also works. Filter with `value` on the key column or the column `field` names: signed decimal points match exact cells, inclusive ranges and strict open bounds; scalar 0x points also compare with decimal cells and established bare-hex columns. Two-byte 0x points match byte-pair ranges and wildcards with their width preserved. An implicit range-only key match yields a miss and a field pointer when another column holds the value exactly. Filter with `contains` for words in any field; records with an equal field come first. When a registry has several sub-registries and none is given, the response lists them instead of records; a table that nests tables lists them too. Field names are the registry's XML element names (e.g. "rec" is the Recommended column). Large registries page through `cursor`. Find ids with iana_search_registries.

Get the current status of up to ten distinct RFCs, Internet-Drafts, or BCP/STD/FYI series per page from up to 1,000 input items. Canonical aliases resolve once. When more remain, deferred_ids previews the next ten, deferred_count counts the whole remainder, and next_ids_offset continues the same original ids. Retry failed ids separately. Accepts "RFC 9110", "rfc9110", "9110", draft names with or without a revision suffix ("draft-ietf-httpbis-semantics-19"), series numbers ("BCP 14"), RFC and draft file names ("rfc9110.txt"), the URL of an RFC or draft on datatracker.ietf.org, tools.ietf.org, or ietf.org or of an RFC on rfc-editor.org, and a series URL at rfc-editor.org/info/ or datatracker.ietf.org/doc/ ("https://datatracker.ietf.org/doc/bcp14/"). RFCs return current and as-published status, stream, working group, obsoletes/obsoleted-by and updates/updated-by relations, the series they belong to, and the errata page; drafts return their state, IESG state, intended status, expiry, the document that replaced them, and the RFC they became; a series returns its member RFCs. Unknown ids return found: false. A call makes at most 20 Datatracker requests, retries included (an RFC or a series needs one, plus one per call for the RFCs' series; a draft three, or four with a revision suffix): each id is taken in request order if its requests still fit, and the others come back in failed with reason request_limit, to pass in another call.

Look up a registered HTTP field (header or trailer) name. Pass exactly one of `name` (case-insensitive, e.g. "Cache-Status") or `keyword` (words matched against field names and comments). Returns the registration status — permanent, provisional, deprecated, or obsoleted — the Structured Field type when registered, and the defining reference. Many widely used headers are unregistered; a miss means only that IANA has no entry.

Look up an HTTP status code in the IANA registry, or search reason phrases. Pass exactly one of `code` (100–599) or `keyword` (e.g. "too many"). Returns the registered phrase, its class, defining reference with section, and whether it is temporary, obsoleted, or unused; an unassigned code returns found: false with the unassigned range it falls in.

Parse and validate a BCP 47 language tag against the IANA Language Subtag Registry, or search subtags by description. Pass exactly one of `tag` (e.g. "zh-Hant-TW", "sr-Latn", "en_US") or `description` (e.g. "Swiss German"). A tag is split into language, extlang, script, region, variant, extension, and private-use parts; deprecated subtags report their preferred value, and a canonical tag is returned when valid. Extension singleton allocation and defining RFCs are optional metadata; allocation never validates extension content or changes base validity. A single subtag registered under several types (e.g. "TW") lists the other types.

Look up registered media (MIME) types. Pass exactly one of `type` (a full name such as "application/json"; parameters after ";" are ignored) or `keyword` (words matched against registered type names and status annotations, e.g. "geo json"; never against file extensions). An exact `type` lookup also reads the registration template and returns its file-extension, intended-usage, and deprecated-alias statements as written, each only when the template has it. Some registered types have no registration template (`template.available: false`); their references are the defining documents. Deprecated and obsoleted types are reported with their replacement when the registry names one. Unregistered "x-" types are not in the registry.

Look up a Private Enterprise Number (PEN). Pass exactly one of `pen` (a number such as 32473, or an OID under 1.3.6.1.4.1 such as 1.3.6.1.4.1.32473.1.2) or `organization` (words matched against organization names). Returns the organization and its OID prefix. Arcs below the enterprise number are assigned by the enterprise, not IANA. Contact details are not returned.

Look up IANA service name and transport protocol port assignments. Pass exactly one of `port` (a number, 0–65535), `service` (an exact service name such as "postgresql"), or `keyword` (words matched against service names and descriptions). Results list every transport (tcp, udp, sctp, dccp) separately, report the registry range row containing an unassigned port, and classify the port as System (0–1023), User (1024–49151), or Dynamic/Private (49152–65535). Service names registered without a port (DNS-SD names) appear with no port.

Look up a registered URI scheme. Pass exactly one of `scheme` (e.g. "mailto"; a trailing ":" or "://" is ignored) or `keyword` (words matched against scheme names and descriptions). Returns the status — permanent, provisional, or historical — description, references, and well-known URI support.

Find IANA protocol registries and sub-registries by keyword over their titles and protocol categories, e.g. "tls cipher", "dns resource record", "protocol numbers". Returns the registry and sub-registry ids that iana_get_registry_records reads, with registration procedure and defining documents. Covers every registry linked from the IANA protocol registries index.