> NOTICE — Pre-launch build. Every record here is a dated observation of a real MCP endpoint operated by a third party, rendered from the published archive. Coverage is partial — the figures cover the snapshots in the export this build was made from, not the whole chain and not the whole ecosystem. Claims and badges are not open.

# 21st.dev/api/mcp

Last observed: 2026-10-02T09:22:33.286Z
Recorded as: AUTH_REQUIRED (http_401)
Transport: streamable-http
Observations held: 58
Published: yes

## Observations

| Observed | Snapshot | Recorded as | Detail | Latency ms | Tools | Tool schema fingerprint |
|---|---|---|---|---|---|---|
| 2026-08-06T17:46:09.651Z | REL-SNAP-002 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-07T08:32:14.455Z | REL-SNAP-003 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-08T10:13:32.855Z | REL-SNAP-004 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-09T08:55:10.226Z | REL-SNAP-005 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-10T08:51:12.255Z | REL-SNAP-006 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-11T08:55:43.883Z | REL-SNAP-007 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-12T08:54:38.886Z | REL-SNAP-008 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-13T08:48:58.847Z | REL-SNAP-009 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-14T09:00:54.360Z | REL-SNAP-010 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-15T08:50:46.088Z | REL-SNAP-011 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-16T08:51:45.935Z | REL-SNAP-012 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-17T11:23:28.061Z | REL-SNAP-013 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-18T08:50:37.861Z | REL-SNAP-014 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-19T08:42:15.042Z | REL-SNAP-015 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-20T08:50:36.839Z | REL-SNAP-016 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-21T09:06:27.050Z | REL-SNAP-017 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-22T08:43:27.153Z | REL-SNAP-018 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-23T09:44:41.717Z | REL-SNAP-019 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-24T08:46:48.649Z | REL-SNAP-020 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-25T08:48:42.111Z | REL-SNAP-021 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-26T08:44:47.920Z | REL-SNAP-022 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-27T08:57:10.361Z | REL-SNAP-023 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-28T08:55:52.399Z | REL-SNAP-024 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-29T08:45:30.535Z | REL-SNAP-025 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-30T08:47:30.862Z | REL-SNAP-026 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-08-31T08:50:05.444Z | REL-SNAP-027 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-01T08:45:53.150Z | REL-SNAP-028 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-02T08:53:10.551Z | REL-SNAP-029 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-03T09:15:18.391Z | REL-SNAP-030 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-04T09:01:59.901Z | REL-SNAP-031 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-05T08:49:13.142Z | REL-SNAP-032 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-06T09:00:08.293Z | REL-SNAP-033 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-07T09:12:45.867Z | REL-SNAP-034 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-08T09:05:48.176Z | REL-SNAP-035 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-09T09:00:27.307Z | REL-SNAP-036 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-10T09:34:15.580Z | REL-SNAP-037 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-11T09:33:36.686Z | REL-SNAP-038 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-12T09:25:04.149Z | REL-SNAP-039 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-13T09:52:14.405Z | REL-SNAP-040 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-14T09:53:09.633Z | REL-SNAP-041 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-15T09:45:52.014Z | REL-SNAP-042 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-16T10:10:05.978Z | REL-SNAP-043 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-17T09:54:24.472Z | REL-SNAP-044 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-18T09:44:19.397Z | REL-SNAP-045 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-19T09:30:10.943Z | REL-SNAP-046 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-20T09:46:09.384Z | REL-SNAP-047 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-21T09:27:08.642Z | REL-SNAP-048 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-22T09:42:51.511Z | REL-SNAP-049 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-23T10:03:05.733Z | REL-SNAP-050 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-24T09:59:05.188Z | REL-SNAP-051 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-25T09:55:26.435Z | REL-SNAP-052 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-26T09:31:58.746Z | REL-SNAP-053 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-27T09:44:29.621Z | REL-SNAP-054 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-28T09:59:53.435Z | REL-SNAP-055 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-29T09:46:52.256Z | REL-SNAP-056 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-09-30T09:50:56.750Z | REL-SNAP-057 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-10-01T09:26:42.244Z | REL-SNAP-058 | AUTH_REQUIRED | http_401 | - | - | - |
| 2026-10-02T09:22:33.286Z | REL-SNAP-059 | AUTH_REQUIRED | http_401 | - | - | - |

## Identity

Record key: 21st.dev/api/mcp (the normalised endpoint observed)
Registry names (not anchored — no inclusion proof reaches this field): dev.21st/mcp (what the registry said when we swept it, as observed by us — not evidence that the registry was correct, that the name belongs to whoever registered it, or that it still resolves)
Name reported by the server: not reported (self-reported, unverified, never used as identity)

Each observation carries a merkle leaf in the snapshot it belongs to. The chain
establishes that a root existed by a given time; it does not establish that any
measurement is true.