Index / ARD publishers / 21st.dev

21st.dev

21st.dev publishes an Agentic Resource Discovery manifest at /.well-known/ard.json, declaring what an AI agent can call on this domain. Everything below is read from that file. First seen by our crawler on 16 September 2026.

6declared resources
6with a callable endpoint
6answering of 6 checked
0verified tools

Declared resource	Type
21st API cataloganswers in 340ms endpoint: `https://21st.dev/.well-known/api-catalog` identifier: `urn:air:21st.dev:catalog:api-catalog` published to be found for: what APIs does 21st.dev expose · where is the 21st.dev OpenAPI spec	application/linkset+json
21st MCP setupanswers in 74ms Connection and authentication guide for the 21st MCP server, including its Streamable HTTP endpoints. endpoint: `https://21st.dev/mcp.md` identifier: `urn:air:21st.dev:mcp:21st` published to be found for: how do I connect an MCP client to 21st · what is the read-only 21st MCP endpoint · how does an agent authenticate to the 21st MCP server · where are the 21st MCP setup instructions	text/markdown
21st llms.txtanswers in 55ms Product summary for AI assistants, including the Magic MCP / Magic Chat name bridge and the map of markdown page twins. endpoint: `https://21st.dev/llms.txt` identifier: `urn:air:21st.dev:docs:llms-txt` published to be found for: what is 21st.dev · is Magic MCP the same as 21st MCP · how do I browse 21st.dev as markdown	text/plain
Agent authentication for 21stanswers in 346ms How an agent obtains credentials: OAuth 2.1 with dynamic client registration for MCP, or a user-issued API key. endpoint: `https://21st.dev/auth.md` identifier: `urn:air:21st.dev:auth:agent-registration` published to be found for: how does an agent authenticate to 21st.dev · register an OAuth client for the 21st MCP server	text/markdown
21st REST APIanswers in 262ms REST API for search, install and publish; the same surface the CLI and MCP server call. endpoint: `https://21st.dev/openapi.json` identifier: `urn:air:21st.dev:api:rest-v1` published to be found for: search 21st.dev components over HTTP · publish a React component to 21st.dev from a script · get the install command for a 21st component	application/vnd.oai.openapi+json;version=3.0
21st agent skillsanswers in 261ms Agent skills (SKILL.md) for the 21st CLI and design workflow: 21st-cli-use, 21st-ai, 21st-registry, 21st-design-sync, 21st-ui-build, 21st-ui-explore, 21st-ui-review, 21st-video. endpoint: `https://21st.dev/.well-known/skills/index.json` identifier: `urn:air:21st.dev:skills:index` published to be found for: how does an agent use the 21st CLI · publish a component to 21st.dev with an agent skill · build UI grounded in the project's design system with 21st	application/json

Source: https://21st.dev/.well-known/ard.json, this publisher's own file. Identifiers are reproduced exactly as published. Of the resources listed, 6 have been probed for reachability. "Answers" and "no response" describe only whether an endpoint replied when last probed: services go down and come back, and an entry is demoted rather than removed. None of this is a trust, quality or safety rating.

Search this publisher's resources alongside every other indexed resource at https://neuronto.com/search, or connect an agent to https://neuronto.com/mcp. If this is your domain, the free console shows what a registry sees when it reads your manifest. To hear when any of it changes, publisher monitoring is $19 a month, the first 14 days free.