Mellow Hub: MCP server, CLI and agent surfaces
Sign-in required, tools not seen, not counted. The MCP endpoint listed for Mellow Hub at www.mellow.world answered 401 with OAuth metadata on 4 November 2026. Its tools can be listed only after a person authorizes a client, and this directory never signs in.
Fact sheet
| Company | Mellow Hub |
|---|---|
| Domain | mellow.world |
| Category | Marketing (assigned by this directory from the registry description) |
| MCP server | Sign-in required (OAuth with client registration) |
| Ora score | none: Ora returned no cached score for mellow.world when asked on 5 November 2026 |
| Company found through | the GitHub MCP Registry |
| Last verified | 4 November 2026 |
MCP server
| Endpoint | https://www.mellow.world/mcp |
|---|---|
| How it was found | listed in the GitHub MCP Registry |
| Transport | streamable-http |
| HTTP status | 401 |
| Connected | 4 November 2026, 20:03 UTC |
| Handshake time | 1,493 ms over 2 attempts |
| Result | initialize error: Header mismatch: MCP-Protocol-Version header is required. |
The endpoint answered the handshake with a sign-in challenge, so the tool list is not visible to this directory. It is not counted as an MCP server: a sign-in challenge is its own state, and the connector listed no tools.
Connector log
2 connections on 4 November 2026, read-only methods only
- 19:58:23Z https://www.mellow.world/mcp sent initialize, initialize result auth-required (HTTP 401) 1430 ms
- 20:03:39Z https://www.mellow.world/mcp sent initialize, initialize result auth-required (HTTP 401) 1493 ms
Authentication
| Auth type | OAuth with client registration |
|---|---|
| What the challenge said | Bearer realm="Mellow Hub", resource_metadata="https://www.mellow.world/.well-known/oauth-protected-resource", scope="channels:read channels:connect media:write posts:read posts:write posts:publish metrics:read" |
| Protected resource metadata | www.mellow.world |
| Authorization server metadata | www.mellow.world |
| Registration endpoint | https://www.mellow.world/api/hub/oauth/register |
The sign-in route, step by step
- Request
https://www.mellow.world/mcpwithout a token. It answers 401 and aWWW-Authenticateheader. - Read the protected resource metadata at
https://www.mellow.world/.well-known/oauth-protected-resourceto find the authorization server. - Register a client at the registration endpoint
https://www.mellow.world/api/hub/oauth/register(dynamic client registration), so no human has to create an app first. - Send a person through the authorization page, then retry the endpoint with the bearer token. The connector stops after step 2 and never authorizes.
See OAuth for MCP: client ID metadata documents and dynamic registration for how each route works.
CLI
No CLI is on record for Mellow Hub. The directory checks a package only where a source names one, so this is a floor: a company can ship a command line that no source read for this edition mentions. See shipping a CLI agents can use.
Other agent surfaces
| Surface | Result |
|---|---|
| OpenAPI file | No OpenAPI file at the root paths checked. |
| WebMCP in the initial HTML | Not checked: the home page was not read by the shared crawl. |
| MCP discovery file | Not checked: the domain is not in the shared crawl for this edition. |
| A2A agent card | Not checked: the domain is not in the shared crawl for this edition. |
| A2A agent card (older path) | Not checked: the domain is not in the shared crawl for this edition. |
| agents.json | Not checked: the domain is not in the shared crawl for this edition. |
| OAuth authorization server metadata | Not checked: the domain is not in the shared crawl for this edition. |
| NLWeb endpoint | Not checked in this edition. |
Registry listings
| Registry | Listed |
|---|---|
| Official MCP Registry | No |
| GitHub MCP Registry | Yes |
| awesome-remote-mcp-servers | No |
| Smithery | Not checked: Smithery's listing pages and search API were unavailable on 4 November 2026. |
| Glama | Not checked: Glama's API needs a key and attribution terms. |