Acornonaut MCP Server
warningsmcp.acornonaut.app
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https://mcp.acornonaut.appOAuthlast checked 3 Sep 2026spoke MCP on 3 of 3 checks (30 days)initialize in 134 msWill my client connect?
Decided from what the probe found at the endpoint, and from what each client's own documentation says it can complete. Every row carries the day that documentation was read.
✕Claude CodeNot supported
The authorization server advertises no S256 challenge method, which MCP's authorization spec requires — no compliant client has a method in common with it.
Claude Code docs · read on 2026-08-30
✕Claude (claude.ai & Desktop)Not supported
The authorization server advertises no S256 challenge method, which MCP's authorization spec requires — no compliant client has a method in common with it.
Claude (claude.ai & Desktop) docs · read on 2026-08-30
✕ChatGPTNot supported
The authorization server advertises no S256 challenge method, which MCP's authorization spec requires — no compliant client has a method in common with it.
ChatGPT docs · read on 2026-08-30
✕CursorNot supported
The authorization server advertises no S256 challenge method, which MCP's authorization spec requires — no compliant client has a method in common with it.
Cursor docs · read on 2026-08-30
✕VS Code (Copilot)Not supported
The authorization server advertises no S256 challenge method, which MCP's authorization spec requires — no compliant client has a method in common with it.
VS Code (Copilot) docs · read on 2026-08-30
How to authenticate
Checked against the endpoint by our probe on 3 Sep 2026. These are the capabilities the server advertises, not a prediction about any particular client.
| Scheme | OAuth |
|---|---|
| Issuer | https://mcp.acornonaut.app |
| Dynamic client registration | ✓Advertised (RFC 7591) |
| Client ID Metadata Document | ✕Not advertised |
| PKCE | ✕None advertised MCP requires S256; a client that implements only that has no method in common with this server. |
| Grant types | authorization_code |
| Protected-resource metadata | ✓Published (RFC 9728) |
| Anonymous access | Refused — credentials required |
What the probe found
A cross-origin preflight came back without Access-Control-Allow-Origin, so the endpoint is reachable from native clients only — code running in a web page is stopped by the browser before a request is ever sent.
Contract history
No contract recorded yet — the server has not answered an anonymous connection.
Run this server? A verified owner can publish snapshots with their own credentials, and the contract history starts here, marked owner-reported.
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Status badge
Status for a README, from the last probe — cached an hour, so up to seven hours behind the endpoint. Links back to this page.
[](https://mcpi.app/servers/acornonaut-mcp-server)