MCP server advertises OAuth in 401 response, causing spurious client-registration prompt in JetBrains AI Assistant

[texas697]

Summary

Every time a JetBrains IDE (WebStorm, IntelliJ) is opened with the Honcho MCP server configured, the AI Assistant panel shows the following popup:

The authorization server 'https://mcp.honcho.dev' does not support automatic client registration.
Do you want to proceed by manually providing a client registration (client ID)?

The connection still works — hitting Cancel dismisses the popup and Honcho functions normally via Bearer token auth. But the prompt appears on every IDE launch.

Root cause (hypothesis)

The MCP server at https://mcp.honcho.dev appears to include an OAuth WWW-Authenticate challenge in its 401 response. JetBrains AI Assistant's MCP client sees this, follows the OAuth discovery flow, and hits dynamic client registration — which Honcho doesn't support.

Honcho's own docs only document Bearer token / API key auth. The OAuth hint in the 401 seems unintentional and is confusing OAuth-aware MCP clients.

Config used

.ai/mcp/mcp.json (standard JetBrains AI project config):

{
  "mcpServers": {
    "honcho": {
      "url": "https://mcp.honcho.dev",
      "headers": {
        "Authorization": "Bearer <api-key>",
        "X-Honcho-User-Name": "<username>",
        "X-Honcho-Workspace-ID": "<workspace>"
      }
    }
  }
}

JetBrains reads the headers field and passes the Bearer token correctly — the green "connected" indicator confirms the connection succeeds. The OAuth popup is a side effect of the server's 401 advertising OAuth before the headers are applied.

Expected behavior

If the server authenticates successfully via Bearer token, it should not emit an OAuth WWW-Authenticate challenge that triggers client-registration flows in compliant MCP clients.

Suggested fix

• Suppress the OAuth WWW-Authenticate header on authenticated requests, or
• Don't emit it at all if Honcho doesn't intend to support a full OAuth client-registration flow

Environment

• JetBrains WebStorm (AI Assistant MCP Beta)
• https://mcp.honcho.dev (hosted)
• macOS 14+

— Jean "Claude"