Streamable HTTP WWW-Authenticate Challenge Broken on 0.17.5

[ronerizon]

Inspector Version

0.17.5 latest

Describe the bug
When choosing Streamable HTTP option with WWW-Authenticate 401 protected resource challenge on MCP server, MCP inspector throws an error "Connection Error - Check if your MCP server is running and proxy token is correct"

While in 0.17.2 it works

To Reproduce
Connect to MCP server using OAuth Protected Resource WWW-Authenticate challenge in version 0.17.5

Expected behavior
MCP inspector respects the challenge and start OAuth discovery process in the end redirecting user agent to the authorization endpoint

Screenshots
0.17.5:

0.17.2 continues to authorization page

Environment (please complete the following information):

• OS: windows
• Browser chrome

Additional context
Version 0.17.2 works fine

[olaservo]

I opened a PR for this. Root cause seems to be a change in the SDK which needed some updates to Inspector. Set to a p2 since technically the older Inspector version still handles this scenario.

[segevfiner]

It's also not working for me in v0.17.2 with proxy connection mode... So I need to switch to direct, do authentication and then switch back to proxy to actually connect since the MCP server I tried doesn't support CORS -.-"

[jacopoc]

I confirm that I am experiencing the same as reported by @ronerizon and @segevfiner, i.e. Direct mode works until version 0.17.2 and doesn't work with versions 0.17.5 and 0.18.0. Proxy mode doesn't work with any version.