Error Connecting to MCP Inspector Proxy

[electricbrain-code]

Inspector Version

• MCP Inspector v0.19.0 where the tag describes this as a "hotfix"

Describe the bug
When pressing the "connect" button the UI reports "Error Connecting to MCP Inspector Proxy". I'm trying to fix the security issue with the proxy being available on the host network - which a priori - is entirely configurable (copied from the bottom).

The environment is Docker Swarm running on ARM64 Pi hosts.

To Reproduce
Run the container as per this Portainer script:
mcp-inspector:
deploy:
placement:
constraints:
- "node.labels.arch == aarch64"
- "node.labels.public == true"
- "node.hostname == hostx.localdomain"
mode: replicated
replicas: 1
environment:
- ALLOWED_ORIGINS=http://mcp-inspector.mgt-network:6274,http://mcp-inspector.xx-network:6274,http://mcp-server-openhab.xx-network:8000
- DANGEROUSLY_OMIT_AUTH=true
- DEBUG=mcp:* #<-- Doesn't work.
- HOST=0.0.0.0
- MCP_AUTO_OPEN_ENABLED=false
- MCP_PROXY_FULL_ADDRESS=http://mcp-inspector.xx-network:6277 #<- Available via curl from inside container
image: registry:5000/ghcr.io/modelcontextprotocol/inspector:latest #<-- Local repo
networks:
- xx_network
- mgt_network
- external_network #<-- Lets me apt load debug stuff
# ports: #<-- If this is here everything work well. Major security issue - not allowed here.
# - target: 6277
# published: 6277
# protocol: tcp
volumes:
- /docker/mcp-inspector/etc/mcp-inspector:/etc/mcp-inspector

1. Go to UI and click "Gear Icon" Configuration.
2. Anter the Inspector Proxy Address field and add "http://mcp-inspector.xx-network:6277" #<-- reachable via curl.
3. Click Connect button
4. See error "Error Connecting to MCP Inspector Proxy - Check Console logs"

Expected behavior
The Inspector should connect to its proxy (which is will do with the Ports section active - but which is a major security issue)

Screenshots

Environment (please complete the following information):

• OS: Ubuntu Linux
• Browser Firefox

Additional context
I am unable to find any debug log or even activate such. CoPilot thinks everything goes to stdout and stderr, but this is all that is seen:

@modelcontextprotocol/inspector@0.19.0 start
node client/bin/start.js
Starting MCP inspector...
⚙️ Proxy server listening on 0.0.0.0:6277
⚠️ WARNING: Authentication is disabled. This is not recommended.
🚀 MCP Inspector is up and running at:
http://0.0.0.0:6274

Other that this issue everything works well. I'm trying to fix the security issue - which a priori - is entirely configurable. Any help is most welcome.

Version Consideration

Inspector V2 is under development to address architectural and UX improvements. During this time, V1 contributions should focus on bug fixes and MCP spec compliance. See CONTRIBUTING.md for more details.