Fully local MCP integration with Open WebUI & Ollama

[ValentinVie]

Hi !

First of all thank you for trek, it's great and works really well !
I'm trying to set up a fully local MCP integration using Open WebUI and Ollama but I'm hitting an issue where the LLM does not see the available tools.

Here is the OpenWeb UI Integration setup :

Here is the conversation sample. I'm using qwen3:30b and it does not detect the Trek tool set it is supposed to use :

Few details :

• I have successfully integrated the MCP with Claude, it seems the issue does not come from my Trek instance configuration or reverse proxy configuration.
• My trek instance is public trek.example.com (Cloudflare disabled, SSO setup) and my open-webui instance is internal (with HTTPS & SSO setup) open-webui.internal.example.com. Trek can resolve the DNS for the Open Webui internal domain.
• I'm using Caddy as the reverse proxy for both trek and Open WebUI. I have one Caddy internal proxy, one Caddy internet facing proxy with Crowdsec. Crowdsec does not appear to block any request.

Here are the logs where it seems a new session OAuth is created every time, I don't really know why.

trek  | 2026-08-03T21:03:01.573685797Z [MCP] Session sweep: cleaned 0, active 1
trek  | 2026-08-03T21:04:34.764813956Z [MCP] POST without mcp-session-id for user 3 — starting a new session. If this repeats on every tool call, the Mcp-Session-Id response header is not reaching the client (check that your reverse proxy forwards it).
trek  | 2026-08-03T21:04:34.786469127Z [MCP] Session 09a0e6dd-e60a-41a1-a1b1-bb2b2c5a2103 created for user 3 [oauth(trips:read,trips:write,trips:share,places:read,places:write,atlas:read,atlas:write,packing:read,packing:write,todos:read,todos:write,budget:read,budget:write,reservations:read,reservations:write,collab:read,collab:write,notifications:read,notifications:write,vacay:read,vacay:write,geo:read,weather:read,journey:read,journey:write,journey:share)]. Active sessions: 1
trek  | 2026-08-03T21:05:01.573635313Z [MCP] Session sweep: cleaned 0, active 1
trek  | 2026-08-03T21:06:01.573616346Z [MCP] Session sweep: cleaned 0, active 1
trek  | 2026-08-03T21:07:42.704569173Z [MCP] POST without mcp-session-id for user 3 — starting a new session. If this repeats on every tool call, the Mcp-Session-Id response header is not reaching the client (check that your reverse proxy forwards it).
trek  | 2026-08-03T21:07:42.724387342Z [MCP] Session ee0ef28c-bf76-4ad0-b073-6b03d3dbc0d8 created for user 3 [oauth(trips:read,trips:write,trips:share,places:read,places:write,atlas:read,atlas:write,packing:read,packing:write,todos:read,todos:write,budget:read,budget:write,reservations:read,reservations:write,collab:read,collab:write,notifications:read,notifications:write,vacay:read,vacay:write,geo:read,weather:read,journey:read,journey:write,journey:share)]. Active sessions: 1
trek  | 2026-08-03T21:08:01.575383284Z [MCP] Session sweep: cleaned 0, active 1
trek  | 2026-08-03T21:09:01.575590030Z [MCP] Session sweep: cleaned 0, active 1
trek  | 2026-08-03T21:10:12.336241573Z [MCP] POST without mcp-session-id for user 3 — starting a new session. If this repeats on every tool call, the Mcp-Session-Id response header is not reaching the client (check that your reverse proxy forwards it).
trek  | 2026-08-03T21:10:12.354226873Z [MCP] Session dd0b30c1-031f-4c88-a66b-b829cadd3d8d created for user 3 [oauth(trips:read,trips:write,trips:share,places:read,places:write,atlas:read,atlas:write,packing:read,packing:write,todos:read,todos:write,budget:read,budget:write,reservations:read,reservations:write,collab:read,collab:write,notifications:read,notifications:write,vacay:read,vacay:write,geo:read,weather:read,journey:read,journey:write,journey:share)]. Active sessions: 1
trek  | 2026-08-03T21:11:01.576596277Z [MCP] Session sweep: cleaned 0, active 1
trek  | 2026-08-03T21:15:04.941915602Z [INFO] 2026-08-03T23:15:04 me@example.com oauth.consent.grant ip=82.65.xxx.xxx <--> My public IP
trek  | 2026-08-03T21:15:05.085368514Z [INFO] 2026-08-03T23:15:05 me@example.com oauth.token.issue ip=82.65.xxx.xxx
trek  | 2026-08-03T21:15:11.195894518Z [MCP] POST without mcp-session-id for user 3 — starting a new session. If this repeats on every tool call, the Mcp-Session-Id response header is not reaching the client (check that your reverse proxy forwards it).
trek  | 2026-08-03T21:15:11.215758282Z [MCP] Session 0af47dc0-9661-40b4-9dc9-ebc11480b41f created for user 3 [oauth(trips:read,trips:write,trips:share,places:read,places:write,atlas:read,atlas:write,packing:read,packing:write,todos:read,todos:write,budget:read,budget:write,reservations:read,reservations:write,collab:read,collab:write,notifications:read,notifications:write,vacay:read,vacay:write,geo:read,weather:read,journey:read,journey:write,journey:share)]. Active sessions: 1
trek  | 2026-08-03T21:16:01.577227860Z [MCP] Session sweep: cleaned 0, active 1
trek  | 2026-08-03T21:22:11.643533329Z [MCP] POST without mcp-session-id for user 3 — starting a new session. If this repeats on every tool call, the Mcp-Session-Id response header is not reaching the client (check that your reverse proxy forwards it).

After all, Open WebUI is pretty clear : "MCP support is experimental and its specification changes often, which can lead to incompatibilities."

I'm wondering if anyone had any success with Trek MCP +OpenWeb UI & Ollama ?
Thanks !