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Open WebUI MCP Server Setup: OAuth 2.1, Keys and mcpo

Add a remote Open WebUI MCP server: the admin Integrations path, OAuth 2.1 or a bearer key, per-chat tools, the mcpo route and one real X search's cost.


Published · Updated · 6 min read

Cover image: X research inside Open WebUI

Open WebUI MCP support is native since v0.6.31: an admin adds the server as an MCP Streamable HTTP connection under Settings, Admin, Integrations.

This guide adds Weir, so your Open WebUI models can search X (Twitter) and read posts, threads and profiles. Weir only reads, so it never posts as you. We run Weir.

Type:  MCP (Streamable HTTP)
Name:  Weir
ID:    weir
URL:   https://api.weirapp.io/mcp
Auth:  OAuth 2.1

Open WebUI MCP setup: add Weir in five steps

You need admin rights on Open WebUI 0.6.31 or later, and a free Weir account.

We read Open WebUI v0.12.3, released 16 October 2026: its docs and its source.

  1. Open IntegrationsGo to Settings, then Admin, then Integrations. Under External Tool Servers, click + to add a connection.
  2. Switch the typeClick OpenAPI next to Type, so it reads MCP Streamable HTTP.
  3. Fill in the formURL https://api.weirapp.io/mcp, name Weir, ID weir. Set Auth to OAuth 2.1.
  4. Register and saveClick Register Client, then Save.
  5. Connect in a chatOpen Integrations in the message box, then Tools, and turn Weir on. Approve Weir in your browser.

Which auth should an Open WebUI MCP connection use?

Use OAuth 2.1 when several people share Open WebUI, and Bearer when it's only you.

Auth What Open WebUI sends With Weir
None Nothing Fails with 401
Bearer The key you paste One account pays for all
Session The user's Open WebUI token Fails
OAuth The user's SSO token Fails
OAuth 2.1 A token from Weir's sign-in Each user signs in
OAuth 2.1 (Static) Your own client ID and secret Not needed

Bearer is the quick route. Create a key under API keys in your Weir dashboard and paste it into Key. An empty Key sends a bare Authorization: Bearer, which Weir rejects.

Every chat that uses the tool then spends that key's credits.

Does Open WebUI MCP support OAuth?

Yes. Open WebUI 0.6.31 shipped OAuth 2.1 with dynamic client registration, next to native MCP.

  • There's no client ID to paste. Register Client signs Open WebUI up with Weir under the name "Open WebUI".
  • Each person connects their own account. The first time someone turns Weir on in a chat, Open WebUI sends them to Weir. Nobody else gets that grant.
  • Your address must be HTTPS or localhost. The callback sits at Open WebUI's own address, and Weir accepts only https or local http. A LAN address like http://192.168.1.20:3000 fails.
  • Revoke it in Weir. Each link shows as "Open WebUI (MCP)" under API keys in that person's Weir dashboard.

How to turn on Open WebUI MCP tools per chat or per model

Turn Weir on per chat: open Integrations in the message box, pick Tools and switch Weir on.

  • Per model is Workspace, then Models, then the Tools row. Skip it for OAuth 2.1: until a user signs in, chats fail with "Failed to connect to MCP server".
  • Trim the list with Function Name Filter List, such as search_x, get_usage. Weir lists 44 tools on a default sign-in.
  • The model sees weir_search_x. Open WebUI puts the connection ID in front of each tool name.
  • Calls run without asking by default. An admin can turn on the experimental Tool Permissions under Settings, Admin, Interface. Then pick Ask for approval in the + menu.

Open WebUI uses the model's native function calling by default since v0.10.0. Its docs warn that small local models often write broken tool calls, and suggest a current model built for tools.

Can Open WebUI search X (Twitter)? A worked task

Yes, through Weir, so ask for Open WebUI's latest news:

Use weir: what's the latest @OpenWebUI post on X? Skip replies and reposts.

The model should call weir_search_x. We ran that call through Weir's MCP server on 24 October 2026:

→ search_x {"fromUsers": ["OpenWebUI"], "query": "-filter:nativeretweets",
            "onlyOriginal": true, "since": "2026-10-01T00:00:00Z", "limit": 1}
← 1 post · 2 credits (1 + 1 × 1) · nextCursor set
  Oct 16  18 likes  1,361 views  "More local compute. Put it to work."

The post names Open WebUI an early access partner for NVIDIA RTX Spark. -filter:nativeretweets drops reposts, which X search returns by default, and onlyOriginal drops replies.

2credits for our 1-post search
11credits for a 10-post search
0credits for get_usage
5,000free Weir credits every month

Weir bills 1 credit per call plus 1 per X post, and failed calls are free. Packs start at $5 for 25,000 credits and never expire, as of October 2026. See every rate on our pricing page.

Open WebUI MCP through mcpo: the older route

Before v0.6.31, MCP servers reached Open WebUI through mcpo, its proxy that turns an MCP server into an OpenAPI one. Its docs now suggest it for stdio and SSE servers.

Weir speaks Streamable HTTP, so you don't need it. If you already run mcpo, its README gives this form:

uvx mcpo --port 8000 --api-key "top-secret" --server-type "streamable-http" \
  --header '{"Authorization": "Bearer weir_live_your_key"}' -- https://api.weirapp.io/mcp

Then add http://localhost:8000 as an OpenAPI connection, with Bearer set to top-secret. From Docker, use host.docker.internal instead of localhost.

What we haven't tested

We didn't install Open WebUI or mcpo here. This guide comes from their docs and source, plus a real call through Weir's MCP server.

  • Open WebUI's sign-in against Weir. Its registration matches what Weir accepts, but we haven't clicked through it.
  • The mcpo command. We built it from mcpo's README and haven't run it.

If it doesn't work

  • Register Client fails. Check your Open WebUI address is HTTPS or localhost, or switch to Bearer.
  • "Failed to connect to MCP server". Remove Weir from the model's default tools, or check that Bearer has a key.
  • The page loads forever after you save. The type was left on OpenAPI. Delete the connection and add it as MCP.
  • A tool returns 402. Your Weir credits ran out, and retrying won't help.

When not to use Weir

  • You want to stay fully offline. Weir is a remote service, so each call goes over the internet.
  • The model has to post or DM. Weir is read-only.
  • Price per post matters most. TwitterAPI.io lists $0.15 per 1,000 tweets as of October 2026, less than our $5 pack.
  • You need a guarantee. Weir isn't licensed by X or affiliated with it, so access can change.

FAQ

Can users add their own MCP servers in Open WebUI?

No. Only admins can, by design, Open WebUI's docs say. Users with the Direct Tool Servers permission can add their own OpenAPI servers instead.

Does Open WebUI support stdio or SSE MCP servers?

Not natively: its MCP support is Streamable HTTP only. Run a stdio or SSE server behind mcpo, then add it as an OpenAPI connection.

Is the Open WebUI MCP integration stable?

Open WebUI's docs call it "supported and improving", and the connection form calls MCP support experimental. They still name OpenAPI the preferred route for most deployments.

Can Open WebUI post to X through Weir?

No. Weir only reads public X data, so nothing can post, like or follow through it.

Sources

All checked on 24 October 2026:

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