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Connect to Open WebUI

Open WebUI 0.5+ supports MCP servers as tools. Connect V5 to make all 34 GTM tools available to any model running in your Open WebUI instance.

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Prerequisites

  • Open WebUI 0.5.0+ (self-hosted)
  • A V5 bearer token — get one from your admin: POST /admin/tokens/issue
  • Admin access to your Open WebUI instance

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Setup

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1. Add the MCP tool server

  1. Log into Open WebUI as an admin
  2. Go to Admin Panel → Settings → Tools
  3. Click Add Tool Server (or Add MCP Server)
  4. Enter:
  1. Click Save & Connect

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2. Assign to models

  1. Go to Admin Panel → Models
  2. Select the model you want to give V5 tool access
  3. Under Tool Servers, enable Ascend Gateway V5
  4. Save

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3. Test in chat

Start a chat with the configured model:

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Docker compose configuration

If running Open WebUI with Docker, you can pre-configure the MCP server via environment variables:

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Tool usage in chat

When composing a message, click the Tools icon in the chat input to see and enable specific V5 tools for that conversation. Enable only the tools relevant to your task — this reduces context overhead.
V5 has 34 tools. Enabling all 34 simultaneously adds significant token overhead to each message. Select only the tools you need for the current task.

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Troubleshooting

“Failed to connect to tool server”
Open WebUI must be able to reach ascend-gateway-v5.ascendgtm.workers.dev from your server. Check network connectivity and firewall rules if self-hosting. Tools show but model doesn’t use them
Ensure you’re using a function-calling-capable model (GPT-4, Claude, Gemini, or a tool-capable local model). Pure text completion models don’t support tool use.