diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index c9e74b9b..e7d01afb 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -120,6 +120,16 @@ updates:
     schedule:
       interval: "daily"
 
+  - directory: "/application/open-webui"
+    package-ecosystem: "docker-compose"
+    schedule:
+      interval: "daily"
+
+  - directory: "/application/open-webui/init"
+    package-ecosystem: "docker"
+    schedule:
+      interval: "daily"
+
   - directory: "/application/ingestr"
     package-ecosystem: "pip"
     schedule:
diff --git a/.github/workflows/application-open-webui.yml b/.github/workflows/application-open-webui.yml
new file mode 100644
index 00000000..19a190c9
--- /dev/null
+++ b/.github/workflows/application-open-webui.yml
@@ -0,0 +1,56 @@
+name: "Open WebUI"
+
+on:
+  pull_request:
+    paths:
+    - '.github/workflows/application-open-webui.yml'
+    - 'application/open-webui/**'
+  push:
+    branches: [ main ]
+    paths:
+    - '.github/workflows/application-open-webui.yml'
+    - 'application/open-webui/**'
+
+  # Allow job to be triggered manually.
+  workflow_dispatch:
+
+  # Run job each night after CrateDB nightly has been published.
+  #schedule:
+  #  - cron: '0 3 * * *'
+
+# Cancel in-progress jobs when pushing to the same branch.
+concurrency:
+  cancel-in-progress: true
+  group: ${{ github.workflow }}-${{ github.ref }}
+
+jobs:
+
+  test:
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      fail-fast: true
+      matrix:
+        os: [ "ubuntu-latest" ]
+
+    name: OS ${{ matrix.os }}
+
+    env:
+      OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
+
+    steps:
+
+      - name: Acquire sources
+        uses: actions/checkout@v4
+
+      - name: Validate application/open-webui
+        run: |
+          # TODO: Generalize invocation into `ngr` test runner.
+
+          # Invoke software stack.
+          cd application/open-webui
+          docker compose up --detach
+
+          # Invoke validation payload.
+          # TODO: Currently does not work on GHA.
+          # docker compose run --rm test
diff --git a/application/open-webui/.env b/application/open-webui/.env
new file mode 100644
index 00000000..e3d01049
--- /dev/null
+++ b/application/open-webui/.env
@@ -0,0 +1,9 @@
+# ------------------------------------------
+#            User configuration
+# ------------------------------------------
+
+# Define your OpenAI API key here if you want to make it persistent.
+# You can also use other models with Open WebUI, however that is
+# currently out of the scope of this miniature rig.
+
+# OPENAI_API_KEY=your_openai_api_key
diff --git a/application/open-webui/README.md b/application/open-webui/README.md
new file mode 100644
index 00000000..8909b6b3
--- /dev/null
+++ b/application/open-webui/README.md
@@ -0,0 +1,131 @@
+# Use CrateDB with Open WebUI
+
+## About
+
+A complete end-to-end rig including CrateDB, CrateDB MCPO, and Open WebUI,
+including a touch of integration tests on CI/GHA.
+
+This stack is intended solely for demonstration purposes and does **not**
+implement any security hardening. Do **not** deploy it to production.
+
+## Introduction
+
+[Open WebUI] is an extensible, feature-rich, and user-friendly self-hosted AI
+platform designed to operate entirely offline. It supports various LLM runners
+like Ollama and OpenAI-compatible APIs, with built-in inference engine for RAG,
+making it a powerful AI deployment solution.
+
+CrateDB MCPO is an adapter wrapper around the [CrateDB MCP] server. Because
+Open WebUI uses [OpenAPI Tool Servers] to integrate external tooling and data
+sources into LLM agents and workflows, standard MCP servers need to adapt to
+how [Open WebUI MCP Support] works.
+
+## Usage
+
+### Sources
+
+It is advised to clone the Git repository and run the demo stack from there.
+In this spirit, it will be easy for you to receive updates.
+```shell
+git clone https://github.com/crate/cratedb-examples
+cd cratedb-examples/application/open-webui
+```
+
+### Start services
+
+Configure the API key for OpenAI within the `.env` file next to `compose.yml`
+to make it persistent for unattended service operations.
+```dotenv
+# .env
+OPENAI_API_KEY=your_openai_api_key_here
+```
+Or export it for a one-off run:
+```shell
+export OPENAI_API_KEY=your_openai_api_key_here
+```
+
+Spin up the software stack. On the first occasion, it will take a while to
+download the OCI images and let Open WebUI do its thing when bootstrapping
+the very first time.
+```shell
+docker compose up
+```
+
+### User interface
+
+You can access the service's resources on those URLs.
+
+- CrateDB: http://localhost:4200/
+- Open WebUI: http://localhost:6200/
+
+Explore the APIs here.
+
+- CrateDB MCPO: 
+  - Swagger: http://localhost:5200/docs
+  - OpenAPI: http://localhost:5200/openapi.json
+- Open WebUI: 
+  - Swagger: http://localhost:6200/docs
+  - OpenAPI: http://localhost:6200/openapi.json
+- Jupyter:
+  - http://localhost:7200/
+
+### Configure
+
+To make the ensemble work well, you need to configure a few bits on the Open WebUI
+user interface.
+
+- Make sure to enable the "CrateDB" tool. The toggle switch is located within the
+  flyout menu on the left side of the query prompt, which can be opened using the
+  `More (+)` button.
+
+- In the "Chat Controls" flyout widget, located in the top right corner of the page,
+  - make sure to enable `Function Calling: Native`, see [OPEN-WEBUI-15939],
+  - and dial down to `Temperature: 0.0`.
+
+### Example questions
+
+Enjoy conversations with CrateDB (talk to your data) and its documentation
+(talk to your knowledgebase).
+
+- Text-to-SQL: _What is the average value for sensor 1?_
+- Knowledgebase: _How do I use CrateDB with SQLAlchemy?_
+
+### Stop services
+Tear down services.
+```shell
+docker compose down
+```
+Delete all volumes.
+```shell
+docker compose down --volumes
+```
+Delete individual volumes.
+```shell
+docker volume rm open-webui_open-webui
+```
+```shell
+docker volume rm open-webui_cratedb
+```
+
+### Jobs
+Invoke individual jobs defined in the Compose file.
+```shell
+export BUILDKIT_PROGRESS=plain
+docker compose run --rm setup
+docker compose run --rm test
+```
+
+## What's inside
+
+- `.env`: The dotenv file defines `OPENAI_API_KEY` for `compose.yml`.
+- `compose.yml`: The service composition file defines four main services:
+  CrateDB, CrateDB MCPO, Open WebUI, and Jupyter. Helper jobs (setup, test, ...)
+  excluded for brevity. Use it with Docker or Podman.
+- `init/`: Runtime configuration snippets.
+
+
+[CrateDB MCP]: https://cratedb.com/docs/guide/integrate/mcp/cratedb-mcp.html
+[OpenAPI Tool Servers]: https://docs.openwebui.com/openapi-servers/
+[Open WebUI]: https://docs.openwebui.com/
+[Open WebUI MCP Support]: https://docs.openwebui.com/openapi-servers/mcp/
+[OPEN-WEBUI-15939]: https://github.com/open-webui/open-webui/issues/15939#issuecomment-3108279768
diff --git a/application/open-webui/compose.yml b/application/open-webui/compose.yml
new file mode 100644
index 00000000..0d395cc0
--- /dev/null
+++ b/application/open-webui/compose.yml
@@ -0,0 +1,179 @@
+# Use CrateDB with Open WebUI
+#
+# https://cratedb.com/docs/
+# https://docs.openwebui.com/getting-started/quick-start
+---
+networks:
+  llm-demo:
+    name: llm-demo
+    driver: bridge
+
+volumes:
+  cratedb:
+  open-webui:
+  jupyter:
+
+services:
+
+  # -------
+  # CrateDB
+  # -------
+  cratedb:
+    image: docker.io/crate/crate:6.0.0
+    environment:
+      CRATE_HEAP_SIZE: 2g
+    ports:
+      - "4200:4200"
+      - "5432:5432"
+    command: [
+      "crate",
+      "-Cdiscovery.type=single-node",
+      "-Ccluster.routing.allocation.disk.threshold_enabled=false",
+    ]
+    networks:
+      - llm-demo
+    volumes:
+      - cratedb:/data
+    healthcheck:
+      test: [ "CMD", "curl", "--fail", "http://localhost:4200" ]
+      start_period: 3s
+      interval: 10s
+
+  # ------------
+  # CrateDB MCPO
+  # ------------
+  cratedb-mcpo:
+    image: ghcr.io/crate/cratedb-mcpo:0.0.7
+    environment:
+      CRATEDB_CLUSTER_URL: http://crate:crate@cratedb:4200/
+    ports:
+      - "5200:8000"
+    networks:
+      - llm-demo
+    healthcheck:
+      test: [ "CMD", "curl", "--fail", "http://localhost:8000/docs" ]
+      start_period: 3s
+      interval: 10s
+    depends_on:
+      cratedb:
+        condition: service_healthy
+
+  # ----------
+  # Open WebUI
+  # ----------
+  open-webui:
+    image: ghcr.io/open-webui/open-webui:0.6.18
+    # https://docs.openwebui.com/getting-started/env-configuration
+    # https://docs.openwebui.com/getting-started/api-endpoints/#swagger-documentation-links
+    environment:
+      # From caller's environment or `.env` file.
+      OPENAI_API_KEY: ${OPENAI_API_KEY}
+      # Currently defined here.
+      ENABLE_SIGNUP: "false"
+      ENABLE_LOGIN_FORM: "false"
+      WEBUI_AUTH: "false"
+      DEFAULT_MODELS: "gpt-4.1"
+      DEFAULT_USER_ROLE: "admin"
+      ENABLE_CHANNELS: "true"
+      RESPONSE_WATERMARK: "This text is AI generated"
+      WEBUI_NAME: "CrateDB LLM Cockpit"
+      BYPASS_MODEL_ACCESS_CONTROL: "true"
+      ENABLE_OLLAMA_API: "false"
+      ENABLE_OPENAI_API: "true"
+      ENABLE_DIRECT_CONNECTIONS: "true"
+      ENV: "dev"
+      # Jupyter code execution and interpreter.
+      ENABLE_CODE_INTERPRETER: "true"
+      CODE_EXECUTION_ENGINE: "jupyter"
+      CODE_EXECUTION_JUPYTER_URL: "http://jupyter:8888"
+      CODE_EXECUTION_JUPYTER_AUTH: "token"
+      CODE_EXECUTION_JUPYTER_AUTH_TOKEN: "123456"
+      CODE_EXECUTION_JUPYTER_TIMEOUT: 60
+      CODE_INTERPRETER_ENGINE: "jupyter"
+      CODE_INTERPRETER_JUPYTER_URL: "http://jupyter:8888"
+      CODE_INTERPRETER_JUPYTER_AUTH: "token"
+      CODE_INTERPRETER_JUPYTER_AUTH_TOKEN: "123456"
+      CODE_INTERPRETER_JUPYTER_TIMEOUT: 60
+    ports:
+      - "6200:8080"
+    networks:
+      - llm-demo
+    volumes:
+      - open-webui:/app/backend/data
+    healthcheck:
+      test: [ "CMD", "curl", "--fail", "http://localhost:8080" ]
+      start_period: 3s
+      interval: 10s
+      retries: 60
+      timeout: 90s
+    depends_on:
+      cratedb-mcpo:
+        condition: service_healthy
+      jupyter:
+        condition: service_healthy
+
+  # -------
+  # Jupyter
+  # -------
+  jupyter:
+    image: quay.io/jupyter/minimal-notebook:notebook-7.4.4
+    # https://docs.openwebui.com/tutorials/jupyter/
+    environment:
+      JUPYTER_ENABLE_LAB: "yes"
+      JUPYTER_TOKEN: "123456"
+    ports:
+      - "7200:8888"
+    networks:
+      - llm-demo
+    volumes:
+      - jupyter:/home/jovyan/work
+    healthcheck:
+      test: [ "CMD", "curl", "--fail", "http://localhost:8888" ]
+      start_period: 3s
+      interval: 10s
+      retries: 60
+      timeout: 90s
+
+  # -----
+  # Setup
+  # -----
+  setup:
+    build:
+      context: init
+    command: bash /app/setup.sh
+    networks:
+      - llm-demo
+    depends_on:
+      cratedb:
+        condition: service_healthy
+      cratedb-mcpo:
+        condition: service_healthy
+      open-webui:
+        condition: service_healthy
+
+  # ----
+  # Test
+  # ----
+  test:
+    build:
+      context: init
+    command: bash /app/test.sh
+    networks:
+      - llm-demo
+    depends_on:
+      setup:
+        condition: service_completed_successfully
+    deploy:
+      replicas: 0
+
+  # -------
+  # Bundler
+  # -------
+  # Wait for all defined services to be fully available by probing their health
+  # status, even when using `docker compose up --detach`.
+  # https://marcopeg.com/2019/docker-compose-healthcheck/
+  start-dependencies:
+    image: docker.io/dadarek/wait-for-dependencies
+    depends_on:
+      setup:
+        condition: service_completed_successfully
diff --git a/application/open-webui/init/.env b/application/open-webui/init/.env
new file mode 100644
index 00000000..a6977fcc
--- /dev/null
+++ b/application/open-webui/init/.env
@@ -0,0 +1,9 @@
+# ------------------------------------------
+#           System configuration
+# ------------------------------------------
+
+# If you run `setup.sh` from within the Docker Compose
+# environment, you will not need to change those settings.
+
+CRATEDB_URL=http://cratedb:4200
+OPEN_WEBUI_URL=http://open-webui:8080
diff --git a/application/open-webui/init/Dockerfile b/application/open-webui/init/Dockerfile
new file mode 100644
index 00000000..22fbea3f
--- /dev/null
+++ b/application/open-webui/init/Dockerfile
@@ -0,0 +1,34 @@
+FROM python:3.13-slim-bookworm
+
+# Configure operating system.
+ENV DEBIAN_FRONTEND=noninteractive
+ENV TERM=linux
+
+RUN set -e \
+    && apt-get update \
+    && apt-get --yes install --no-install-recommends --no-install-suggests curl jq \
+    && rm -rf /var/lib/apt/lists/*
+
+# Install and configure `uv`.
+# Guidelines that have been followed.
+# - https://hynek.me/articles/docker-uv/
+
+# Install the `uv` package manager.
+COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv
+COPY --from=ghcr.io/astral-sh/uv:latest /uvx /usr/local/bin/uvx
+
+# - Tell uv to byte-compile packages for faster application startups.
+# - Silence uv complaining about not being able to use hard links.
+# - Prevent uv from accidentally downloading isolated Python builds.
+# - Install packages into the system Python environment.
+ENV \
+    UV_COMPILE_BYTECODE=true \
+    UV_LINK_MODE=copy \
+    UV_PYTHON_DOWNLOADS=never \
+    UV_SYSTEM_PYTHON=true
+
+RUN uv pip install crash cratedb-mcp httpie
+
+RUN mkdir /app
+WORKDIR /app
+COPY .env *.sh *.json *.sql /app/
diff --git a/application/open-webui/init/init.sql b/application/open-webui/init/init.sql
new file mode 100644
index 00000000..f38cff8e
--- /dev/null
+++ b/application/open-webui/init/init.sql
@@ -0,0 +1,25 @@
+DROP TABLE IF EXISTS time_series_data;
+
+CREATE TABLE IF NOT EXISTS time_series_data (
+    "timestamp" TIMESTAMP,
+    value DOUBLE,
+    location STRING,
+    sensor_id INT
+);
+
+INSERT INTO time_series_data ("timestamp", value, location, sensor_id)
+VALUES
+    ('2023-09-14T00:00:00', 10.5, 'Sensor A', 1),
+    ('2023-09-14T01:00:00', 15.2, 'Sensor A', 1),
+    ('2023-09-14T02:00:00', 18.9, 'Sensor A', 1),
+    ('2023-09-14T03:00:00', 12.7, 'Sensor B', 2),
+    ('2023-09-14T04:00:00', 17.3, 'Sensor B', 2),
+    ('2023-09-14T05:00:00', 20.1, 'Sensor B', 2),
+    ('2023-09-14T06:00:00', 22.5, 'Sensor A', 1),
+    ('2023-09-14T07:00:00', 18.3, 'Sensor A', 1),
+    ('2023-09-14T08:00:00', 16.8, 'Sensor A', 1),
+    ('2023-09-14T09:00:00', 14.6, 'Sensor B', 2),
+    ('2023-09-14T10:00:00', 13.2, 'Sensor B', 2),
+    ('2023-09-14T11:00:00', 11.7, 'Sensor B', 2);
+
+REFRESH TABLE time_series_data;
diff --git a/application/open-webui/init/setup.sh b/application/open-webui/init/setup.sh
new file mode 100755
index 00000000..96dacf81
--- /dev/null
+++ b/application/open-webui/init/setup.sh
@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+
+# Configure Open WebUI via HTTP API.
+
+# Runtime options.
+set -euo pipefail
+
+# Uncomment for local debugging, but **never** in automated runs.
+# set -x
+
+# Load configuration.
+source .env
+
+# -------
+# CrateDB
+# -------
+
+# Provision database.
+crash --hosts ${CRATEDB_URL} < init.sql
+
+# ----------
+# Open WebUI
+# ----------
+
+# Sign in to receive JWT token.
+token=$( http --ignore-stdin POST ${OPEN_WEBUI_URL}/api/v1/auths/signin email= password= | jq -r .token )
+if [[ -z "${token}" ]]; then
+  echo "FATAL: Could not obtain JWT token from Open WebUI" >&2
+  exit 1
+fi
+
+# Inquire health.
+http --ignore-stdin ${OPEN_WEBUI_URL}/health
+
+# List available tools.
+http --ignore-stdin ${OPEN_WEBUI_URL}/api/v1/tools/ Authorization:"Bearer $token"
+
+# Configure system prompt.
+http --ignore-stdin ${OPEN_WEBUI_URL}/api/v1/users/user/settings/update Authorization:"Bearer $token" \
+    ui[system]="$( cratedb-mcp show-prompt )" \
+    ui[params][function_calling]="native" \
+    ui[params][temperature]:=0.0 \
+    ui[notificationEnabled]="true"
+
+# Configure CrateDB MCPO server.
+http --ignore-stdin ${OPEN_WEBUI_URL}/api/v1/configs/tool_servers Authorization:"Bearer $token" \
+    "@tool-servers.json"
+
+# Configure chat model.
+http --ignore-stdin ${OPEN_WEBUI_URL}/api/v1/configs/models Authorization:"Bearer $token" \
+    DEFAULT_MODELS="gpt-4.1" MODEL_ORDER_LIST="[]"
+
+# Configure embedding model.
+http --ignore-stdin ${OPEN_WEBUI_URL}/api/v1/retrieval/embedding/update Authorization:"Bearer $token" \
+    embedding_engine="openai" embedding_model="text-embedding-3-small"
diff --git a/application/open-webui/init/test.sh b/application/open-webui/init/test.sh
new file mode 100644
index 00000000..57124386
--- /dev/null
+++ b/application/open-webui/init/test.sh
@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+# Test Open WebUI configuration via HTTP API.
+
+# Runtime options.
+set -euo pipefail
+
+# Uncomment for local debugging, but **never** in automated runs.
+# set -x
+
+# Load configuration.
+source .env
+
+# Sign in to receive JWT token.
+token=$( http --ignore-stdin POST ${OPEN_WEBUI_URL}/api/v1/auths/signin email= password= | jq -r .token )
+if [[ -z "${token}" ]]; then
+  echo "FATAL: Could not obtain JWT token from Open WebUI" >&2
+  exit 1
+fi
+
+# Check for a canonical available model to validate that Open WebUI configuration worked.
+http ${OPEN_WEBUI_URL}/api/models Authorization:"Bearer $token" refresh==true | \
+    grep '"id":"gpt-4.1"' >/dev/null 2>&1 || {
+        echo "ERROR: Model gpt-4.1 not available"
+        exit 1
+    }
+
+echo "gpt-4.1 model found"
+echo "Ready."
diff --git a/application/open-webui/init/tool-servers.json b/application/open-webui/init/tool-servers.json
new file mode 100644
index 00000000..ff65f05e
--- /dev/null
+++ b/application/open-webui/init/tool-servers.json
@@ -0,0 +1,18 @@
+{
+  "TOOL_SERVER_CONNECTIONS": [
+    {
+      "url": "http://cratedb-mcpo:8000",
+      "path": "openapi.json",
+      "auth_type": "bearer",
+      "key": "",
+      "config": {
+        "enable": true,
+        "access_control": null
+      },
+      "info": {
+        "name": "CrateDB",
+        "description": "CrateDB Text-to-SQL and documentation inquiry."
+      }
+    }
+  ]
+}
\ No newline at end of file