guides: add agentic guide

Signed-off-by: Craig <craig.osterhout@docker.com>

Author: craig-osterhout

content/guides/agentic-ai.md

@@ -0,0 +1,314 @@
+---
+title: Build and run agentic AI applications with Docker
+linktitle: Agentic AI applications
+keywords: AI, Docker, Model Runner, MCP Toolkit, Docker Cloud, AI agents, application development
+summary: |
+  Learn how to create AI agent applications using Docker Model Runner, MCP Toolkit, and Docker Cloud.
+params:
+  tags: [AI]
+  time: 30 minutes
+---
+
+## Introduction
+
+Agentic applications are transforming how software gets built. These apps don't
+just respond, they decide, plan, and act. They're powered by models,
+orchestrated by agents, and integrated with APIs, tools, and services in real
+time.
+
+All these new agentic applications, no matter what they do, share a common
+architecture. It's a new kind of stack, built from three core components:
+
+- Models: These are your GPTs, CodeLlamas, Mistrals. They're doing the
+  reasoning, writing, and planning. They're the engine behind the intelligence.
+
+- Agent: This is where the logic lives. Agents take a goal, break it down, and
+  figure out how to get it done. They orchestrate everything. They talk to the
+  UI, the tools, the model, and the gateway.
+
+- MCP gateway: This is what links your agents to the outside world, including
+  APIs, tools, and services. It provides a standard way for agents to call
+  capabilities via the Model Context Protocol (MCP).
+
+Docker makes this AI-powered stack simpler, faster, and more secure by unifying
+models, tool gateways, and cloud infrastructure into a developer-friendly
+workflow that uses Docker Compose.
+
+![A diagram of the agentic stack](./images/agentic-ai-diagram.webp)
+
+This guide walks you through the core components of agentic development and
+shows how Docker ties them all together with the following tools:
+
+- [Docker Model Runner](../manuals/ai/model-runner/_index.md) lets you run LLMs
+  locally with simple command and OpenAI-compatible APIs.
+- [Docker MCP Catalog and
+  Toolkit](../manuals/ai/mcp-catalog-and-toolkit/_index.md) helps you discover
+  and securely run external tools, like APIs and databases, using the Model
+  Context Protocol (MCP).
+- [Docker Cloud](/cloud/) provides a powerful, GPU-accelerated
+  environment to run your AI applications with the same Compose-based
+  workflow you use locally.
+- [Docker Compose](../manuals/compose/_index.md) is the tool that ties it all
+  together, letting you define and run multi-container applications with a
+  single file.
+
+For this guide, you'll start by running the app in Docker Cloud, using the same
+Compose workflow you're already familiar with. Then, if your machine hardware
+supports it, you'll run the same app locally using the same workflow. Finally,
+you'll dig into the Compose file and app to see how it all works together.
+
+## Prerequisites
+
+To follow this guide, you need:
+
+ - [Docker Desktop 4.43 or later installed](../get-started/get-docker.md)
+ - [Docker Model Runner enabled](/ai/model-runner/#enable-dmr-in-docker-desktop)
+ - [Docker Cloud Beta joined](/cloud/get-started/)
+
+## Step 1: Clone the sample application
+
+You'll use an existing sample application that demonstrates how to connect a
+model to an external tool using Docker's AI features. This app is designed to
+run locally using Docker Compose, and it can also be run in Docker Cloud using
+the same workflow.
+
+```console
+$ git clone https://github.com/docker/compose-agents-demo.git
+$ cd compose-agents-demo/adk/
+```
+
+## Step 2: Run the application in Docker Cloud
+
+If your local machine doesn't meet the hardware requirements to run the model,
+or if you prefer to leverage cloud resources, Docker Cloud provides a fully
+managed environment to build and run containers using the Docker tools you're
+already familiar with. This includes support for GPU-accelerated instances,
+making it ideal for compute-intensive workloads like AI model inference.
+
+To run the application in Docker Cloud, follow these steps:
+
+1. Sign in to the Docker Desktop Dashboard.
+2. In a terminal, start Docker Cloud by running the following command:
+   ```console
+   $ docker cloud start
+   ```
+
+   When prompted, choose the account you want to use for Docker Cloud and select
+   **Yes** when prompted **Do you need GPU support?**.
+
+3. In the `adk/` directory of the cloned repository, run the following command
+   in a terminal to build and run the application:
+
+   ```console
+   $ docker compose up
+   ```
+
+   The model is very large. The first time you run this command,
+   Docker pulls the model from Docker Hub, which may take some time.
+
+   The application is now running in Docker Cloud. Note that the Compose workflow
+   is the same when using Docker Cloud as it is locally. You define your
+   application in a `compose.yaml` file, and then use `docker compose up` to build
+   and run it.
+
+4. Visit [http://localhost:8080](http://localhost:8080). Enter something in the
+prompt and hit enter. An agent searches DuckDuckGo and another agent revises the
+output.
+
+  ![Screenshot of the application](./images/agentic-ai-app.png)
+
+5. Press ctrl-c in the terminal to stop the application when you're done.
+
+6. Run the following command to stop Docker Cloud:
+
+```console
+$ docker cloud stop
+```
+
+## Step 3: Optional. Run the application locally
+
+If your machine meets the necessary hardware requirements, you can run the
+entire application stack locally using Docker Compose. This lets you test the
+application end-to-end, including the model and MCP gateway, without needing to
+run in the cloud. This particular example uses the 27B parameter Gemma 3 model,
+which is designed to run on high-end hardware.
+
+Hardware requirements:
+ - VRAM: 18.78GiB
+ - Storage: 16.04GB
+
+If your machine does not meet these requirements, you may still be able to run
+the application, but you will need update your `compose.yaml` file to use a
+smaller model which won't perform as well, such as `ai/gemma3-qat:4B-Q4_K_M`.
+
+To run the application locally, follow these steps:
+
+1. In the `adk/` directory of the cloned repository, run the following command in a
+   terminal to build and run the application:
+
+   ```console
+   $ docker compose up
+   ```
+
+   The model is very large. The first time you run this command, Docker pulls the
+   model from Docker Hub, which may take some time.
+
+2. Visit [http://localhost:8080](http://localhost:8080). Enter something in the
+prompt and hit enter. An agent searches DuckDuckGo and another agent revises the
+output.
+
+3. Press ctrl-c in the terminal to stop the application when you're done.
+
+## Step 4: Review the application environment
+
+The app is defined using Docker Compose, with three services:
+
+- An `adk` web app service that talks to the MCP gateway and the local model
+- A `docker-model-runner` service that runs the model
+- An `mcp-gateway` service that manages tool execution via MCP
+
+You can find the `compose.yaml` file in the `adk/` directory. Open it in a text
+editor to see how the services are defined. Comments have been added to the
+instructions below to help you understand each line.
+
+```yaml
+services:
+  adk:
+    build:
+      context: .                          # Build from the current directory
+      dockerfile: Dockerfile              # Use the specified Dockerfile
+    ports:
+      - "8080:8080"                       # Map host port 8080 to container port 8080
+    environment:
+      - MCPGATEWAY_ENDPOINT=http://mcp-gateway:8811/sse  # Tell the app where to find the MCP gateway
+    command: ["web"]                      # Start the ADK web interface
+    extra_hosts:
+      - host.docker.internal:host-gateway # Allow container to reach the host machine
+    depends_on:
+      - docker-model-runner              # Ensure model service starts before this
+      - mcp-gateway                      # Ensure gateway service starts before this
+
+  docker-model-runner:
+    provider:
+      type: model                        # Use Docker Model Runner to serve a model
+      options:
+        model: ai/gemma3-qat:27B-Q4_K_M  # Specify the model to run (27B Gemma3 QAT)
+    environment:
+      - LLAMA_ARGS=--ctx-size 20000 --jinja -ngl 100  # Runtime options for the model engine
+
+  mcp-gateway:
+    image: docker/agents_gateway:v2       # Run Docker's MCP gateway service
+    ports:
+      - "8811:8811"                       # Expose the gateway on port 8811
+    command:
+      - --transport=sse                  # Use SSE (Server-Sent Events) for agent communication
+      - --servers=duckduckgo             # Enable DuckDuckGo tool server for web search
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock  # Allow gateway to interact with Docker on host
+
+```
+
+The first notable element here is the `provider` section that specifies `type:
+model`, which lets Docker Compose know to use the Docker Model Runner component.
+The `options` section defines the specific model to run, in this case,
+[`ai/gemma3-qat:27B-Q4_K_M`](https://hub.docker.com/r/ai/gemma3-qat).
+
+> [!TIP]
+>
+> Looking for more models to use? Check out the [Docker AI Model
+> Catalog](https://hub.docker.com/catalogs/models/).
+
+The second notable element is `image: docker/agents_gateway:v2`, which indicates
+that the MCP gateway service will use the [docker/agents_gateway:v2
+image](https://hub.docker.com/r/docker/agents_gateway). This image is Docker's
+[open source MCP gateway](https://github.com/docker/docker-mcp/) that enables your application to connect to MCP servers,
+which expose tools that models can call. In this example, it uses the
+[`duckduckgo` MCP server](https://hub.docker.com/mcp/server/duckduckgo/overview)
+to perform web searches.
+
+>  [!TIP]
+>
+> Looking for more MCP servers to use? Check out the [Docker MCP
+> Catalog](https://hub.docker.com/catalogs/mcp/).
+
+Those two components, the Docker Model Runner and the MCP gateway, are the
+core of the agentic stack. They let you run models locally and connect them to
+external tools and services using the Model Context Protocol.
+
+## Step 5: Review the application
+
+The `adk` web application is an agent implementation that connects to the MCP
+gateway and a local model through environment variables and API calls. It uses
+the [ADK (Agent Development Kit)](https://github.com/google/adk-python) to
+define two agents that evaluate responses, verify claims, and revise answers.
+These agents load a language model (served via Docker Model Runner) and connect
+to external tools using the Model Context Protocol (MCP).
+
+The `adk` web application is an agent implementation that connects to the MCP
+gateway and a local model through environment variables and API calls. It uses
+the [ADK (Agent Development Kit)](https://github.com/google/adk-python) to
+define a root agent named Auditor, which coordinates two sub-agents, Critic and
+Reviser, to verify and refine model-generated answers.
+
+The three agents are:
+
+- Critic: Verifies factual claims using the toolset, such as DuckDuckGo.
+- Reviser: Edits answers based on the verification verdicts provided by the Critic.
+- Auditor: A higher-level agent that sequences the
+  Critic and Reviser. It acts as the entry point, evaluating LLM-generated
+  answers, verifying them, and refining the final output.
+
+All of the application's behavior is defined in Python under the `agents/`
+directory. Here's a breakdown of the notable files:
+
+- `agents/agent.py`: Defines the Auditor, a SequentialAgent that chains together
+  the Critic and Reviser agents. This agent is the main entry point of the
+  application and is responsible for auditing LLM-generated content using
+  real-world verification tools.
+
+- `agents/sub_agents/critic/agent.py`: Defines the Critic agent. It loads the
+  language model (via Docker Model Runner), sets the agent’s name and behavior,
+  and connects to MCP tools (like DuckDuckGo).
+
+- `agents/sub_agents/critic/prompt.py`: Contains the Critic prompt, which
+  instructs the agent to extract and verify claims using external tools.
+
+- `agents/sub_agents/critic/tools.py`: Defines the MCP toolset configuration,
+  including parsing `mcp/` strings, creating tool connections, and handling MCP
+  gateway communication.
+
+- `agents/sub_agents/reviser/agent.py`: Defines the Reviser agent, which takes
+  the Critic’s findings and minimally rewrites the original answer. It also
+  includes callbacks to clean up the LLM output and ensure it's in the right
+  format.
+
+- `agents/sub_agents/reviser/prompt.py`: Contains the Reviser prompt, which
+  instructs the agent to revise the answer text based on the verified claim
+  verdicts.
+
+The MCP gateway is configured via the `MCPGATEWAY_ENDPOINT` environment
+variable. In this case, `http://mcp-gateway:8811/sse`. This allows the app to
+use Server-Sent Events (SSE) to communicate with the MCP gateway container,
+which itself brokers access to external tool services like DuckDuckGo.
+
+## Summary
+
+This guide demonstrated how to build an agentic AI application using Docker's
+suite of tools:
+
+- [Docker Model Runner](../manuals/ai/model-runner/_index.md): Run and serve
+  open-source models locally via OpenAI-compatible APIs.
+- [Docker MCP Catalog and
+  Toolkit](../manuals/ai/mcp-catalog-and-toolkit/_index.md): Launch and manage
+  tool integrations that follow the Model Context Protocol (MCP) standard.
+- [Docker Cloud](/cloud/): Deploy and scale your application
+  in a secure, managed cloud environment.
+
+By leveraging these tools, you can develop, build, and test agentic AI applications
+efficiently and securely, using the same Docker Compose workflow you already
+know.
+
+The ADK-based agent structure used here demonstrates how to build modular,
+chain-of-thought style agentic applications. In this case, an Auditor agent
+sequences a Critic and Reviser to perform factual verification and revision of
+model-generated answers.