Part 2 of 7 in the Logic Apps Agent Loop series

Part 1 explained why the Azure Logic Apps agent loop is a different design paradigm from conventional workflow automation. This post gets hands-on with the anatomy of that loop. We will look at the four building blocks that make up every agent loop trigger, instructions, connected model, and tools, and walk through how to wire them together in a Standard logic app.

By the end of this post you will have a working autonomous agent that accepts a prompt from a trigger, reasons over it using Azure OpenAI, invokes a connector action as a tool, and returns a result. The run history will show you exactly how the loop iterated.

The Azure Logic Apps agent loop: four building blocks

Before opening the designer, it helps to have a clear mental model of what you are assembling. Every Azure Logic Apps agent loop consists of four parts.

Trigger

The trigger starts the workflow, exactly as it does in any nonagentic Logic Apps workflow. For an autonomous agent, this can be any supported trigger an HTTP request, a timer, a Service Bus message, a new email, or anything else in the connector library. The trigger’s output becomes the initial input to the agent: the prompt or data the model will reason over.

Instructions

Instructions are the system prompt for the agent. You provide them as a block of natural language text in the agent action’s configuration pane. They define the agent’s role, what it can and cannot do, how it should respond, and any constraints it should observe. A well-written instructions block is the single most important factor in how well the agent performs. Think of it as the job description you hand to the model at the start of every run.

Connected model

The agent needs a language model to reason with. In Standard Logic Apps, you connect the agent to an Azure OpenAI Service resource and specify the model deployment to use — typically a GPT-4o deployment. The agent sends the instructions, the trigger input, and the results of any tool calls to the model at each iteration of the loop. The model’s response tells the agent what to do next.

Tools

A tool is a sequence of one or more connector actions that the agent can choose to invoke. You build tools directly in the Logic Apps designer by adding actions from the connector gallery inside the agent action. Each tool gets a name and a description — the model uses these to decide which tool to call and when. A single agent can have multiple tools. An agent with no tools can still respond to prompts using the model’s built-in knowledge, but it cannot take action on external systems.

The diagram below shows how these four parts fit together inside a single agent loop execution.

Building your first agent loop in Azure Logic Apps

The demo for this post is deliberately simple: an agent that receives a topic via an HTTP trigger, uses Azure OpenAI to generate a summary, and returns the result to the caller. One trigger, one model, one tool is enough to see all four building blocks in action and to read a meaningful run history.

Prerequisites

• A Standard logic app resource deployed in Azure
• An Azure OpenAI Service resource with a GPT-4o model deployment
• Contributor access to both resources

Step 1: Create the workflow

In the Azure portal, open your Standard logic app and select Workflows from the sidebar. Choose Add, then select Autonomous Agents as the workflow type. Give the workflow a name and select Stateful. Logic Apps creates a new workflow with an empty agent action already in place.

Step 2: Configure the trigger

The autonomous agent workflow template starts with a When a HTTP request is received trigger by default. Leave the method as POST. In the request body JSON schema, add a single property: topic of type string. This is the input the agent will work with.

Step 3: Write the instructions

Select the agent action in the designer to open its configuration pane. On the Parameters tab, find the Instructions field. Enter something like the following:

You are a research assistant. When given a topic, use the available tools to retrieve relevant information and return a concise summary of no more than three sentences. Always cite your source.

Keep instructions specific and bounded. Vague instructions produce unpredictable behaviour. The model will take the instructions literally, so precision matters.

Step 4: Connect the model

Still on the Parameters tab, select Add connection under the model configuration section. Choose Azure OpenAI Service, select your resource, and choose your GPT-4o deployment. Logic Apps establishes the connection and stores it against the workflow.

Step 5: Add a tool

Inside the agent action, select Add a tool. This opens the connector gallery filtered to actions that can be used as tools. For this demo, add the HTTP action as a tool — name it search_web, give it the description “Retrieves content from a given URL”, and configure it to accept a URL as input. In a production scenario you would use Azure AI Search or a more capable connector here; the HTTP action keeps the demo self-contained.

Step 6: Save and run

Save the workflow. Use a REST client to POST a JSON body like {"topic": "Azure Logic Apps agent loop"} to the workflow’s trigger URL. The agent fires, the model reasons over the instructions and the topic, invokes the search tool, and returns a summary.

Reading the run history

he run history is where the Azure Logic Apps agent loop becomes visible. Open the workflow’s Run history and select the latest run. You will see the trigger, followed by the agent action. Expand the agent action and you will find each iteration of the loop shown as a numbered step: the model’s reasoning output, the tool call with its inputs and outputs, and the model’s decision on whether to loop again or return a final answer.

This is the key difference from a nonagentic run history. In a conventional workflow, the run history shows a flat list of actions. In an agent loop, it shows a nested, iterative structure the model’s chain of thought made visible.

For a simple prompt, you may see a single iteration. For a more complex task involving multiple tool calls, you will see the loop unfold across three, five, or more steps. Each step shows exactly what the model decided and why.

Standard versus Consumption: model connections

In Standard logic apps, you configure the model connection yourself — selecting an Azure OpenAI Service resource and specifying the deployment. This gives you full control over which model version you use, where it is hosted, and how it is secured via Managed Identity.

In Consumption logic apps (currently in public preview), the model connection is handled via Microsoft Foundry and the configuration is more constrained. For any production workload, Standard remains the right choice.

What comes next

The agent in this post is autonomous it runs without human interaction, triggered by an HTTP call and returning a result when done. That covers a wide range of integration scenarios, but not all of them. Some tasks require a back-and-forth with a user: a support conversation, a guided data-entry flow, a multi-turn research session.

The next part will cover exactly that distinction, autonomous versus conversational agentic workflows, and walk through when to choose each pattern and what changes in the designer when you do.