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Loop template workflow agent

Supported in ADKPython v0.1.0TypeScript v0.2.0Go v0.1.0Java v0.2.0

The LoopAgent class is a template workflow agent that executes its sub-agents in a loop for a specified number of iterations or until a termination condition is met. Use the LoopAgent when your workflow involves repetition or iterative refinement, such as revising code or a document. As with other templated workflows, the execution of a LoopAgent object is not controlled by an AI model, and is deterministic in how it executes its sub-agents. The sub-agents within the defined loop may or may not utilize AI models, but the overall execution of those sub-agents is ultimately managed by the LoopAgent object you define.

Alternative: graph-based workflows

Starting in ADK 2.0 for Python and Go, templated workflows have been superseded

by more flexible workflow structures, including graph-based workflows and dynamic workflows.

Example scenario

You want to build an agent that can generate images of food, but sometimes when you want to generate a specific number of items, such as bananas, the agent generates a different number of those items in the image, such as an image of 7 bananas. You have two tools: Generate Image, Count Food Items. If your goal is to keep generating images until it either correctly generates the specified number of items, or after a certain number of iterations, you can build your agent using a LoopAgent workflow.

How it Works

When the LoopAgent's Run Async method is called, it performs the following actions:

  1. Sub-Agent Execution: It iterates through the Sub Agents list in order. For each sub-agent, it calls the agent's Run Async method.

  2. Termination Check:

    Crucially, the LoopAgent itself does not inherently decide when to stop looping. You must implement a termination mechanism to prevent infinite loops. Common strategies include:

    • Max Iterations: Set a maximum number of iterations in the LoopAgent. The loop will terminate after that many iterations.