google__adk-docs/docs/agents/workflow-agents/sequential-agents.md

Sequential template workflow agent

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

The SequentialAgent class is a template workflow agent that executes its sub-agents in the order they are specified in a list. Use SequentialAgent when you want execution to occur in a fixed, strict order. As with other templated workflows, the execution of a SequentialAgent object is not controlled by an AI model, and is deterministic in how it executes its sub-agents. The sub-agents specified in the sequential execution set may or may not utilize AI models, but the overall execution of those sub-agents is ultimately managed by the SequentialAgent object you define.

!!! note "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Starting in ADK 2.0 for Python and Go, templated workflows have been superseded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](/graphs/) and
[dynamic workflows](/graphs/dynamic/).

Example scenario

You want to build an agent that can summarize any webpage, using two tools: Get Page Contents and Summarize Page. Since the agent must always call Get Page Contents before calling Summarize Page, you can build your agent using the SequentialAgent class.

How it works

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

1. Iteration: It iterates through the sub agents list in the order they were provided.
2. Sub-Agent Execution: For each sub-agent in the list, it calls the sub-agent's Run Async method.

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!!! note "Shared Invocation Context" The SequentialAgent passes the same InvocationContext to each of its sub-agents. This means they all share the same session state, including the temporary (temp:) namespace, making it easy to pass data between steps within a single turn.

Full Example: Code Development Pipeline

Consider a simplified code development pipeline:

• Code Writer Agent: An LLM Agent that generates initial code based on a specification.
• Code Reviewer Agent: An LLM Agent that reviews the generated code for errors, style issues, and adherence to best practices. It receives the output of the Code Writer Agent.
• Code Refactorer Agent: An LLM Agent that takes the reviewed code, and the reviewer's comments, and refactors it to improve quality and address issues.

Using a SequentialAgent makes it simple to define this exection flow, as shown in the following code snippet:

SequentialAgent(sub_agents=[CodeWriterAgent, CodeReviewerAgent, CodeRefactorerAgent])

This ensures the code is written, then reviewed, and finally refactored, in a strict, dependable order. The output from each sub-agent is passed to the next by storing them in state via Output Key.

???+ "Code"

=== "Python"
    ```py
    --8<-- "examples/python/snippets/agents/workflow-agents/sequential_agent_code_development_agent.py:init"
    ```

=== "TypeScript"
    ```typescript
    --8<-- "examples/typescript/snippets/agents/workflow-agents/sequential_agent_code_development_agent.ts:init"
    ```

=== "Go"
    ```go
    --8<-- "examples/go/snippets/agents/workflow-agents/sequential/main.go:init"
    ```

=== "Java"
    ```java
    --8<-- "examples/java/snippets/src/main/java/agents/workflow/SequentialAgentExample.java:init"
    ```

!!! tip "Global instructions for all agents"

Apply consistent rules or identity across all agents in your workflow using  `GlobalInstructionPlugin` registered on your `App` or `Runner` object. Do not use the `global_instruction` parameter on `Agent` which is deprecated since ADK Python v1.16.0.