Replacing Stage Agents

Each pipeline stage has a default AI Task Agent that handles it automatically. You can replace any of them with a custom agent — one you've installed from the Yao Agents Hub or built yourself.

## When to replace a stage agent

The defaults work well for most Robots. Replace a stage agent when:

- The default agent doesn't fit the Robot's specific domain (e.g. you want a specialized research agent for the Inspiration stage)
- You've built a custom agent that formats output in a specific way the Delivery stage should use
- You want to inject domain-specific validation logic in the Validation stage
- You're fine-tuning a high-volume Robot and want tighter control over each step

You don't need to replace every stage — replace only the ones where the default behavior isn't what you need.

## How to replace a stage agent

Open the Robot in **Mission Control**, go to **Settings → Advanced**, and scroll to the **Execution Pipeline** section. Each stage has a dropdown — set to "Use global default" by default.

![Advanced settings — Execution Pipeline section with per-stage agent dropdowns](https://assets.yaoagents.com/en/mission/02-mission-create-advanced-2-en-$__THEME.png)

1. Click the dropdown for the stage you want to customize
2. Select a replacement agent from the list
3. Click **Save Changes**

The custom agent takes effect on the next run.

> 💡 Not sure which agent to use? Check the Yao Agents Hub for community-built stage agents, or ask the General Assistant to help you evaluate options.

## Reverting to the default

To go back to the default agent for a stage:

1. Open the Robot's **Identity** tab
2. Click the customized stage
3. Select **Default** from the agent list
4. Save

## Constraints

- A custom agent must declare itself compatible with the pipeline stage role it's replacing. Incompatible agents won't appear in the selection list.
- If a custom agent is deleted from your hub, the stage falls back to the default automatically on the next run.

## What's next

- [Pipeline Overview](/docs/en-us/mission-control/execution-pipeline/pipeline-overview) — understand what each stage does
- [Yao Agents Hub](/docs/en-us/agent-hub/hub-overview) — find or install agents you can use as stage replacements
- [Custom AI Experts](/docs/en-us/agent-hub/custom-assistants) — build your own agent to slot into a pipeline stage