> For a complete page index, fetch https://docs.synthflow.ai/llms.txt. For full documentation content, fetch https://docs.synthflow.ai/llms-full.txt.

# Background audio on running actions

> Custom actions and MCP tools can play background audio while they run.

![Action audio selection for a custom action](https://storage.googleapis.com/granular-changelog/doc-images/action_audio.png)

[Custom actions](/about-custom-actions#play-audio-while-the-action-runs) and individual [MCP tools](/mcp-actions#play-audio-while-an-mcp-tool-runs) can now play background audio while they run, giving callers feedback during slower requests.