---
title: "Plugin parts"
description: "Choose a task in plugin parts."
canonical_url: "https://docs.oz0.ai/build/parts"
---
# Plugin parts

> Choose a task in plugin parts.

For: plugin authors.

Choose the part that owns the behaviour you are adding. An agent makes model-guided decisions, a tool exposes callable functions and a flow declares a sequence of steps. Hooks check work at defined points; connections and event sources integrate outside systems.

- [Define an agent](https://docs.oz0.ai/build/parts/agents): Set instructions, runtime, model and tools.
- [Write a tool](https://docs.oz0.ai/build/parts/tools): Expose an MCP function or a flow tool.
- [Write a flow](https://docs.oz0.ai/build/parts/flows): Connect steps, conditions and approvals.
- [Add skills](https://docs.oz0.ai/build/parts/skills): Give agents task instructions and supporting files.
- [Apply hooks](https://docs.oz0.ai/build/parts/hooks): Check tool calls and job boundaries.
- [Connect a system](https://docs.oz0.ai/build/parts/connections): Provide per-call credentials.
- [Receive events](https://docs.oz0.ai/build/parts/event-sources): Validate and normalise outside deliveries.
- [Choose a harness](https://docs.oz0.ai/build/parts/harnesses): Run an existing agent runtime as a job.


## Sitemap

See the full [sitemap](https://docs.oz0.ai/sitemap.md) for all pages.