---
title: "Schema-as-ontology (JSON Schema / OpenAPI) · agent building block · Agent Fieldbook"
url: https://agentfieldbook.org/design/building_blocks/json-schema/
description: "Tools and actions are defined as typed JSON Schema / OpenAPI: the agent knows each tool's inputs, outputs and constraints from the schema itself."
section: "Design · Building Blocks · Ontology"
source: Agent Fieldbook — generated from the published page
---

# Schema-as-ontology (JSON Schema / OpenAPI)

Tools and actions are defined as typed JSON Schema / OpenAPI: the agent knows each tool's inputs, outputs and constraints from the schema itself.

## How it works

## At a glance

| Field | Value |
| --- | --- |
| Kind | Ontology· Schema |
| Example | AWS Bedrock Action Groups |

## Basis

- [docs.aws.amazon.com](https://docs.aws.amazon.com/bedrock/latest/userguide/agents-action-create.html)