---
title: ToolRouter — Use Case
description: Step-by-step guide for a real-world ToolRouter use case with agent-specific instructions.
url: https://toolrouter.com/tools/diagram-generator/use-cases/create-entity-relationship-diagrams
---
# Create Entity Relationship Diagrams

Entity relationship diagrams are the standard way to visualize database schemas. They show tables, their columns, data types, primary keys, and the relationships between tables -- one-to-one, one-to-many, many-to-many. A good ER diagram makes the data model immediately understandable to anyone on the team.

The generate_diagram skill creates ER diagrams from descriptions of your data model. List your entities with their attributes and describe how they relate to each other, and the AI produces a properly formatted diagram with standard notation for cardinality and relationships. It handles complex schemas with dozens of tables and cross-references.

Database architects use ER diagrams during design to validate their schema before writing migrations. Backend developers use them to onboard new team members onto the data model. Data analysts use them to understand which tables to join for their queries. Technical writers include them in API documentation so consumers understand the data structure behind the endpoints.

**Tool:** [Diagram Generator](https://toolrouter.com/tools/diagram-generator)
**Skills:** generate_diagram

## Agent Guides

- [How to Create ER Diagrams with Claude](https://toolrouter.com/tools/diagram-generator/use-cases/create-entity-relationship-diagrams/claude): Guide for Claude
- [How to Create ER Diagrams with ChatGPT](https://toolrouter.com/tools/diagram-generator/use-cases/create-entity-relationship-diagrams/chatgpt): Guide for ChatGPT
- [How to Create ER Diagrams with Copilot](https://toolrouter.com/tools/diagram-generator/use-cases/create-entity-relationship-diagrams/copilot): Guide for Copilot
- [How to Create ER Diagrams with OpenClaw](https://toolrouter.com/tools/diagram-generator/use-cases/create-entity-relationship-diagrams/openclaw): Guide for OpenClaw
