DiagramGPT — Eraser

How to generate and use a use case diagram

Tips on making a Use Case Diagram

• Instead of writing a prompt from scratch, consider pasting excerpts from existing documents such as requirements docs, user manuals, knowledge base articles that describe the system and the use cases.
• Working with an LLM to create a fleshed out diagram prompt can be effective. Describe a system and ask it to create a list of user and use case pairings.

1. Write a prompt describing how users interact with the system
   A simple one-liner can work too but the best prompts are usually at least 3-4 sentences long. Applying the below framework generally yields good results:

   • Make sure to describe users (e.g. student, teachers) and use cases (e.g. submit homework, view grades).
   • Include the visual requirements of a use case diagram to the prompt: “A use case diagram consists of users and use cases. Users are rectangle shapes and use cases are oval shapes. Connections between users and use cases show what users have what use cases; don’t add any other connections. Put use cases in a group called use cases. Don’t put users in a group and don’t group use cases by users. Mention “Use Case Diagram” in the title.”

2. Make a diagram with the completed prompt

3. Edit the diagram with follow-up prompts (this step requires signing in to Eraser)

4. Manually adjust the layout using GUI controls (this step requires signing into Eraser)

Generate any type of diagram with AI

Supported Diagram Types

• Architecture
• Swimlane
• Sequence
• Flowchart
• ERD
• Data Flow
• Network
• AWS
• Azure
• Terraform
• Kubernetes
• and more...

Frequently asked questions

• Can I edit the generated use case diagram?
  Yes. Click “Save and Edit Diagram” to open it in Eraser, where you can edit using diagram-as-code syntax or the visual GUI.

• What can I use as a prompt?
  Plain English, a nested list, or a code snippet. You can also paste excerpts from requirements docs, transcripts, or knowledge-base articles.

• Can I use this from an AI agent?
  Yes. Eraser runs an MCP server, so any MCP-compatible client – Claude, Cursor, or ChatGPT – can create and edit these diagrams directly. See the MCP catalog for what it exposes.

• Who created this tool?
  The use case diagram maker was created by the team at Eraser, leveraging frontier AI models. Eraser is an AI tool for technical design and documentation.

• Is it free?
  Generating a use case diagram is free and requires no sign-up. Sign in to a free Eraser account to edit, save, and export your diagrams.

• Is there an API?
  Yes, you can read our API documentation. The API is only available to Starter, Business, and Enterprise Plan teams.

• Is there an MCP server?
  Yes. The Eraser MCP server lets an agent create, search, read, update and export diagrams from clients like Claude, Cursor, VS Code and ChatGPT. It is free to use, subject to the AI credit limits of your plan.

• Do you use my data to train AI models?
  No. Neither Eraser nor our model providers use your data to train AI models. Eraser may analyze usage to improve and enhance our AI features.

• How do I get started?
  Describe what you need in the prompt box above and generate. You can keep refining the result with follow-up prompts.

• What’s next for this tool?
  It only gets better from here. We’re working to improve accuracy and layout customization. If there’s something you’d like to see, drop us a note at hello@eraser.io.

• How do I get in touch?
  We’d love to hear from you. Reach out at hello@eraser.io, on X (@eraserlabs), or join our Slack community.