AI Chat Copilot

Why Use AI with Astah?

AI Chat Copilot helps you model faster and communicate designs more clearly.

• Reduce time spent on first drafts
  Generate diagram proposals directly from requirements, feature descriptions, or rough ideas.
  
  
• Improve clarity in reviews
  Summarize complex diagrams in plain language for quick understanding and sharing.
  
  
• Bridge text and structure
  Convert unstructured ideas into formal designs without starting from a blank canvas.
  
  
• Iterate with confidence
  Refine diagrams through follow-up prompts and explore alternatives efficiently.

What AI Chat Copilot Can Do

Copilot supports your modeling with three core actions:

1. Generate diagrams from text

Describe a system, feature, or scenario in your own words, and Copilot proposes diagrams.

Supported Diagram types:

• Class Diagram
• UseCase Diagram
• Sequence Diagram
• Activity Diagram
• Statemachine Diagram
• ER Diagram

2. Summarize and interpret existing diagrams

Ask Copilot to:

• Explain a diagram in plain language
• Highlight key flows or main scenarios
• Describe responsibilities and relationships between elements

This is useful for documentation, onboarding, and design reviews – even when stakeholders use different languages.

3. Refine and expand designs

Use conversation to:

• Improve the structure of your diagrams
• Check for missing elements or inconsistencies
• Request additional details or alternative designs

Copilot helps you iterate quickly, while you keep full control over what is applied to your models.

For more scenarios and prompt examples for design workflows, model analysis, documentation generation, and code integration — see: Detailed Scenarios & Prompt Examples

Quick Start

You can begin using Copilot in just a few steps.

1. Create a new or open .asta file
   
   
2. Open the Chat Copilot pane
   Select the Chat Copilot tab in the Extra view which you can open from [View] – [Show/Hide Extra View].
   
   
   
   
3. Settings
   Click Settings in the Chat Copilot view and select which AI services and models you want to use, along with other options. For more details, see the Settings section below.
   
   
   
   
4. Enter your prompt:
   In the User Prompt area, type what you want to model or understand. You can write naturally in your preferred language – no special syntax is required.
   
   
5. Send and review results
   Click Send Prompt. Copilot’s response appears in the Output area. Use the result as a draft and refine it in Astah as needed.

Tip: To start a new conversation, click New Chat in the upper-right of the pane.

Settings

Enable and Configure AI Chat Copilot

To use AI Chat Copilot, you need to enable AI features and confirm your connection settings.

Configuration Steps

1. Open Settings in the Chat Copilot view, then configure the following sections.
   
   
   

1. AI Settings

• AI Service:
  Select the AI Service to use.
  Available options: OpenAI / Claude / Gemini / OpenAI-compatible.
  
  
• URL:
  Specify the base URL of the selected AI service API.
  This field is editable only when “OpenAI-compatible” is selected.
  
  
• API Key:
  Enter the API key for the AI service.
  Generate and obtain your API key from your AI service provider.
  
  
• Model Name:
  Select or enter the AI model to use.
  After setting the API key, click [Apply] to fetch the list of available models.
  
  
• Creativity (Temperature):
  Adjust how creative or deterministic the responses should be. Higher values produce more creative and varied outputs. The available range may vary depending on the model and AI service.
  
  
• Context Window Size:
  Set the context window size for the AI. You can leave this unset to rely on the automatic control. A larger value allows longer responses, but increases cost. The available range depends on the AI model. For details, refer to the specifications of your AI service.
  

2. General

Configure general behavior of AI Chat Copilot.

• Prompt History Size:
  Set how many entered prompts are kept in history.
  Note: Astah AI Chat Copilot does not store the history of AI outputs (responses).
  
  
• Edit Mode:
  Allows the AI to edit models. This is enabled by default.
  Turn this off if you want to restrict AI to “read-only” assistance.
  
  
• Debug Mode:
  This outputs detailed logs.
  Log file location: (User Home)/.astah/professional or uml/astah-copilot.log
  
  
• Allow Local File Access:
  Allows the AI to read local files. Click [Edit] to set allowed paths. Please take extra care when granting access to folders that contain confidential information.

3. Proxy

Configure network connection settings.

• Use System Proxy Settings: Enable this to connect to the AI service using the system proxy settings.

4. MCP

You do not need to configure MCP section if you only use AI Chat Copilot inside Astah.
Configure settings if you want to integrate Astah with external AI clients that support MCP.

Notes and Limitations

• AI Chat Copilot relies on an external AI service.
• AI-generated results may be incomplete or inaccurate.
• Always review and validate diagrams before use.
• Do not enter confidential or sensitive information unless permitted by your organization’s policies.

Token Limitations

• AI services have an upper limit on the number of tokens they can process.
• Sending or receiving very large specifications or model data in a single request may:
  • Reduce response quality
  • Cause timeout or errors
  • Make processing unstable
• Try to adjust your prompts so that the exchanged information does not become excessively long.

Updating AI Chat Copilot

AI Chat Copilot is provided as a plug-in.
When updates with bug fixes or improvements become available, we provide an updated plug-in .jar file. Follow the steps below to update Chat Copilot to the latest version.

How to Update AI Chat Copilot

1. Download the latest AI Chat Copilot .jar file.
   Currently the latest version is bundled with Astah Professional / Astah UML version 11.
   
   
2. Drag and drop the .jar file into the Astah window while Astah is running.
   
   
3. Restart Astah to apply the update.

Current Version Information

• Latest AI Chat Copilot Version: 1.0 (Released on 2025/12/17)
• Bundled Astah Version: Astah Professional / Astah UML Version 11

How to Check Your Installed AI Chat Copilot Version

1. Open [Plugin] → [Installed Plugin].
   
   
   
2. A list of installed plug-ins will appear.
   
   
3. Locate “Astah AI Chat Copilot” and check the Version column.
   

How to uninstall AI Chat Copilot

1. Open [Plugin] → [Installed Plugin].
   
   
   
2. A list of installed plug-ins will appear.
   
   
3. Locate “Astah AI Chat Copilot” and click [Uninstall].
   
   
4. Restart Astah.
   
   
5. AI Chat Copilot pane no longer appears.