Vaadin Copilot AI - Error parsing JSON: Unable to write file, JSON chunk that failed

Question

I am testing the Vaadin Copilot AI feature on Windows 11 with Vaadin Flow and asking it to execute the following command:

Create an empty LocationView class with one button on the screen named 'Test'.

And in response, I get an error:

Error parsing JSON: Unable to write file - JSON chunk that failed

Details:

2025-04-02T02:17:19.100+03:00  INFO 32644 --- [ctor-http-nio-7] com.vaadin.copilot.ai.AICommandHandler   : Parsed JSON: StreamResponse[status=VALIDATION, message=Validation finished, exception=, changes={}, code=1]
2025-04-02T02:17:19.757+03:00  INFO 32644 --- [ctor-http-nio-7] com.vaadin.copilot.ai.AICommandHandler   : Parsed JSON: StreamResponse[status=PRE_PROCESS, message=Flow Source modified, exception=, changes={}, code=2]
2025-04-02T02:17:20.478+03:00  INFO 32644 --- [ctor-http-nio-7] com.vaadin.copilot.ai.AICommandHandler   : Parsed JSON: StreamResponse[status=EMBEDDING_CONTEXT, message=Embedding context retrieval finished, exception=, changes={}, code=2]
2025-04-02T02:17:22.617+03:00  INFO 32644 --- [ctor-http-nio-7] com.vaadin.copilot.ai.AICommandHandler   : Parsed JSON: StreamResponse[status=AI_CALL, message=AI call finished, exception=, changes={}, code=2]
2025-04-02T02:17:22.618+03:00  INFO 32644 --- [ctor-http-nio-7] com.vaadin.copilot.ai.AICommandHandler   : Parsed JSON: StreamResponse[status=POST_PROCESS, message=Post-process finished, exception=, changes={src\main\java\ai\example\base\ui\view\LocationView.java=package ai.example.base.ui.view;

import com.vaadin.flow.component.button.Button;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.vaadin.flow.router.Route;

@Route("location")
public class LocationView extends VerticalLayout {

    public LocationView() {
        Button testButton = new Button("Test");
        add(testButton);
    }
}
}, code=2]
2025-04-02T02:17:22.619+03:00  INFO 32644 --- [ctor-http-nio-7] com.vaadin.copilot.ai.AICommandHandler   : PostProcess finished
2025-04-02T02:17:22.620+03:00 ERROR 32644 --- [ctor-http-nio-7] com.vaadin.copilot.ai.AICommandHandler   : Error parsing JSON: Unable to write file (src\main\java\ai\example\base\ui\view\LocationView.java) with data from copilot server response - JSON chunk that failed: {"status":"POST_PROCESS","message":"Post-process finished","exception":"","changes":{"src\\main\\java\\ai\\example\\base\\ui\\view\\LocationView.java":"package ai.example.base.ui.view;\n\nimport com.vaadin.flow.component.button.Button;\nimport com.vaadin.flow.component.orderedlayout.VerticalLayout;\nimport com.vaadin.flow.router.Route;\n\n@Route(\"location\")\npublic class LocationView extends VerticalLayout {\n\n    public LocationView() {\n        Button testButton = new Button(\"Test\");\n        add(testButton);\n    }\n}\n"},"code":2}

What am I doing wrong, and what could be the reason for this?

Answer 1

Vaadin Copilot does not currently support creating new files, and the error message is misleading :(.

It was a somewhat tough decision not to support at the first round to make sure, everything was handled properly from a security perspective.

There is already work, and PR to change this and support creating the file, so when this PR is merged and the new copilot client (Vaadin framework) is released, probably this will be changed, and you can do this without any issues.

If you have any other problem or idea, please continue raising it here on stackoverflow, or even in the relevant repository. It is listened to and concerned, and it is super helpful!

Thank you very much alexanoid.