What causes "image prompt is required" in siyuan-note/siyuan?

Validate the prompt at the calling layer (HTTP handler, agent runtime) before invoking Generate, returning a user-facing message.

siyuan-note/siyuan · error

image prompt is required

Error message

image prompt is required

What it means

Thrown by OpenAIImageAdapter.Generate (kernel/util/openai.go:735) when strings.TrimSpace(request.Prompt) is empty. It is the input-contract guard at the very top of Generate and exists because the OpenAI image API rejects empty prompts with a less obvious upstream error; SiYuan fails fast with a clear message instead.

Source

Thrown at kernel/util/openai.go:735

		return "", "", errors.New("generated image is invalid")
	}
	return mimeType, extension, nil
}

func NewOpenAIImageAdapter(apiKey, apiBaseURL, model string, timeout int) *OpenAIImageAdapter {
	if timeout < 1 {
		timeout = 30
	}
	return &OpenAIImageAdapter{
		client:  NewOpenAIClientWithModel(apiKey, apiBaseURL, model),
		model:   model,
		timeout: time.Duration(timeout) * time.Second,
	}
}

func (adapter *OpenAIImageAdapter) Generate(ctx context.Context, request GenerateImageRequest) (GeneratedImage, error) {
	if strings.TrimSpace(request.Prompt) == "" {
		return GeneratedImage{}, errors.New("image prompt is required")
	}
	imageRequest := openai.ImageRequest{
		Prompt:  request.Prompt,
		Model:   adapter.model,
		N:       1,
		Size:    request.Size,
		Quality: request.Quality,
	}
	if strings.HasPrefix(strings.ToLower(adapter.model), "dall-e") {
		imageRequest.ResponseFormat = openai.CreateImageResponseFormatB64JSON
		if imageRequest.Quality == "auto" {
			imageRequest.Quality = ""
		}
	} else {
		imageRequest.OutputFormat = request.OutputFormat
	}
	requestCtx, cancel := context.WithTimeout(ctx, adapter.timeout)
	defer cancel()

View on GitHub (pinned to 251596fc0d)

Solutions

Validate the prompt at the calling layer (HTTP handler, agent runtime) before invoking Generate, returning a user-facing message.
Trim and reject prompt == '' on the UI side so the call is never made.
If an automation pipeline triggers it, audit the prompt construction step.

Example fix

// before
img, err := adapter.Generate(ctx, GenerateImageRequest{Prompt: req.Prompt, Size: req.Size})

// after
prompt := strings.TrimSpace(req.Prompt)
if prompt == "" {
    return nil, errors.New("prompt is required")
}
img, err := adapter.Generate(ctx, GenerateImageRequest{Prompt: prompt, Size: req.Size})

Defensive patterns

Strategy: validation

Validate before calling

prompt := strings.TrimSpace(request.Prompt)
if prompt == "" {
    return errors.New("image prompt is required")
}
request.Prompt = prompt

Try / catch

img, err := adapter.Generate(ctx, request)
if err != nil && err.Error() == "image prompt is required" {
    // surface to user as a form-validation issue, not a system error
    return promptRequiredError{}
}
if err != nil { return err }

Prevention

Trim and reject empty prompts in the HTTP/agent layer before calling Generate.
Disable submit until a non-empty prompt is entered in the UI.
In automation pipelines, assert prompt construction produces non-empty output before dispatch.

When it happens

Trigger: Calling adapter.Generate with a GenerateImageRequest whose Prompt is "", whitespace-only, or accidentally unset (zero value of the struct).

Common situations: Frontend sends the request before the user typed a prompt; an agent/automation pipeline forwards an empty prompt field; a serialization bug drops the prompt key; default struct zero value used unintentionally.

Related errors

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/b03f7677580db928. Report an issue: GitHub.