Comfy-Org/ComfyUI · error · ValueError

One of prompt or structured_prompt is required to be non-emp

Error message

One of prompt or structured_prompt is required to be non-empty.

What it means

Bria's image edit endpoint requires editing instructions: the node sends instruction (prompt) or structured_instruction (structured_prompt) and refuses to call the API when both are empty strings, since Bria would have nothing to act on.

Source

Thrown at comfy_api_nodes/nodes_bria.py:158

            ),
        )

    @classmethod
    async def execute(
        cls,
        model: str,
        image: Input.Image,
        prompt: str,
        negative_prompt: str,
        structured_prompt: str,
        seed: int,
        guidance_scale: float,
        steps: int,
        moderation: InputModerationSettings,
        mask: Input.Image | None = None,
    ) -> IO.NodeOutput:
        if not prompt and not structured_prompt:
            raise ValueError("One of prompt or structured_prompt is required to be non-empty.")
        mask_url = None
        if mask is not None:
            mask_url = await upload_image_to_comfyapi(cls, convert_mask_to_image(mask), wait_label="Uploading mask")
        response = await sync_op(
            cls,
            ApiEndpoint(path="proxy/bria/v2/image/edit", method="POST"),
            data=BriaEditImageRequest(
                instruction=prompt if prompt else None,
                structured_instruction=structured_prompt if structured_prompt else None,
                images=[await upload_image_to_comfyapi(cls, image, wait_label="Uploading image")],
                mask=mask_url,
                negative_prompt=negative_prompt if negative_prompt else None,
                guidance_scale=guidance_scale,
                seed=seed,
                model_version=model,
                steps_num=steps,
                prompt_content_moderation=moderation.get("prompt_content_moderation", False),
                visual_input_content_moderation=moderation.get("visual_input_moderation", False),

View on GitHub (pinned to 1c6d8d45b3)

Solutions

1. Type a non-empty prompt describing the edit.
2. Or fill structured_prompt (Bria's structured instruction format) if you prefer machine-readable instructions.
3. If driving the node programmatically, assert at least one of the two strings is truthy before queueing the prompt.

Example fix

// before
prompt = ''
structured_prompt = ''
// after
prompt = 'remove the background and add a beach'

if not prompt.strip() and not structured_prompt.strip():
    raise UserError('Fill prompt or structured_prompt before running Bria edit.')

When it happens

Trigger: Calling BriaEditImage.execute with prompt == '' and structured_prompt == '' (both widgets blank).

Common situations: User relies on the input image alone and leaves prompt empty; prompt text was in a variable that evaluated to empty/whitespace-only; frontend widget defaulted to empty string.

Related errors

• Connect at least one keyframe image.
• Spreading {len(images)} images across the clip needs an expl
• The mask is empty, so there is nothing to {action}. Masks ar
• Mask must have the same aspect ratio as the image: image is
• Bria accepts a width-to-height ratio between {BRIA_MIN_RATIO

AI-assisted analysis of Comfy-Org/ComfyUI@1c6d8d45b3 (2026-08-14). Data as JSON: /api/errors/8c0bfaa52df50939. Report an issue: GitHub.