Ask HN: How do you manage mobile app designs and specifications?

The industry standard for speccing mobile app UI appears to be attempt to precisely spec a full design through visuals, using a tool like Zeplin, and as far as possible describe the app's user facing interactions through annotations.

To me this feels quite inflexible, and isn't always practical in real world situations, when changes to the apps quite often have to be improvised in response to bugs and user feedback.

Does anyone have any experience of a workflow they felt improved on this, or any links to relevant online resources describing alternate approaches?