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Supported Inputs

Supported Inputs explains what you can add before creating a Project, and how Castaly treats each kind of material. Good input gives Castaly a clearer first understanding, but you do not need a complete brief to begin.

Text

A short idea, product brief, pasted notes, requirements, or instructions. Pasted links are kept as text context; Castaly does not fetch the page behind them.

Images

Screenshots, visual references, UI examples, or multiple images that show the experience you want Castaly to understand.

Files

Documents that contain requirements, product context, copy, flows, or constraints. Castaly reads them as supporting material for the first Spec.

TypeFormatsLimit
ImagesPNG, JPG / JPEG, WEBPUp to 8, max 10 MB each
FilesPDF, Markdown (.md), TXT, HTMLUp to 5, max 20 MB each

Add images and files by pasting, dragging them onto the composer, or using the + menu. Unsupported files, unsupported formats, and files over the limit are rejected before they attach, with a short message explaining what needs to change.

The two starting modes do not change what you can add. They change which input Castaly treats as the primary source.

Start from an Idea

Choose this when you can describe the result you want. Text leads; images and files provide additional context.

Start from a Reference

Choose this when screenshots, prototypes, or documents are the main thing Castaly should follow. Text adds instructions, constraints, or changes you want.

If the reference is the thing you want Castaly to follow, use Start from a Reference. If your written direction is the source of truth, use Start from an Idea. See Create a Project for where these modes appear in the composer.

These inputs are not part of the current experience:

URL capture

Castaly does not fetch, crawl, or inspect live web pages. If you paste a URL, it remains plain text context.

ZIP upload

Archives cannot be uploaded. Add the individual images and documents instead.

Repo import

Code repository import is not available. Castaly starts from your description, references, and documents.

Next: Project Workspace Overview explains what you see after a Project opens.