Anthropic built a tool that checks whether Claude created image files by reading cryptographically signed metadata attached to downloads, using the C2PA industry standard that camera makers and photo software already use. Text detection works differently and requires a separate API currently available only to certain EU organizations.

• Claude embeds content credentials (signed metadata) in supported file types like PNG, JPG, and SVG to prove involvement in creation or processing
• The checker only reads the embedded credential, not the file itself, and never stores or accesses your uploaded file
• Text watermark detection uses a separate API in private preview, while similar file-checking tools exist from OpenAI and Google DeepMind