Interface LegacyFormatReferenceStructuredObject

URL of the agent that defines this format (e.g., 'https://creative.adcontextprotocol.org' for standard formats, or 'https://publisher.com/.well-known/adcp/sales' for custom formats). Callers comparing two format-id values MUST canonicalize agent_url per the AdCP URL canonicalization rules before treating two formats as the same. See docs/reference/url-canonicalization.

Format identifier within the agent's namespace (e.g., 'display_static', 'video_hosted', 'audio_standard'). When used alone, references a template format. When combined with dimension/duration fields, creates a parameterized format ID for a specific variant.

Width in pixels for visual formats. When specified, height must also be specified. Both fields together create a parameterized format ID for dimension-specific variants.

Height in pixels for visual formats. When specified, width must also be specified. Both fields together create a parameterized format ID for dimension-specific variants.

Duration in milliseconds for time-based formats (video, audio). When specified, creates a parameterized format ID. Omit to reference a template format without parameters.

Required intrinsic-pixel density for a parameterized visual format, expressed as intrinsic pixels per logical pixel. Requires width and height. Example: {id: "display_image", width: 300, height: 250, pixel_ratio: 2} identifies a 300×250 logical render supplied by a 600×500 image. Omit for the backward-compatible 1x variant.