Catalog Capability¶

The Catalog capability enables agents to discover publishers and search content before accessing it. This fills the "discovery gap" — while Content Access assumes you already have a post ID, the Catalog enables scenarios like "find me AI newsletters under $10/month" that lead to subscription and access.

Following UCP's catalog pattern, UCAP splits the catalog into two independent capabilities that implementers can adopt separately:

Capability	ID	Description
Catalog Search	`dev.ucap.content.catalog.search`	Free-text search with filters and pagination
Catalog Lookup	`dev.ucap.content.catalog.lookup`	Direct lookup by publication or post ID

Motivation¶

Without a standardized catalog interface:

Agents cannot discover what content is available
Every integration requires custom discovery mechanisms
There's no way to search across multiple publishers

Data Structures¶

Publication¶

A publication represents a publisher's content collection (analogous to UCP's Product).

Field	Type	Description
`id`	string	Unique publication identifier
`slug`	string	URL-friendly identifier
`title`	string	Publication name
`description`	string	Publisher description
`url`	string	Canonical URL
`category`	string	Primary category
`price`	PriceRange	Price range (min/max across tiers)
`media[]`	array	Images, logos (first = featured)
`tiers[]`	array	Subscription options (first = featured)
`rating`	object	Aggregate agent ratings (optional)
`post_count`	integer	Total posts available
`language`	string	Primary content language (BCP 47)
`metadata`	object	Publisher-defined extensions

Post¶

A post represents a single piece of content (analogous to UCP's Variant).

Field	Type	Description
`id`	string	Post identifier (used as `post_id` in content access)
`external_id`	string	Source platform ID (e.g., Patreon post ID)
`title`	string	Post title
`excerpt`	string	Preview text
`published_at`	string	Publication timestamp (RFC 3339)
`min_tier`	string	Minimum tier required for access
`category`	string/array	Post category or tags
`media[]`	array	Featured images
`word_count`	integer	Content length
`reading_time_minutes`	integer	Estimated read time
`metadata`	object	Post-specific extensions

Context Object¶

The context object allows agents to specify preferences that affect search and display.

{
  "context": {
    "language": "en",
    "currency": "USD",
    "country": "US",
    "intent": "research on AI agent architectures"
  }
}

Field	Type	Description	Example
`language`	string	Preferred content language (BCP 47)	`"en"`, `"es"`, `"fr-CA"`
`currency`	string	Preferred price display currency (ISO 4217)	`"USD"`, `"EUR"`
`country`	string	Agent's operating region (ISO 3166-1 alpha-2)	`"US"`, `"GB"`
`intent`	string	Semantic description of search goal	`"find weekly AI newsletters"`

Extensions¶

The catalog capability is designed for extension. Publishers and platforms can add domain-specific fields via the metadata object without protocol changes.

Planned Extensions¶

Extension	Capability ID	Description
Topics	`dev.ucap.content.catalog.topics`	Detailed topic/tag taxonomy
Freshness	`dev.ucap.content.catalog.freshness`	Content recency signals
Ratings	`dev.ucap.content.catalog.ratings`	Agent ratings and reviews
Recommendations	`dev.ucap.content.catalog.recommendations`	Personalized suggestions