Content Access Capability¶

Capability Name: dev.ucap.content.access

The primary capability — fetching content with automatic entitlement verification. When an agent requests content, the server checks the agent's entitlements and returns either the full content (200) or subscription offers (402).

Endpoints¶

Method	Path	Description
`GET`	`/v1/content/{publisher_id}/{post_id}`	Fetch content by publisher and post ID
`GET`	`/v1/content?url={original_url}`	Fetch content by original URL

Operations¶

Fetch Content¶

Retrieve a single piece of content. The server verifies the agent's identity and entitlements before returning the content.

RequestResponse (200 — Entitled)Response (402 — Payment Required)

GET /v1/content/{publisher_id}/{post_id} HTTP/1.1
Host: api.example.com
Signature-Agent: {agent_id}
Signature: sig=:{base64_signature}:
Signature-Input: sig=("@method" "@path" "host" "date");keyid="{agent_id}"
Date: Wed, 04 Feb 2026 12:00:00 GMT
UCAP-Purpose: read
Authorization: Bearer {user_token}

The Authorization header is OPTIONAL — it is only required for identity-linked requests where an agent acts on behalf of a specific user.

{
  "content": {
    "html": "<article>Full post content...</article>",
    "text": "Plain text version...",
    "format": "html"
  },
  "metadata": {
    "id": "post-123",
    "title": "Premium Article Title",
    "author": "Creator Name",
    "published_at": "2026-02-01T10:00:00Z",
    "updated_at": "2026-02-02T15:30:00Z",
    "tier": "premium",
    "word_count": 2500,
    "reading_time_minutes": 10
  },
  "publisher": {
    "id": "my-newsletter",
    "name": "My Newsletter",
    "url": "https://example.com/my-newsletter"
  },
  "attribution": {
    "required": true,
    "format": "Source: [My Newsletter](https://example.com/my-newsletter/post-123)"
  }
}

{
  "error": {
    "code": "payment_required",
    "message": "This content requires a subscription"
  },
  "teaser": {
    "title": "Premium Article Title",
    "excerpt": "First 200 characters of the article...",
    "text": "The leaked GPT-5 benchmarks reveal significant jumps in reasoning, code generation, and multi-step planning. In this deep dive, we analyze what the numbers actually mean, compare them to Claude 4 and Gemini Ultra, and explore what this signals for the broader AI industry...",
    "word_count": 150,
    "format": "text",
    "author": "Creator Name",
    "published_at": "2026-02-01T10:00:00Z"
  },
  "offers": [
    {
      "tier_id": "premium",
      "tier_name": "Premium",
      "price": {
        "amount": 1500,
        "currency": "USD",
        "interval": "month"
      },
      "features": [
        "Full access to all premium posts",
        "Early access to new content"
      ],
      "checkout_url": "https://example.com/checkout/session_abc123"
    },
    {
      "tier_id": "supporter",
      "tier_name": "Supporter",
      "price": {
        "amount": 500,
        "currency": "USD",
        "interval": "month"
      },
      "features": [
        "Access to members-only posts"
      ],
      "checkout_url": "https://example.com/checkout/session_def456"
    }
  ],
  "publisher": {
    "id": "my-newsletter",
    "name": "My Newsletter"
  }
}

Response Fields¶

Content Object¶

Field	Type	Description
`html`	string	Full content in HTML format
`text`	string	Plain text version of the content
`format`	string	Content format (`html`, `markdown`, `text`)

Metadata Object¶

Field	Type	Description
`id`	string	Post identifier
`title`	string	Post title
`author`	string	Author name
`published_at`	string	Publication timestamp (RFC 3339)
`updated_at`	string	Last update timestamp (RFC 3339)
`tier`	string	Content tier ID
`word_count`	integer	Content word count
`reading_time_minutes`	integer	Estimated reading time in minutes

Attribution Object¶

Field	Type	Description
`required`	boolean	Whether attribution is required
`license`	string	Content license (e.g., `CC-BY-4.0`)
`format`	string	Suggested attribution format string

Teaser Object (402 Response)¶

Field	Type	Description
`title`	string	Post title
`excerpt`	string	Short preview blurb (1–2 sentences)
`text`	string	Publisher-authored preview content (see Teasers)
`word_count`	integer	Number of words in the teaser text
`format`	string	Teaser text format: `text`, `html`, `markdown`
`author`	string	Author name
`published_at`	string	Publication timestamp (RFC 3339)

The text field provides a substantial publisher-authored preview that gives agents enough context to evaluate the content's relevance. See Publisher Teasers for details on how publishers configure teasers.

Offer Object (402 Response)¶

Field	Type	Description
`tier_id`	string	Subscription tier identifier
`tier_name`	string	Human-readable tier name
`price`	object	Price with `amount` (cents), `currency`, `interval`
`features`	string[]	List of tier features
`checkout_url`	string	URL for the human to complete payment

Status Codes¶

Status	Meaning
`200 OK`	Content returned — agent is entitled
`402 Payment Required`	Subscription needed — offers returned
`403 Forbidden`	Agent not authenticated or invalid signature
`404 Not Found`	Post does not exist
`429 Too Many Requests`	Rate limit exceeded

Guidelines¶

For UCAP Servers¶

Servers MUST verify HTTP Message Signatures (RFC 9421) before returning content
Servers MUST return 402 with at least one offer for paywalled content
Servers SHOULD include a teaser with title, excerpt, and publisher-authored preview text in 402 responses
Servers SHOULD include attribution requirements in 200 responses
Servers MAY support content access by original URL via the ?url= query parameter

For Agents¶

Agents MUST sign all requests per RFC 9421
Agents MUST handle 402 responses gracefully
Agents MUST present checkout URLs to humans — not auto-purchase
Agents SHOULD include the UCAP-Purpose header
Agents SHOULD respect attribution requirements when displaying content