#DFOS Content Model

Standard content schemas for documents committed to DFOS content chains. JSON Schema (draft 2020-12) definitions for what goes inside the document envelope's content field.

These schemas are conventions, not protocol requirements. The DFOS Protocol commits to documents by CID without inspecting their contents — any valid JSON object with a $schema field can be committed. The content model defines the vocabulary that DFOS uses internally, provided as a starting point for applications built on the protocol.

Protocol Specification · schemas.dfos.com · Source

#Schema Convention

Every document committed to a content chain is wrapped in a document envelope. The envelope's content field holds the application-defined payload. The protocol requires one thing of this payload: it must include a $schema property identifying its content type.

{
  "$schema": "https://schemas.dfos.com/post/v1",
  "format": "short-post",
  "body": "Hello world."
}

Because $schema is part of the document, it is behind the documentCID — cryptographically committed in the content chain. Any verifier can resolve the document, read $schema, and validate against the schema. Documents are self-describing.

#Schema Evolution

Schemas are versioned via the URI path (/post/v1, /post/v2). Evolution rules:

• Strictly additive within a version — new optional fields can be added to an existing version at any time without breaking existing documents
• Breaking changes require a new version — removing fields, changing types, or adding new required fields means a new version URI
• Implementations declare which versions they understand — a registry or application can accept post/v1 and post/v2 simultaneously, or only post/v1

#Standard Schemas

Schema files live in schemas/ in the protocol package. Each is a standalone JSON Schema (draft 2020-12) definition, served at https://schemas.dfos.com.

#Post (https://schemas.dfos.com/post/v1)

The primary content type. Covers short posts, long-form posts, comments, and replies via the format discriminator.

#Profile (https://schemas.dfos.com/profile/v1)

The displayable identity for any agent, person, group, or space.

#Media Object

Several schemas reference media objects. The standard representation:

{
  "id": "media_abc123",
  "uri": "https://cdn.example.com/media/abc123.jpg"
}

id is required (opaque identifier). uri is optional.

#Chain Interpretation

A content chain is a signed append-only log. The protocol enforces ordering, authorship, and integrity. It does not prescribe what the chain means. How an application interprets a content chain depends on the content types committed to it.

#Living Document

The chain represents a single evolving thing — a profile, a post, a policy document. Each operation is a revision. The resolved state is the latest documentCID. History is audit trail. The content is the current version.

This is the default interpretation for the standard schemas. The document envelope's baseDocumentCID field supports edit lineage — each new document version can point back to the one it replaced.

#Stream

The chain represents a sequence — a feed, a journal, a log. Each operation is a discrete emission, not a revision. There is no single "current state" — the chain is the content. Previous documents aren't superseded, they're siblings in a series.

#Other Patterns

The protocol cannot distinguish these patterns — the operation schema is identical in both cases. The difference is a reading convention, signaled by the $schema of the documents. Future content types could define event-sourcing patterns, append-only collections, or interpretations not yet imagined.

#Custom Schemas

Any implementation can define custom document schemas following the same pattern — a JSON Schema with a $schema const field pointing to a unique URI. The protocol will commit to the document via CID regardless of what's inside. The standard schemas are conventions, not constraints.

Custom schema URIs should use a namespace you control (e.g., https://schemas.example.com/my-type/v1) to avoid collisions with the standard library.