SDT YAML-in-HTML: HTML Container Attributes

Part of the WebMEM Protocol
Location: /specification/sdt/yaml-in-html/attributes/
Last Updated: 2025-07-28

HTML Container Attribute Reference

The <template> element serves as the outer container for every Semantic Data Template (SDT) fragment. To support agentic discovery, DOM parsing, and metadata extraction, a specific set of data-* attributes are used to encode fragment-level identity, class, and scope.

Required Attributes

Attribute	Description
`data-visibility-fragment`	Declares the template as an SDT fragment. Required on all fragments.
`data-type="text/yaml"`	Signals the format of the template body (YAML-in-HTML). Required.
`data-sdt-class`	The SDT fragment class (e.g., `DataFragment`, `FAQFragment`). Must match the `data-sdt-class:` in the YAML body.
`data-entity`	Defines the real-world subject the fragment describes (e.g., `plan:H5521-290-0`). Required for entity-scoped classes like `DataFragment`, `DefinedTermFragment`, etc.
`data-digest`	Declares the digest group this fragment belongs to. Used for retrieval, export, and clustering.
`data-fragment-scope`	Declares the publishing domain or retrieval layer (e.g., `semantic-digest`, `gtp`). Enables AI agents to cluster fragments by trust layer.

Example Usage of data-fragment-scope

<template data-fragment-scope="sdt-core-protocols">

Recommended Attributes

Attribute	Description
`data-glossary-scope`	Namespace governing `glossary:` and `related_terms:` inside YAML. Strongly recommended.
`data-fragment-id`	Canonical ID for internal references, citation anchoring, and export metadata. Optional if `id="..."` is resolvable.

Note: All data-* values must match their equivalents in the YAML fragment header.

Reserved ID Conventions

The id attribute on <template> and <div> plays a crucial role in linking, citation, and trust propagation.

Reserved Patterns

Pattern	Applies To	Purpose
`id="provenance-meta"`	`<div>` or YAML block	Declares the ProvenanceMeta trust anchor. Must be unique per page.
`id="fragment-*"`	`<template>`	Standard prefix for SDT containers. Required for machine-resolution and export.

Examples

<!-- SDT Fragment -->
<template id="fragment-h5521-290-0-primary-care" ... >

<!-- Provenance Block -->
<div id="provenance-meta" ... >

Best Practices

Prefix all SDT containers with fragment-
Never reuse fragment IDs across entities or digests
Only use provenance-meta once unless composing for multiple children