Attributes

Attributes are the key-value pairs that appear in an entry’s trailer block — the indented section below the body text. They carry the entry’s identity, type classification, trace links, and any domain-specific metadata declared by the active profile.

Universal attributes

These attributes apply to every entry regardless of type. They are defined by core and are always available, even in core-only mode (no profile configured).

Id

The Id: attribute is the primary stable identifier. Its format determines the entry’s shape:

Id: 01HGW2Q8MNP3RSTVWXYZABCDEF ← Authored (26-char ULID) Id:
urn:iso:std:iso:26262:-6:ed-2 ← Reference (URI with scheme)

ULIDs are assigned by markspec format. An entry without an Id: is “unstamped” — the validator emits MSL-A010 in strict mode, and markspec format will add one on the next run.

Type

The Type: attribute holds the entry’s type name. It may be a core concrete type (Requirement, Test, SoftwareComponent, …) or a profile-declared subtype name (requirement, hazard, feature, …).

Type: requirement

When absent, the toolchain resolves the type through the 8-step chain described in the Type taxonomy chapter. Unknown values raise MSL-T020.

Labels

Labels: is a multi-value attribute. Each value is a free-form tag. The preferred form is one line per tag; CSV is accepted and normalized by markspec format:

# One tag per line (preferred)

    Labels: ASIL-B
    Labels: safety-critical
    Labels: DRAFT

# CSV on a single line (accepted, normalized on format)

    Labels: ASIL-B, safety-critical, DRAFT

Labels are plain strings — they carry no semantics in core. Profiles can declare label concerns (a structured vocabulary of expected labels) and the validator then checks that label values are from the declared set.

References

References: links an entry to an external standard or resource by display ID, optionally followed by a locator in square brackets:

References: ISO-26262-6 [§4.3] References: RFC-2119 [§3] References: serde-1-0

The locator ([§4.3]) is free text — it is preserved verbatim in the compiled output but not parsed further.

External-id

External-id: records a cross-system identifier — the ID of a ticket in an issue tracker, a DOORS object ID, a SharePoint item ID, etc. This is a single-value attribute:

External-id: JIRA-4567 External-id: DOORS-MODULE-23/OBJ-0042

The value is opaque to MarkSpec. It is preserved in the compiled output and available for traceability matrix generation.

Supersedes and Superseded-by

Supersedes: records the display ID of a predecessor entry that this entry replaces. It is only meaningful for Authored entries (external URIs have their own versioning).

Supersedes: SRS_BRK_0042

When markspec format encounters a Supersedes: line, it writes the inverse Superseded-by: attribute on the target entry automatically. The author only writes Supersedes: — never Superseded-by:.

Deprecated

Deprecated: records a retirement reason. The value is a quoted string:

Deprecated: "Replaced by SRS_BRK_0107; no longer relevant after v2.0"

Deprecated entries are not removed — they remain in the compiled output, but the validator can be configured to warn or error on references to deprecated entries.

Multi-value attributes

Any attribute declared as cardinality: multi in the profile accepts one value per line. The two equivalent forms are:

# One value per line (preferred for readability)

    Labels: ASIL-B
    Labels: safety-critical

# CSV (accepted; normalized by markspec format)

    Labels: ASIL-B, safety-critical

markspec format always normalizes to the one-per-line form. If a CSV line contains a value that includes a comma (e.g., a citation locator like ISO-26262-6 [§4, §5]), the square-bracket content is treated as a single token and not split.

Authored-only attributes

Supersedes is only meaningful for Authored entries. Reference entries have stable external URIs as their Id: — versioning happens in the external system, not in MarkSpec.

Reference-only attributes

The following attributes are declared by the @markspec/default profile and apply specifically to Reference-shape entries:

Example:

- [@ISO-26262-6] ISO 26262 Part 6

      Id: urn:iso:std:iso:26262:-6:ed-2
      Reference-document: ISO 26262-6:2018
      Reference-url: https://www.iso.org/standard/68388.html
      License: ISO-proprietary

These attributes are not part of core — they require @markspec/default (or any profile that extends it) to be active. In core-only mode, using Reference-url raises MSL-A020 (unknown attribute key).

Typical attributes by concrete type

The tables below summarize typical attribute usage by type group. Attributes under “Typical profile attributes” are not defined by core — they require the relevant profile to be active. Only the universal attributes in the section above are available in core-only mode.

Specification types

Component types

Unit types

Item types

Profile-declared attributes

A profile can declare additional attributes via its attributes: section:

profile:
  attributes:
    - key: ASIL
      applies-to: [requirement, hazard, test]
      cardinality: single
      values: [ASIL-A, ASIL-B, ASIL-C, ASIL-D, QM]

    - key: Priority
      applies-to: [requirement, change]
      cardinality: single
      values: [critical, high, medium, low]

Profile-declared attributes are validated just like core attributes: unknown values raise MSL-A022, wrong cardinality raises MSL-A013. The difference is that these rules only activate when the declaring profile is present.

Attribute ordering

markspec format normalizes the trailer attribute order:

1. Id
2. Type
3. Relation attributes (Satisfies, Derived-from, Verifies, Tests, …)
4. Labels
5. References
6. External-id
7. Supersedes / Superseded-by
8. Deprecated
9. Any remaining profile-declared attributes (alphabetical)

Attribute order has no semantic significance — the normalized order is purely for readability and diff stability.