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VBL Governance Metadata Fields

Metadata Fields

Section titled “Metadata Fields”

Governance metadata appears at the top of a boundary definition:

boundary_id: payment-authorization
version: 1
scope: production
eta_cap: 9950
Field Purpose Required
boundary_id Unique identifier within the project No
version Version string (informational) No
scope Operational scope No
eta_cap Evidence freshness ceiling No

All metadata fields are optional. At least one must be present for the governance header to exist.

Placement

Section titled “Placement”

Governance metadata must appear first in the boundary definition when present, before evidence requirements, prohibitions, predicates, or the BOUNDARY expression.

boundary_id

Section titled “boundary_id”

A unique identifier for the boundary within its project:

boundary_id: payment-authorization

version

Section titled “version”

A version string. Informational: the platform tracks versions through compiled boundary versions, not this string:

version: 1

scope

Section titled “scope”

The operational scope of the boundary:

scope: production

Metadata Does Not Affect Evaluation

Section titled “Metadata Does Not Affect Evaluation”

Governance metadata is audit and traceability data. It participates in boundary hash computation but does not affect evaluation outcome. The evaluation engine does not interpret metadata values.

Keyword Recognition

Section titled “Keyword Recognition”

Governance keywords (boundary_id, version, scope, eta_cap) are reserved only when immediately followed by :. This ensures backward compatibility: a field named version (without the colon) is a valid evidence field, not a governance declaration.

boundary_id: my-boundary    # governance metadata (keyword + colon)
version: 1                  # governance metadata (keyword + colon)


predicate: check: version_field >= 2   # 'version_field' is an evidence field

Governance keywords are unconditionally excluded from evidence_class_name and predicate_name positions. For example, require_evidence: version is a parse error because version is a governance keyword. However, governance keywords are valid as field names in predicate expressions: predicate: check: version >= 2 is valid because version appears as a field reference, not as an evidence class name.

Next Steps

Section titled “Next Steps”