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A predicate names what a claim means. In Mara works_at Northstar Labs, the predicate is works_at. Relationships use it as rel_type; attributes use it as attr_type. The registry gives a space a canonical vocabulary. Its aliases connect source wording such as “employed by” to that vocabulary. Its semantics describe how claims behave over time and whether multiple values can be valid together.

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Vocabulary and semantics are separate

Registering a predicate does not settle its semantics. The MCP register_predicate operation stores an active registry entry with semantics: null and semantics_status: default. For example, its arguments can be:
The tool registers vocabulary. The current public HTTP and MCP registration surfaces do not accept an arbitrary semantics object or expose a general semantics-update operation. Explicit operator configuration requires a controlled administrative integration with the registry. The REST create handler retains one special case for the exact predicate has title; do not assume that behavior applies to arbitrary predicates or to MCP registration.

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Choose semantics from the domain

The meaning of a predicate determines whether two values contradict each other. Two languages a person speaks can coexist. Two different values for a single-valued identifier need examination. Employment may permit concurrent roles, so works_at should not automatically be configured as single-valued for every application. The default semantics object permits many values with allow_parallel and a promotion threshold of 0.7. An absent semantics object still means the predicate is unconfigured. In particular, truth maintenance examines unknown cardinality for possible cross-object conflicts rather than assuming it has been deliberately configured as many.

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Review status records who supplied the policy

When a real conflict has unknown semantics, the configured LLM adjudicator can propose them. A proposal cannot overwrite operator-configured semantics. Later adjudications can revise non-configured proposals. Registry changes emit an outbox event so dependent truth slots can recompute. An LLM proposal is useful evidence for review, rather than equivalent to operator configuration. The Living Wiki’s governed graph context requires explicitly configured predicate semantics before those graph claims can contribute to an article.

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Govern aliases

An alias record maps a raw string, plugin code, or schema field to a canonical predicate. Its status can be proposed, active, or deprecated. The pipeline proposal workflow stages a work_artifact. The MCP tools validate_predicate_proposal and approve_predicate_proposal consume that artifact’s ID; an unvalidated artifact cannot be approved. The similarly named propose_predicate_alias tool creates a PredicateAlias row with status proposed. Its returned alias ID is not a proposal artifact ID and cannot be passed to the artifact validation tools. The HTTP alias status operation is the separate surface for activating or deprecating an alias row. Aliases also have scopes: Here global does not grant cross-space access. Record space and security checks continue to apply. Alias thresholds distinguish weak query assistance from canonical truth. The default query_expand_min_confidence is 0.6; the default truth_min_confidence is 0.9. A useful search synonym is not automatically strong enough to rewrite a canonical claim.

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Avoid semantic surprises

  • Review cardinality before interpreting every different object as a conflict.
  • Keep raw wording in assertions so a canonicalization decision remains auditable.
  • Treat a semantics update as a change that can make existing truth slots stale.
  • Do not infer operator approval from an active registry entry or an LLM proposal.

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Next steps