Exact privileges. No shared accounts.

The matrix is the protocol. public_api is the only role this page assumes. Break-glass is audited and temporary.

Role	Z₁ Ledger	Z₂ Analytics	Z₃ Graph/Model	Z₄ Ontology
curator	INSERT (new) · EXECUTE supersede SP. No UPDATE/DELETE.	Read published snapshots.	No access.	SELECT, INSERT reviewed notes.
evidence_reviewer	SELECT drafts and published.	Read published snapshots.	Read model outputs.	SELECT, UPDATE approval flags.
snapshot_exporter	SELECT approved records only.	WRITE immutable Parquet.	No access.	No access.
analytics_runner	Explicitly revoked.	READ snapshots / WRITE features.	WRITE named projections.	No access.
graph_loader	Explicitly revoked.	READ named projections.	WRITE graph DB.	No access.
model_runner	Explicitly revoked.	READ features.	READ/WRITE embeddings & results.	DENY SELECT. Hard quarantine.
ontology_editor	No access.	No access.	No access.	INSERT/UPDATE hypotheses only.
public_api	SELECT published release views only.	READ released aggregates.	READ approved model outputs.	SELECT with speculative warnings attached.
break_glass_admin	ALL — audited, temporary.	ALL — audited.	ALL — audited.	ALL — audited.

Curator supersession

Direct UPDATE and DELETE on artefacts are revoked. The only write after insert is canonical.supersede_artefact_revision: close the current revision, insert a draft child, write an audit event. That is how the ledger stays a ledger.