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Agent-created Changes remain visual ghosts on a Proposal. They do not mutate the accepted Plan.

Base-version control

Every Proposal names one baseVersion. A stale Proposal is rejected and must be refreshed from a new inspection.

Retry safety

Every mutating command carries an idempotency key. Exact retries return the original Command Receipt; reusing a key with different input is rejected before state changes.

Object Locks

Locks protect position, rotation, dimensions, deletion, or role independently. Venue-template Locks are inherited; only humans can add or release temporary Project Locks. Validation and Proposal conflicts identify the exact Lock. Rejected lock attempts receive an idempotent Command Receipt and a hash-chained Activity Ledger record without changing the Plan.

Warning disposition

Agents cannot create Warning Waivers. A human must select a reason code before Approval; the author, time, Constraint, Proposal, and Validation fingerprint remain in the Activity Ledger and audit export.

Emergency authority

Emergency-affecting Proposals require a separate authorized human Emergency Review before Approval. Reviewer identity, role, accepted assumptions, changed object IDs, base Plan Version, Validation input fingerprint, and emergency evidence fingerprint are committed together; agents cannot supply or bypass this authority.

Traceability

Activity Ledger events are schema-versioned and hash chained. Accepted Plan evidence can be replayed and compared with the current Plan fingerprint; audit export packages the chain, Validation, receipts, branches, and accepted Plan.