Cerebro Rust Migration

Cerebro Rust Migration

Authority cutover is family-by-family and fails closed. Before editing, read docs/engineering/rust-organizational-platform.md (authority model, compatibility port, remaining-callers table) and docs/engineering/rust-graph-read-migration-plan.md (sequencing and capability gaps).

Invariants that gate every change

• A persisted (tenant, source, family) authority record selects exactly one writer, including replay/refetch/device/CLI/orchestrator entry points. Do not add alternate Go entry points that could restore a retired writer.
• Rust authority requires a commit receipt and fails closed. The compatibility mapper is parity evidence, never a write fallback for a promoted family.
• Promotion is driven by stored parity receipts: cerebro-platform evaluate-family evaluates, promote-family records authority, show-authority reads the effective record.

Porting a compatibility caller

1. Find the caller's row in the remaining-callers table; it names the exact Rust read-API capability gap blocking it.
2. Map the caller's entity kinds and relations into the organizational schema before touching query code; path callers additionally need URN-keyed FindPaths entry points.
3. Migrated callers must stop referencing ports.RawCypherQueryStore — that reference is what marks a caller as legacy.
4. Update the remaining-callers table in the same PR.

Parity and validation

• make fixture-oracle-generate regenerates the checked Go fixture oracle consumed by Rust parity tests.
• make projection-parity-test compares legacy and Rust semantic projection facts over the same provider records.
• Focused Rust loop: make rust-fmt-check rust-clippy rust-test; benchmarks via make rust-organizational-platform-benchmark when projection cost is touched.
• make changed-check for the diff-selected remainder.

Public PR safety

Keep tenant names, environment details, candidate counts, and rollout observations out of public PR metadata — see "Public PR Data Safety" in AGENTS.md.