Milestone: PIA Synthetic Sandbox Projection Assurance

Date: 2026-07-30

Status: Implemented and validated working checkpoint

Authority: Working/proposed; synthetic-only sandbox boundary remains in force

Commit: To be assigned at the next intentional commit boundary

Builds on: PIA Mapping-to-Output Preview

Overview

This checkpoint validates the first intentionally narrow Neo4j projection path: one embedded synthetic evidence-to-capability assertion written only to the local PIA-Sandbox database. It establishes technical behavior of a guarded sandbox import; it does not authorize projection of protected participant material.

Controls exercised

  • an offline projection-assurance package requires an exact accepted-mapping selection, valid confidence, local_sandbox, PIA-Sandbox, and dry_run;
  • preflight permits only the declared local URI and PIA-Sandbox target;
  • the importer accepts no supplied participant payload and embeds one clearly synthetic row only;
  • an explicit --apply-synthetic action and local Neo4j password are required before a write;
  • malformed, non-synthetic, duplicate, incomplete, or out-of-range package records are rejected before authentication or graph I/O; and
  • read-only post-import validation verifies the run payload and the global cardinality of the evidence node, capability node, mapping relationship, and expected path.

Controlled validation

The synthetic import was executed twice against PIA-Sandbox. The second run was PIA-SANDBOX-RUN-DB739AAD9589. Its read-only validation returned:

Check Result
Run relationship count 1
Synthetic evidence node count 1
Synthetic capability node count 1
Synthetic mapping relationship count 1
Expected evidence-to-capability path count 1
Structural idempotency true

The deliberate invalid-package exercise also passed: an out-of-range confidence was blocked before authentication and reported graph_write: not_performed. The focused protected-intake regression suite passed with 28 tests.

Interpretation and limits

This proves that the bounded synthetic package can be imported, read back, and re-imported without duplicate structural records in the local sandbox. It does not prove production security, participant-data suitability, graph semantics beyond the one synthetic assertion, report publication, or independent review. The sandbox retains only the latest run identifier on the synthetic relationship; it is a technical test marker, not a durable production import audit model.

Remaining gates

  • a governed participant-minimized projection contract and approved target authorization;
  • durable graph import audit, rollback, and exception handling;
  • participant projection deletion and retention semantics;
  • broader graph schema, provenance, and authorization assurance; and
  • controlled-pilot privacy, consent, security, operational, and independent review before any real-participant processing or projection.