ARCADIA-Studio/harness/experiments/placement-clearance-20260925/result-review.md

Independent clearance experiment result review

Primary evidence is explicit-UTF8 placement-clearance-20260925/run02, source074051261a0beee1047e2b5624c879deef7813bc. Read-only analysis of recorded Projects/geometry/receipts; no compiler, router, engine or GUI run. The bounded repair resolves the exact sparse terminal incompatibility, but the result is not a general connection-aware Arrange solution or a quality winner. It remains flat-only and worsens several tracing metrics.

Admission and corpus integrity

Independently verified every run02 bound input's current SHA against inputs_after, exact inputs_before/after equality, all18 process receipts (17 candidate cases plus routing control) exit0/not timed out, and stdout/stderr hashes. Routing-control bytes equal the frozen released-router geometry file for all five original cases. These observations support the narrow no-output-change routing refactor claim for that corpus, not all possible graphs.

All12 generated seed Projects exactly equal the corresponding prior UTF8-decoded Projects, recursively without float tolerance. Original corpus files remain hash bound. Run01 is preserved and superseded: nine generated mixed/sparse seeds were exact, but three workshop seeds each changed27 string leaves (81 total). Every change is exactly the result of decoding original UTF8 bytes as cp1252; numeric geometry and structure were unchanged. Full paths and values are in placement-clearance-run01-seed-audit-20260925.json. Corrected run02 removes those seed changes. This is runner encoding failure, not model mutation by the Rust candidate.

All17 cases accounted for

• Unsupported5: workshop original's original/reset/layered placements, and folded workshop original/reset. Each explicitly reports nested/folded/omitted placements unsupported. No successful hierarchy result is inferred.
• Supported12: four original/reset/layered/ELK placements for each of mixed dispatch, its relation-ID permutation, and sparse40.
• Eleven supported cases have no node movement. Sparse40 ELK alone moves8 stored node positions by exactly(0,+11), changes23 projected port positions and zero port sides.

For every supported case, independently reconstructed the entire expected raw Project from before: substitute only returned node positions and clear waypoints/full label only for visible flat edge route entries. Complete object equality with after proves preserved stored sizes, all node metadata/anchors, semantic records, other diagrams, route entry/order/attachments and unrelated fields. Verified exact stored/projected node identity scope, flat/unfolded topology, complete (owner,element) port key sets without duplicates, and exact projected-edge identities/semantics. This does not rely on the emitted conservation booleans. All12 recorded same-input repeats and9 subsequent repair calls report exact equality; both recorded JSON and source roundtrips are exact. These are assertions from the frozen executable output, not independently rerun commands.

Independent geometry agreement

Applied the preexisting independent segment interval/contact evaluator to all24 before/after supported scenes. All96 comparisons agree within0.001 for proper crossings, unique pairwise contacts, common physical terminal contacts and raw pairwise shared length. Independently intersected every unrelated routed stroke with flat node interiors and every node pair in all24 scenes; penetration and overlap counts agree. Full results and source receipt binding are retained in placement-clearance-run02-independent-audit-20260925.json.

Sparse ELK changes:

Metric	Before	After
NoClearPath warnings	1	0
Unrelated node penetrations	1	0
Unrelated node overlaps	0	0
Proper crossings	20	22
Point contacts	55	58
Pairwise shared length	666	761
Label/stroke intersections	0	1
Total route length	64223	64322
Drawing area	12840450	12936535

The shared/crossing/contact/penetration numbers above have independent arithmetic corroboration. Label/stroke, length and area are emitted metric observations; the new label/stroke witness is explicitly identified below. No count establishes glyph readability or navigation usability.

Exact repaired witness

Assessment Package remains x4522..4746,y660..820. Planning Aggregate moves from top840 to851 with unchanged stored/projected size224×160. Its top port is now(4634,851), outward18-unit stub(4634,833). The blocker inflation ends at832: the planned one-unit margin is realized exactly. Independently checked all110 semantic-port terminal leads in the final sparse scene against all40 inflated rectangles: zero unrelated lead intersections and zero stub-containing obstacles.

Flow_45 ...03347d now follows (4120,477)→(4120,495)→(4377,495)→(4377,833)→(4634,833)→(4634,851). The recorded prior160-unit unrelated-node penetration is absent under independent interval tests. This validates the local spacing hypothesis without changing port sides, authored anchors, or adopting raw ELK bends.

A new recorded label/stroke intersection remains: flow_45 crosses the label of edge ...03347a, emitted interior intersection length23.9998. Thus the former hard terminal failure has been traded for additional route contacts/crossings/sharing and a new label interference. The test is a useful capability witness, not adoption evidence.

Decision and limitations

Accept the evidence that final-projection lead compatibility is a useful placement constraint and that this bounded flat repair can solve the named mismatch. Do not adopt the repair as the user-facing Arrange planner: five hierarchy cases are unsupported, supported no-op cases retain their prior quality limitations, and sparse quality is non-dominating. Do not retune this frozen experiment to erase the tradeoff. The next implementation decision belongs in connection-aware placement/coordinate assignment with shared lead constraints and actual reprojection; production selection/history integration and native trace tasks remain untested here.

The diagnostic is necessary-only, and the independent final sparse clearance check does not imply every graph admits a route. No performance, glyph measurement, native usability, production acceptance or remote publication claim is made.

• placement-clearance-run02-independent-audit-20260925.json SHA256 ec5094c81dc4f200ec53d01fb0dca9efd0ce71338922043f5a18a3d409a46c10.

• placement-clearance-run01-seed-audit-20260925.json SHA256 f3785e637284923e87e55243436c2b45a1f101fb059d69d8a71b5f0def8380ea.

• receipt.json SHA256 ea2eeea0e09d9588a5c1a025c058455fa984f46d17a154f08ec4d328732cc1ee.