probe.rs is a standalone executable using the unchanged shared core. It writes three deterministic complete model/source snapshots under a supplied directory. There is no proposed DTO implemented in this helper and no native input.

Observed result, 2026-09-06:

Valid baseline:12 elements/5 relations, one System/Actor pair, two Standard ports, one boundary/interface, two Synchronous parameterless Operation items, two participant lifelines and two Calls.
Both Calls' typed bodies are identical. Their names express different intent; neither Call references its intended item/allocation identity.
Using item or allocation as the existing exchange reference rejects with occurrence_exchange; adding an operation field to the typed JSON rejects as unknown. No undiscovered existing selector is being relabeled missing.
Renaming then deleting Reset preserves the Call body and leaves the Call structurally valid, because there is no maintained operation-use reference.
Explicit functional refinement distinguishes the two messages and preserves the same boundary, but adds6 elements (two Functions/four ports) and10 relationships. It is a real alternative when that refinement is intended, not a zero-cost encoding of the unrefined interface-only model.
All three output models pass complete source and JSON round trips. No core or desktop production file was changed.

The first helper compile lacked explicit validation imports; initial construction also used the disabled generic Port factory and reversed Allocation/PortAllocation directions. Those helper errors were corrected before the successful full run. They are not product defects. Final compilation used -D warnings and succeeded.

Reproduce only after coordinating stable rlibs/shared resources:

. .local/toolchain/env.ps1
rustc --edition 2024 -D warnings -C linker=clang.exe --extern oa_core=.local/target-gnullvm/debug/deps/liboa_core-6c8da57367eec642.rlib --extern serde_json=.local/target-gnullvm/debug/deps/libserde_json-da2c4f333fc47818.rlib -L dependency=.local/target-gnullvm/debug/deps harness/fixtures/interface-operation-probe/probe.rs -o .local/native-fixtures/interface-operation-probe.exe
.local/native-fixtures/interface-operation-probe.exe NEW_OUTPUT_DIRECTORY

Final output is retained in .local/native-fixtures/interface-operation-probe.log. The tracked output/ files are probe oracles, not native acceptance fixtures. See the proposed contract.