Oneshot isolation — contract gate verification

Historical verification of a removed tree

This record described a fix in the vendored Hermes snapshot. That snapshot was deleted in PR #377 (3ebde2dd). It is not a current operating contract; see the vendor-fate record. The reconciled regression module named below may still exist; the source path it originally guarded does not.

Verification record for the hermes -z one-shot session-isolation area after the stale characterization tests were reconciled with the applied fix. This document captures the operational evidence that the repository contract gate is green for this area, complementing the automated regression module tests/test_hermes_oneshot_session_isolation.py.

Scope

The one-shot path (hermes -z) must run in a clean, isolated state instead of inheriting persistent session context. The applied fix lives in src/mac/_hermes/hermes_cli/oneshot.py: _run_agent() constructs AIAgent(...) with skip_memory=True and skip_context_files=True, so a one-shot run never loads persistent MEMORY.md / USER.md or repo context files. The session store wiring is unchanged (_create_session_db_for_oneshot() still opens the default state.db under HERMES_HOME); isolation is enforced by the agent not requesting persistent memory, not by repointing the store.

What was verified

Check	How	Result
Reconciled module (bare)	pytest tests/test_hermes_oneshot_session_isolation.py	9 passed
Reconciled module (hermetic gate)	scripts/run-contract-tests.sh tests/...isolation.py -v	9 passed, 0 skipped
Full contract gate	scripts/run-contract-tests.sh	green, exit 0
Coverage floors	statement/branch floor policy	met

The hermetic gate scrubs HERMES_* / MAC_*/ GH_TOKEN and redirects HOME to a throwaway directory, so passing there — not just under a bare pytest — is the meaningful signal. The reconciled module reports no skips under the gate: the runtime TestOneshotMemoryIsolation class is guarded by a SNAPSHOT_PIN skipif that correctly runs when the vendored Hermes snapshot is present.

Gate summary

bulk phase:      8667 passed, 4 skipped
protected phase: 4 passed, 39 skipped, 8671 deselected
coverage:        statements 90.88% (floor 90.00%), branches 80.26% (floor 80.00%)

No failures were attributable to the reconciled test module or the one-shot isolation area. No source change to the fix was required — it is already applied in src/mac/_hermes/hermes_cli/oneshot.py — so this record and the reconciled regression module are the tracked deliverables for the gate.