fix(agent): content-transition file mutation verifier clears stale footers

[rille111]

Summary

• Add TurnFileMutationVerifier (content-transition contract): pre-dispatch baselines, local bounded observation, fail-closed reconciliation, and sanitized turn-end footers.
• Wire verifier through tool executor (dispatch tri-state, write_file/patch barriers), turn context/finalizer, and run_agent legacy sync.
• Tests cover content-transition suppression, unchanged-file retention, V4A parser parity, path safety, and batch segmentation barriers.

Test plan

• pytest verifier + redesign + segmentation + dispatch helpers (118 passed locally)
• scripts/run_tests.sh full matrix on CI/Linux devShell
• Manual: failed patch then terminal edits same file — footer should clear when content safely observed to change

Notes

Rebased onto current main. The PR is exactly 3 verifier commits (8064355, fb37c82, 64b7e60), no inherited fork history.
Remaining follow-up: full E2E middleware matrix. Subprocess observation timeout kill landed in fb37c82.

[rille111]

Review request (agent core)

Problem: Stale turn-end file-mutation footer after a failed patch/write_file when a later tool legitimately changes the same file.

Contract: CONTENT-TRANSITION verifier — safely observed local content change may clear the footer; fail closed when observation is unavailable. Not payload-equality validation.

Please review these commits (branch is rebased onto main, nothing else on it):

• 8064355 - verifier module + wiring + tests
• fb37c82 - failsafe hardening (subprocess observation timeout kill, registry dispatch ContextVar, footer tests)
• 64b7e60 - fail closed on unparseable mutation targets

Suggested test focus:

scripts/run_tests.sh tests/run_agent/test_file_mutation_verifier.py
scripts/run_tests.sh tests/agent/test_file_mutation_verifier_redesign.py
scripts/run_tests.sh tests/agent/test_turn_finalizer_file_mutation_footer.py
scripts/run_tests.sh tests/run_agent/test_tool_batch_segmentation.py

Touches: agent/file_mutation_verifier.py, agent/tool_executor.py, model_tools.py, run_agent.py, turn_context / turn_finalizer, tests only.

[alt-glitch]

This was generated by AI during triage.

Related: #53165 and #65584 address the same stale verifier-footer outcome with narrower/different observation mechanisms. This content-transition approach is not a duplicate, but the live PR also carries extensive unrelated inherited history; please rebase or isolate the requested verifier commits before maintainers choose a mechanism.

[rille111]

The rebase was already done, this triage ran right as I force-pushed (e992fa3 -> 913ec28). The PR is now exactly 3 verifier commits, no inherited history:

• 9b2a6dc verifier module + wiring + tests
• 913ec28 failsafe hardening
• f37f29f fail closed on unparseable mutation targets

Diff touches agent/file_mutation_verifier.py, executor/turn wiring and tests only. I updated the description, the old note about desktop commits at base was stale.

On mechanism: this one requires an observed SHA-256 content change (not stat metadata, so the chmod case flagged on #65584 keeps the footer) and fails closed when observation is unavailable. It is also built on the current segmented tool-batch executor, the drift called out on #53165. Happy to adapt to whatever contract maintainers pick.

[rille111]

Rebased onto current main (551e1c6), same 3 commits. No content changes except one legacy test updated to the fail-closed contract from the third commit (test_missing_path_arg_recorded_nowhere -> test_missing_path_arg_fails_closed). Verifier suites: 87 passed locally.

[teknium1]

Thanks for isolating the content-transition approach and preserving a fail-closed observation contract. The underlying stale-footer case is real on current main: run_agent.py:3272-3298 only reconciles write_file/patch outcomes, so a later terminal edit cannot clear the entry.

Problems

• agent/turn_finalizer.py:413-426 now emits a footer after an interrupted or empty turn. Current main deliberately suppresses that (agent/turn_finalizer.py:413-416) after it has closed and persisted an interrupted tool tail (agent/turn_finalizer.py:289-291; agent/message_sanitization.py:307-311). This can deliver a footer while the durable assistant row remains Operation interrupted.
• agent/tool_dispatch_helpers.py:60-63,157-159 serializes every write_file and patch. Current main explicitly permits independent file-tool paths concurrently (agent/tool_dispatch_helpers.py:60-61); the verifier should not regress that batch behavior without a narrower ordering strategy.

Suggested changes

• Preserve the interrupt gate or make delivered and persisted interrupted responses identical.
• Add an executor-level failed-patch → terminal-edit regression; the branch's direct Path.write_text test does not exercise the claimed dispatch path.

Automated hermes-sweeper review.

[teknium1]

This resurrects a user-visible response after an interrupt. finalize_turn already closes and persists the interrupted tool tail before this section; on an empty interrupt that row is Operation interrupted.. Please retain the interrupt gate, or update the durable close path so the delivered footer and persisted assistant content cannot diverge.

[teknium1]

This drops the existing independent-path concurrency contract for every write_file and patch, not only ambiguous middleware-rewritten calls. Please keep the path-scoped fast path where final effective paths can be safely determined, rather than making all structured mutations sequential barriers.

[rille111]

Still conflicted against current main after a rebase attempt.

Why a plain rebase is insufficient

main evolved agent/tool_executor.py to the _ManagedToolResult / middleware-authorization path. This PR’s tip still uses the older (result, args, registry_dispatched) triple return. There are 13 conflict hunks in tool_executor.py alone, plus related call-site churn in run_agent.py.

Next step (not yet pushed)

Surgical port onto latest main:

1. Keep main’s _ManagedToolResult middleware shape
2. Bring in agent/file_mutation_verifier.py + prepare/finalize hooks
3. Wire prepare_mutation_dispatch / observe-after through managed execute paths
4. Re-run verifier + batch segmentation suites

Leaving the existing branch tip unchanged so review history stays intact until that port is ready.