The preserved worktree is invisible to the only consumer that can act on it.
Completes the #88113 fix. That change correctly stops the destructive prune
when a git probe fails, but still returns commits=0 / dirty=False -- values
that were never measured. Those are the defaults the prune used to delete on,
so the failure payload is byte-identical to "inspected fine, child left
nothing":
inspection FAILED, uncommitted work kept -> {commits: 0, dirty: False, pruned: False}
inspected OK, child produced nothing -> {commits: 0, dirty: False, pruned: False}
The only failure signal was a logger.warning, and the sole consumer of this
payload is the parent agent reading the serialized delegate_task entry -- it
cannot read logs (no in-repo code reads the key back). So the parent's rational
reading of the failure case is "the child produced no work", which is the exact
wrong conclusion: a worktree possibly full of uncommitted work is preserved and
then never looked at. The data survives but nobody is told to recover it.
Changes:
- subagent_worktree: one _unproven() helper stamps inspection_failed + a note
naming the worktree/branch, warns, and returns the payload. Both unproven
exits route through it, so they cannot drift apart again.
- subagent_worktree: the pre-existing exception path (timeout, OSError, a
non-numeric rev-list stdout) produced the same unproven payload but logged at
DEBUG -- effectively silent. It now takes the same flagged path as a non-zero
exit; identical outcomes get identical reporting.
- delegate_tool: the caller's finalize-raised fallback assigned the
creation-side metadata dict (path/branch/repo_root/base_commit) -- a disjoint
schema missing commits/dirty/pruned. It now emits the same flagged shape, and
logs at WARNING.
- Docs + docstring + module contract now state that pruning requires
affirmative proof, so a future cleanup doesn't "fix" the preserved worktree
by restoring the unconditional prune and reintroducing this P1.
Purely additive: the happy-path payload shape is unchanged, so no existing
reader can break.
Validation:
- 18/18 tests/tools/test_subagent_worktree.py; 127 passed across the delegation
suites (test_delegate, batch_validation, control_actions, timeout_diagnostic).
- 3 new guards mutation-checked: neutering the flag fails all three; reverting
the production file to pre-fix main fails all three. Restores checksum-verified.
- E2E on real git: inspection-failure now returns inspection_failed=true with
work intact on disk; proven-clean still prunes (pruned=true).
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