Adds a flag-gated escalation loop to the implementer dispatcher
(`IMPLEMENTER_ESCALATION_ENABLED=1`, default OFF). When the worker
fails in a way the predicate determines escalation can help, the
dispatcher holds the claim, resets the worktree to the prefetched
head_sha, refreshes the TTL via _claim_runtime.claim_pr, applies
the next-tier label, and re-runs the worker at the next tier — all
within the same cycle. Bounded by per-failure-class budgets in
_implementer_escalation.BUDGET_PER_FAILURE_CLASS.
Tier 2 (tier-kimi) is default-ON with a kill-switch flag
(IMPLEMENTER_ESCALATION_TIER2_ENABLED=0). Cross-cycle resumption:
the dispatcher reads auto/last-attempt-tier-N at cycle start and
seeds start_tier = min(N+1, max_tier) so crash recovery skips
known-failed tiers. Worker holds release across the cycle via the
new release_claim_on_exit: false directive — eliminates the
inter-tier claim-absent race window.
Behaviour preservation: flag=0 path is byte-equivalent to the
pre-feature build (worker prompt unchanged, Phase 4 row schema
unchanged, status-comment fingerprint unchanged). Issue work
(new_issue work group) always takes the legacy path even with
the flag on.
Supersedes the cross-cycle-only Phase 5c scheme in
auto-agents-tier-2-3-plan.md (now updated to point at the
new plan doc and the dual-role label semantics).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
drew
d3d66f3726