Agent Architecture Review, Validation snapshot

Ensure that background work remains perceptible

The submitted code is an autonomous agentic workflow: `run()` iterates over `PULL_REQUESTS`, builds an `ExecutionPlan`, calls model review via `review_pr(...)`, gates actions through `approval_gate(...)`, and may mutate external PR state via paths such as `post_comment`, `apply_fix`, and `merge_pr`. For background perceptibility, it persists user-relevant run and PR state through `TriageState.run_status`, `state.event_log`, per-PR `rec.events`, and `save_checkpoint(...)` using a temp file plus `os.replace(...)`. It also records transitions such as `WORKFLOW_STARTED`, `PLAN_PUBLISHED`, `WORKFLOW_PAUSED`, `WORKFLOW_TERMINATED_PAUSED`, `WORKFLOW_TERMINATED_ABORTED`, and `WORKFLOW_FAILED`. `_pro…

Expose meaningful operational state, not internal complexity

The code exposes meaningful operational state through explicit enums and events rather than relying on incidental control flow. `RunStatus` distinguishes `RUNNING`, `AWAITING_APPROVAL`, `ABORTED`, `FAILED`, and `COMPLETED`; `run()` sets a single terminal value based on `terminal` and logs mutually exclusive terminal events. Per-PR statuses such as `REVIEWING`, `BLOCKED_INVALID_OUTPUT`, `BLOCKED_HIGH_RISK`, `AWAITING_APPROVAL`, `ABORTED`, `FAILED`, `SKIPPED`, and `REJECTED` are used to communicate user-relevant states. The paused terminal message tells the operator the run is awaiting approval and how to resume with `PR_AGENT_APPROVAL_<PR_ID>`.

Establish trust through inspectability

The audit serialization in `_serialize_state(...)` provides strong inspectability: it records `run_id`, `run_status`, timestamp, `hash_algorithm`, `review_model`, `plan`, PR metadata, `diff_hash`, exact `model`, exact `prompt`, `actions_taken`, `rollback_token`, structured review fields, `raw_response`, `parse_ok`, per-record events, and run-level `event_log`. Terminal events are logged before `save_audit(state, run_id)`, and `state.run_status` is set before persistence, so completed, paused, aborted, and failed outcomes are represented in the persisted audit trail.

Make hand-offs, approvals, and blockers explicit

Approval hand-offs and blockers are explicit. `approval_gate(...)` logs `APPROVAL_REQUESTED`; when no approval variable is present it sets `record.status = PRStatus.AWAITING_APPROVAL`, sets `state.run_status = RunStatus.AWAITING_APPROVAL`, logs `WORKFLOW_PAUSED` with the checked variables, checkpoints, and raises `WorkflowPaused`. `run()` converts this into `WORKFLOW_TERMINATED_PAUSED` with a specific operator instruction to supply `PR_AGENT_APPROVAL_<PR_ID>` and relaunch. Other blocker paths are distinct: invalid model output becomes `BLOCKED_INVALID_OUTPUT` and is rejected with `APPROVAL_REJECTED`; high-risk PRs become `BLOCKED_HIGH_RISK`; operator abort logs `APPROVAL_ABORT`, marks `PR_AB…