# Principal Systems Engineer Review — Round 3

**Branch:** `colonyos/the_following_github_issue_is_the_source_feature_description_treat_it_as_the_pri`
**PRD:** `cOS_prds/20260329_225200_prd_the_following_github_issue_is_the_source_feature_description_treat_it_as_the_pri.md`

## Test Results

- **443 tests pass** (zero failures, zero regressions)

## Checklist

| Category | Item | Status |
|----------|------|--------|
| **FR-1** | `_friendly_error()` detects overloaded/529/503 patterns | PASS |
| **FR-2** | `_is_transient_error()` structured attrs first, regex fallback | PASS |
| **FR-3** | `run_phase()` retry loop with restart-from-scratch | PASS |
| **FR-4** | Default config (3 attempts, 10s base, 120s max, full jitter) | PASS |
| **FR-5** | `RetryConfig` dataclass nested in `ColonyConfig` | PASS |
| **FR-6** | Optional `fallback_model` with own retry pass | PASS |
| **FR-7** | Hard-blocked fallback on review/decision/fix | PASS |
| **FR-8** | Retry status logged via UI or `_log()` | PASS |
| **FR-9** | `RetryInfo` on `PhaseResult`, serialized to RunLog | PASS |
| **FR-10** | Parallel phases retry independently | PASS |
| **Quality** | No TODO/placeholder code | PASS |
| **Quality** | Follows established conventions | PASS |
| **Quality** | No unnecessary dependencies | PASS |
| **Safety** | No secrets/credentials | PASS |
| **Safety** | Safety-critical phases hard-blocked from fallback | PASS |
| **Safety** | Error handling for all failure paths | PASS |

## Previous Round Findings — Resolution Status

| # | Finding | Status |
|---|---------|--------|
| 1 | `resume` kwarg leaks into retry attempts | FIXED — `current_resume` set to `None` after first transient failure |
| 2 | `_is_transient_error(exc)` called 3x on same exception | FIXED — extracted to `is_transient` local boolean |
| 3 | `_SAFETY_CRITICAL_PHASES` uses raw strings | FIXED — now uses `Phase.REVIEW.value`, etc. |
| 4 | `_friendly_error()` uses bare `"529" in lower` substring match | FIXED — now uses `_TRANSIENT_PATTERNS` regex |
| 5 | `for/else/continue/continue` pattern | FIXED — simplified control flow |
| 6 | No test for `resume` + retry interaction | FIXED — `test_resume_cleared_after_transient_error` added |

---

VERDICT: approve

FINDINGS:
- [src/colonyos/orchestrator.py:2441]: `RetryInfo(**p["retry_info"])` deserializes run log JSON via blind `**kwargs` splat — if `RetryInfo` gains or loses a field, old/stale logs will raise `TypeError`. Should use explicit field extraction for forward/backward compat. LOW severity — only affects loading historical logs after schema evolution.
- [src/colonyos/agent.py:220-230]: Total attempts can reach `2 * max_attempts` when fallback is configured. A user setting `max_attempts=10` with `fallback_model=sonnet` gets 20 total attempts. The `max_attempts > 10` warning partially mitigates this but no hard cap exists. LOW severity — documented in docstring.
- [src/colonyos/config.py:639]: `base_delay_seconds=0` is accepted (non-negative), enabling zero-delay tight retry loops. Full jitter of `uniform(0, 0) = 0` means instant retries bounded only by `max_attempts`. LOW severity — power-user footgun.
- [src/colonyos/agent.py:258-260]: When permanent error hits on last attempt, `transient_errors += 1 if is_transient else 0` is correct but the conditional increment is less readable than `if is_transient: transient_errors += 1`. Cosmetic.
- [src/colonyos/orchestrator.py]: `retry_config=config.retry` threaded through 20+ call sites — acknowledged tech debt, not a blocker per previous rounds.

SYNTHESIS:
This is a clean, well-placed transport-level retry layer. It sits at exactly the right architectural level — inside `run_phase()`, invisible to the orchestrator's heavyweight recovery system — so transient 529 errors resolve transparently without triggering diagnostic agents or nuke recovery. The key design decisions are all correct: structured status_code detection before regex fallback with word-boundary patterns, full jitter for decorrelation across parallel phases, `resume` session ID cleared after first transient failure (session is dead), frozen `RetryInfo` dataclass for immutable metadata, and hard safety gates preventing model fallback on review/decision/fix phases. The `_run_phase_attempt()` refactor cleanly separates the single-query concern from retry orchestration. Config validation is thorough — positive max_attempts, non-negative delays, allowlisted fallback models, warning on high attempt counts. All 10 functional requirements are implemented, all previous review findings are resolved, and 443 tests pass with zero regressions. The remaining findings are all LOW severity polish items. This implementation treats error classification and retry metadata with the rigor appropriate for a system that runs autonomously with real budget on the line. Approved.
