RLCR: Implicit two-phase structure needs explicit transition and batch review in polishing phase

[zevorn]

Context

A 12-round RLCR session completed successfully (all 8 ACs verified). The session naturally split into two distinct phases: Rounds 0-3 (plan execution, completing all original ACs) and Rounds 4-11 (quality polishing, reviewer-driven edge case hardening). While the session ultimately succeeded, the 8-round polishing phase exhibited cascading single-issue fixes and could have been compressed with batch review techniques.

Observations

1. Clear two-phase structure without explicit transition: Rounds 0-3 were "plan execution" — resolving deliverables defined in the original plan. Rounds 4-11 were "quality polishing" (marked as Review Phase) — the reviewer deep-reviewed completed code and surfaced edge cases. These two phases have fundamentally different characteristics, but RLCR treated them identically.

2. Cascading edge case chain in polishing phase: Rounds 4-11 exhibited a typical cascade pattern: fixing configuration trigger A exposed edge case B, fixing B introduced regression C, fixing C revealed interaction D. Specifically, configuration triggers were progressively expanded from one config format to another across rounds (R5→R6→R7→R9), and a behavioral stub oscillated between implementations (R8 added logic → R10 reverted → R11 restructured correct solution). The configuration matrix interaction complexity was underestimated at plan time.

3. Reviewer execution-driven discovery was highly valuable: The reviewer ran build scripts, executed configuration override tests, and verified boundary conditions — not just code reading. Most findings came from "running" rather than "reading," which is methodologically significant: pure static review would miss configuration interaction issues.

4. Implementer verification scope systematically too narrow: In nearly every round, the implementer claimed "all passing" using insufficient verification breadth. Typical pattern: testing only positive paths while missing negative paths, using search patterns that were too narrow, using universal quantifiers ("all," "nowhere") unsupported by the evidence chain.

5. Unjustified deferrals effectively corrected: In Round 0, the implementer deferred multiple tasks citing "missing environment." The reviewer disproved this by actually running the tools and demonstrating the environment was available. This highlights the reviewer's role as "fact checker."

6. Single-round output diminished sharply: The first 4 rounds each resolved multiple ACs and multiple findings. The last 8 rounds typically fixed 1-2 edge cases per round. The round-to-progress ratio in the polishing phase was significantly lower than the execution phase.

7. AC omission from immutable section repeated: One AC was not captured in the goal tracker's immutable section during initialization, and could only be tracked via Open Issues referencing the original plan. This is the same tracker initialization weakness observed in other sessions.

Suggested Improvements

#	Suggestion	Mechanism
1	Explicit phase transition marker	When all plan-scoped ACs are first marked as completed, insert an explicit phase transition. The polishing phase can adopt a different iteration strategy (e.g., batch discover + batch fix rather than one-at-a-time round-tripping).
2	Batch review findings in polishing phase	Instead of surfacing one edge case per round, the reviewer should collect all findings in a single comprehensive review pass. The implementer then addresses all of them in one round. This could compress 8 polishing rounds into 2-3.
3	Configuration interaction pre-analysis for matrix tasks	When a task involves multi-dimensional configuration options (formats × platforms × modes), require an explicit interaction analysis in Round 0 identifying which combinations trigger special paths. Avoid "discover during implementation" cascades.
4	Standardized verification checklists by task type	For different task categories (structural changes, configuration matrices, script authoring), provide standardized verification checklists. Require the implementer to check off each item before claiming completion, mitigating the "verification scope too narrow" bias.
5	Round 0 tracker completeness gate	Reviewer must verify all ACs are correctly recorded in the goal tracker's immutable section as the first step of Round 0 review, before evaluating implementation.

Quantitative Summary

Metric	Value
Total rounds	12
Exit reason	Normal completion (COMPLETE)
AC count	8 (+ 1 omitted from tracker)
Completion rate	100%
Plan execution phase (Rounds 0-3)	4 rounds — high efficiency
Quality polishing phase (Rounds 4-11)	8 rounds — low per-round output
Reviewer false positive rate	0%
Estimated compression with batching	12 → 6-8 rounds