# β Close-out — Cycle #273

**Issue:** #273 — Rebase-collision integrity guard: prevent silent loss of upstream content at integration  
**Branch:** cycle/273  
**Verdict:** APPROVED  
**Merge commit:** 43c5ea6a  
**β session:** R1 → RC, R2 → RC, R3 → APPROVED

## Review Context

**Triadic cycle** implementing pre-push git hook to prevent silent loss of upstream content during rebase-integration cycles. Addresses confirmed failure class from γ #268 where COHERENCE-FOR-AGENTS.md and CTB vision §8.5.2 were silently dropped during rebase and required manual restoration.

**Implementation scope:** eng/ship skill text, pre-push hook script, installer, test fixture, CDD cross-references (release/gamma skills).

**Review progression:**
- **R1:** Implementation not committed (F1-F3) → RC
- **R2:** Implementation complete, CI infrastructure issue (F4) → RC  
- **R3:** CI green, all ACs met → APPROVED

## Merge Evidence

**Branch CI state:** GREEN (completed/success on commit 3bacacad)  
**Merge method:** `git merge --no-ff cycle/273` from main  
**Merge commit message:** "Merge cycle/273: rebase-collision integrity guard. Closes #273"  
**Integration verification:** All 7 ACs satisfied with committed artifacts

**Pre-merge gate compliance:**
1. ✅ Identity truth: `beta@cdd.cnos`  
2. ✅ Canonical-skill freshness: `origin/main` current at session start
3. ✅ Non-destructive merge-test: not required (textual changes only, no new contract surface)

## Cycle Findings

**No new findings.** Standard triadic progression: α implementation → β review/RC → α fix → β approve → merge. CI infrastructure issue (F4) was repository-wide (Go version in build.yml), not cycle-specific, resolved by δ's syntax fix.

**Process observations:**
- False review-readiness signal pattern (R1 F2): α signaled ready with uncommitted implementation. Self-corrected in fix-round.
- CI gate effectiveness: Rule 3.10 correctly blocked approval until infrastructure resolved, maintaining integration quality.

**Implementation quality:** Comprehensive hook script addresses exact failure class from evidence, proper bypass mechanisms, thorough test coverage, minimal CDD cross-references as specified.

## Integration Record

**Files integrated:**
- `src/packages/cnos.eng/hooks/pre-push` — executable hook script
- `src/packages/cnos.eng/scripts/install-hooks.sh` — installer  
- `src/packages/cnos.eng/skills/eng/ship/SKILL.md` — rebase-integrity section
- `src/packages/cnos.eng/hooks/test-pre-push-rebase-integrity.sh` — test fixture
- `src/packages/cnos.cdd/skills/cdd/release/SKILL.md` — cross-reference
- `src/packages/cnos.cdd/skills/cdd/gamma/SKILL.md` — cross-reference  
- `.cdd/unreleased/273/self-coherence.md` — α artifact
- `.cdd/unreleased/273/beta-review.md` — β artifact

**Next phase:** δ owns tag/deploy/release boundary. γ owns post-release assessment.