Root Cause

The validator tracked output and collect as variable-producing keys in bash steps — but never added output_exit_code, which was introduced alongside bash step branching in Dec 2025.

Any recipe using output_exit_code for exit-code branching would receive a false-positive "variable not defined" error on validation.

Fix

3-line addition to validator.py to include output_exit_code alongside the existing variable producers.

2 regression tests with full TDD red-green cycle — test written first (red), fix applied (green), confirmed no regressions in the 397-test suite.

Impact

• Recipes using exit-code branching validate correctly
• 397 existing tests: all passing ✓
• 2 new regression tests added

LLM as Synthesis Gate, Not Primary Validator

Phase 6 forks: bash quick-pass for clean repos (fast, zero LLM cost), LLM synthesis only when Phases 2–4 surface issues. Clean repos never pay the LLM tax.

Graceful Degradation by Design

Phase 0 detects available tooling before any work begins. Missing optional dependencies trigger clean fallbacks — not failures. Runs in minimal environments without modification.

Deterministic Classification

Phase 5 quality tiers — critical / needs_work / polish / good — are computed algorithmically from structured findings, not LLM opinion. Reproducible, auditable, CI-friendly.

Opt-In Flags

Both flags default to "false" — existing validate-bundle-repo runs are unaffected until teams opt in.

Updated Components

• Quality classification — incorporates recipe validation findings alongside agent validation results
• Synthesize-report — unified output covering both agents and recipes in one report
• Phase ordering — recipe validation slotted at 2.7, before final synthesis

Zero Breaking Changes

v3.3.0 is fully backward-compatible. Teams using validate-bundle-repo today see no change to behavior or output until they explicitly set validate_recipes or validate_all to "true".