EXP-07 — Consistency on Feature Additions
EXP-02 proved the guide eliminates variance on greenfield tasks. Does that hold on feature additions? When extending an existing conforming service, both conditions produced zero variance — [0,0,0] violations across 3 runs each. The fixture itself is the dominant variable.
What the agent produced
Section titled “What the agent produced”Violations across 3 runs
Without guide With guide───────────────────── ──────────────────────────────Run 1: 0 violations ✓ Run 1: 0 violations ✓Run 2: 0 violations ✓ Run 2: 0 violations ✓Run 3: 0 violations ✓ Run 3: 0 violations ✓Variance: 0.00 Variance: 0.00Metrics
Section titled “Metrics”| Without guide | With guide | |
|---|---|---|
| Violations | [0, 0, 0] | [0, 0, 0] |
| Variance | 0.00 | 0.00 |
| Pass rate | 3/3 | 3/3 |
Finding
Section titled “Finding”Null result. On a conforming codebase, both conditions produce zero violations with zero variance.
The agent learns the architecture from the fixture itself — hexagonal structure, layer boundaries, naming conventions. The guide is redundant when the existing code already teaches the correct patterns. This confirms what EXP-04 found in a single run, now validated across 3 runs.
Contrast with EXP-02 (greenfield): without existing code to reference, the guide is the only architectural signal. That’s where it matters. On feature additions to a clean codebase, the codebase does the teaching.
What this means: The guide’s highest value is on greenfield services and codebases with inconsistent patterns. For clean, conforming services, the architecture speaks for itself.
- Task: Add a discount system to an existing conforming hexagonal orders service
- Agent: claude-sonnet-4-6
- Fixture: orders-service (hexagonal, conforming) — Mode B, embedded
- Runs: 3 per condition