New analytical lens: failure propagation chains. Opus matched GPT-5's count (10 findings each) while using 2.2x fewer tokens. Overview docs are ideal for this lens. Sonnet produced zero unique insights.
5.2 KiB
Finding #42: Failure Propagation Chain Analysis on system-overview.md
Date: 2026-05-07
Analytical lens: Failure propagation chain analysis (NEW)
Document: gargoyle's system-overview.md (323 lines) — high-level architecture overview
Models: GPT-5, Claude Opus 4.6, Claude Sonnet 4.6
Summary
New analytical lens: identify failure propagation chains — sequences where a failure in one component silently corrupts, degrades, or destabilizes another component's behavior WITHOUT triggering explicit error handling or alarms.
Results
| Model | Time | Output tokens | Reasoning tokens | Findings |
|---|---|---|---|---|
| GPT-5 | 88s | 9,027 | 6,720 | 10 |
| Claude Opus 4.6 | 97s | 4,044 | (internal) | 10 |
| Claude Sonnet 4.6 | 35s | 1,605 | (internal) | 8 |
Key Findings
Common Ground (all 3 identified)
- Shared tick event bus (EVT) as cross-user failure propagation, violating claimed user isolation (Invariant 12)
- BrokerAdapter fill misattribution/cross-user contamination through the shared port
- Stale/incorrect instrument_id resolution propagating silently through the pipeline
- Exact arithmetic boundary violation at float-to-decimal conversion at ingestion
- Recovery ordering hazards where reconciliation completes but derived state is inconsistent
GPT-5 Unique Findings
- Duplicate fills after reconnect: BrokerAdapter replays fills on reconnect with no idempotency key → duplicate lots, inflated positions. Reconciliation only helps at startup, not steady-state reconnection.
- Dual feed ingestion: Live + replay adapters simultaneously connected (port substitutability permits this) → duplicate ticks → double decisions → double exposure. No "single active feed" mutual exclusion.
- Missing live fills during steady state: Dropped fills undetected until next restart. No continuous reconciliation specified. Positions silently drift.
- PortfolioMonitor close-only outliving its trigger: No documented lifecycle for clearing → OrderManager blocks new orders indefinitely after trigger resolves.
- Instrument identity drift between market data and broker: Corporate action causes disagreement between ingestion and adapter → fills recorded against wrong instrument lineage.
Claude Opus Unique Findings
- PortfolioMonitor/Ledger divergence: PM runs as background process with own fill feed, NO reconciliation against authoritative Ledger lot state. PM's position view can drift → spurious close-only or missed close-only. Most architecturally significant: identifies PM has a PARALLEL position model with no convergence mechanism.
- Signal rejection asymmetry: SignalRisk rejections invisible to Aggregator (only approvals flow downstream). Aggregator forms decisions on systematically biased subset. Identifies this as design-level information asymmetry.
- Kill switch + fill precedence invariant deadlock: Kill switch engages while order partially filled → remaining fills forced by Invariant 6 → position grows during kill switch → PortfolioMonitor's close-only blocked by Invariant 8 → UNMANAGEABLE POSITION during crisis. Genuine deadlock between two stated invariants.
- Corporate action lot adjustment bypasses risk pipeline: Split doubles quantity → exceeds limits → no re-evaluation because risk pipeline only validates decisions, not external state changes.
Claude Sonnet Findings
- 8 findings, all also identified by GPT-5 or Opus with more depth. Zero unique insights.
- One finding (audit log corruption) based on architectural misunderstanding.
Analysis
Opus's Token Efficiency
Opus produced 10 findings in 4,044 tokens — roughly 2.2x more token-efficient than GPT-5 (10 findings in 9,027 tokens). This is the first experiment where Opus MATCHED GPT-5's finding count while using significantly fewer tokens. Previous experiments showed Opus finding fewer issues with higher insight density. Here: equal count AND higher density.
Document Level Matters
Overview/architecture documents are IDEAL for failure propagation analysis because they show boundaries and shared resources that component-level docs hide. Suggested document-level → lens matching:
- Overview docs → failure propagation, blast radius, isolation verification
- Component specs → race conditions, invariant violations, hidden assumptions
- Cross-cutting docs → temporal ordering, recovery hazards
Dominant Failure Vector
The shared infrastructure contradiction (EVT/BA as single shared nodes with claimed per-user isolation) is the single most important finding. All models caught it, each exploring different consequences:
- GPT-5: backpressure propagation, duplicate feed ingestion
- Opus: fill misattribution, PortfolioMonitor parallel state
- Sonnet: tick corruption (most obvious variant)
Practical Implications
- Run Opus for highest insight density and design tension identification (10 findings, 97s, 4K tokens)
- Run GPT-5 for operational/runtime hazards the architecture doesn't consider (10 findings, 88s, 9K tokens)
- Sonnet is redundant for this task — provides no unique value over the other two
- Total unique findings after deduplication: ~14 distinct propagation chains from a 323-line document