Cheat SheetSOP Step 21 — Reference Card
Forward-Deployed Engineer — Core Architecture & Invariant Patterns
Key mental models, system boundaries, protocol invariants, and latency/cost trade-off tables.
Architectural Invariants When designing and assessing systems in the Forward-Deployed Engineer domain, observe the following non-negotiable architectural rules:
| Dimension | Standard Production Pattern | Anti-Pattern | Failure Implication |
|---|---|---|---|
| **Interface Contracts** | Strict Schema Validation (Zod / JSON Schema) | Implicit Type Coercion | Downstream pipeline breakage and silent corruptions |
| **State Management** | Externalized, Partitioned Session Stores | In-Memory Local Global State | Session loss upon horizontal autoscaling or restarts |
| **Error Handling** | Exponential Backoff with Jitter | Tight Re-try Loops | Thundering herd collapse and upstream cascading exhaustion |
| **Resource Budgets** | Hard Timeout Bounds & Cost Ceilings | Unbounded Async Polling | Runaway cloud billing and connection exhaustion |
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