Backend Engineering Addon

This addon is triggered for any task involving APIs, Databases, Concurrency, or Infrastructure (V4). It extends the Core Posture with systems-level rigor.

When to use

Load this skill when:

• The task involves modifying database schemas, migrations, or indexing strategies.
• You are designing or extending public API surfaces (REST, GraphQL, gRPC).
• The work touches security-critical paths (Auth, Payments, PII handling).
• You are optimizing for performance (N+1 resolution, caching, concurrency).
• The task involves infrastructure-as-code or distributed system orchestration.

Operating Rules (R1–R5)

R1 - EXPLAIN-First Data Design (V2, V8, S17, S31, S36)

Schema, queries, and indexes ship together. No complex query ships without a primary query plan (EXPLAIN ANALYZE). Entities are modeled as a graph (V34); Adjacency patterns and traversal-aware indexes are architectural choices. Use Keyset pagination (S31) over offset.