Design

Use this skill when a feature needs architecture, integration, interface, operational, or validation decisions captured durably before breakdown, whether the input comes from discover.md, direct prompting, or current implementation review.

Read these references when relevant:

• references/system-design-template.md for the required system-design.md structure and quality bar
• references/behavioral-systems.md when the feature includes shared state, routing, connection/session reuse, concurrency, retries, recovery, or protocol error mapping
• references/config-surface-governance.md when the feature touches configuration, startup, compatibility boundaries, environment injection, or test harness inputs

Responsibilities

1. Translate project framing into a concrete technical approach.
2. Capture architecture, interfaces, data flow, and constraints.
3. Make major tradeoffs, risks, and assumptions explicit.
4. Define the validation strategy needed before implementation starts.
5. Produce feature-scoped PlantUML diagrams that clarify the system design.
6. Make failure handling, recovery behavior, and concurrency invariants explicit when they materially affect correctness.
7. Reuse existing typed configuration and state carriers before introducing new control surfaces.