Produce a structured architectural plan with explicit goals, trade-offs, and visual diagrams. Use when designing new systems, refactoring architecture, or evaluating technical decisions. User intent drives scope and focus—adapt structure to what they ask for; ask questions when intent is unclear.

Gather context: Check readme, docs, codebase as reference—inform the plan but stay open to proposing changes that diverge from current state
Define goals: State clear objectives aligned with user intent; distinguish must-haves vs nice-to-haves
List considerations: Constraints, trade-offs, risks, alternatives—scope to what matters for the user’s question
Create diagrams: Use Mermaid (flowchart, sequence, C4, ER, etc.) to show structure, flows, boundaries—choose types and split diagrams based on intent
Summarize assumptions: Key bullets; flag deferrals for ambiguous or high-risk decisions
Output: Write to a markdown file—use path if user provided one, otherwise ask where to save; include goals, considerations, diagrams, assumptions; ## References only when rules/skills were used; offer to refine or expand

plan-architecture