Software Architecture

Use this skill to make system-level design decisions and leave an inspectable path from drivers to evidence. It owns the architecture decision workflow, not the implementation of any subsystem.

Workflow

1. Frame the decision. Establish the desired outcome, stakeholders, constraints, decision horizon, reversibility, affected systems, and evidence gaps. Do not invent scale, regulatory, latency, or ownership facts.
2. Turn qualities into scenarios. Name the architecture characteristics that matter, express each as an observable scenario, prioritize them, and expose conflicts. Load references/architecture-characteristics-and-tradeoffs.md.
3. Choose boundaries and shape. Compare styles, topology, and deployment granularity against the scenarios and team operating capacity. Load references/styles-topologies-and-granularity.md.
4. Test ownership and coupling. Identify policy, data, change, runtime, and team boundaries. Treat a service split as a hypothesis, not a default. Load references/coupling-modularity-and-data-ownership.md.
5. Make runtime behavior explicit. For asynchronous or distributed flows, specify authority, consistency, ordering, retries, duplicates, timeouts, partial failure, recovery, and reconciliation. Load references/distributed-workflows-and-consistency.md.
6. Record and verify. Capture the decision and rejected alternatives in templates/architecture-design-brief.md and templates/tradeoff-record.md; use templates/architecture-review.md for challenge and sign-off. Define fitness evidence and drift response with references/evolution-fitness-functions-and-drift.md.
7. Plan change without hiding execution ownership. Identify evolutionary slices, coexistence assumptions, and handoff conditions. Load references/migration-and-coexistence.md; route an approved transition to migration-engineering.
8. Facilitate proportionately. Match review depth to blast radius, irreversibility, uncertainty, and cross-team impact. Load references/architecture-practice-and-facilitation.md.

Output Contract

Produce an architecture decision brief or review that includes drivers, stakeholders, constraints, prioritized scenarios, candidate options, explicit tradeoffs, boundaries and ownership, runtime and failure behavior, operational implications, decisions, evidence gaps, fitness checks, evolution slices, and named owners. State what is decided, what remains open, and which specialist owns follow-up work.