Architecture Characteristics

Architecture Characteristics

Produce a small, justified set of qualities that shape the design, with their meanings, scope and priorities made explicit. A shortlist guides design attention; it is not a list of the only requirements the system must satisfy.

Workflow

1. Establish scope and evidence. Obtain the business operation/domain, affected users, critical failure/change situations, requirements and stakeholder concerns. Identify decision owners and known constraints. For an existing system, inspect relevant incidents, traffic, deployment/change history and dependency diagrams. For greenfield, label forecasts and assumptions; do not invent baseline measurements.
2. Elicit candidates before ranking. Read eliciting-and-capping.md when creating or revising a list or resolving stakeholder priorities. Link each candidate to an explicit requirement, a stakeholder concern or an inference from domain evidence. Confirm inferred needs with the responsible stakeholder; a plausible inference is not an approved requirement.
3. Test architectural relevance. Ask what success condition the quality expresses, why it matters here, and what structural choice or risk it could influence. Keep domain rules and constraints visible even when they are not quality labels. A concern need not require extra components to matter: rejecting an unsafe structure is a structural consequence. Separate desired outcomes from proposed mechanisms; preserve verified technology/version mandates as constraints rather than ranking them as qualities.
4. Make the names discriminating. For each proposed driver, state a short scenario: stimulus, operating/failure conditions, affected operation and expected response with a measure or explicit unresolved target. Read definitions-and-composites.md for ambiguous pairs, composites or apparent consistency/availability conflicts. Do not fabricate a threshold to make a row look complete.
5. Prioritize without deleting obligations. Separate mandatory constraints and baseline quality requirements from the drivers receiving design attention. Compare business impact and difficulty/risk of achieving the scenarios; record disagreements. A small top set is useful, but neither a fourth valid concern nor missing automation is grounds to discard it. Revisit the set when scenarios expose new needs.
6. Check scope and hand off. State whether each driver applies to a journey, domain, component or shared dependency. Multiple services do not establish independent quanta; use architecture-coupling-and-quanta if deployment/runtime coupling is unresolved. Preserve end-to-end and shared obligations across local lists. Hand off design-option comparison to architecture-trade-off-analysis.

Rules that prevent false agreement

• A stakeholder's “reliability” can remain a useful umbrella if its required outcomes are named. Decompose enough to expose distinct decisions, without counting parent and children as independent votes or imposing a universal vocabulary.
• Not top priority does not mean unnecessary. Record retained baseline obligations, deferred candidates and rejected candidates distinctly, with reasons and reconsideration triggers.
• A measurement gap is a risk to resolve, not evidence that the concern is unimportant. Name the needed evidence, owner and next check. Continue provisional elicitation while withholding unsupported approval or exact ranking.
• Suspected conflicts require the same operation, environment and success definitions. Attribute names alone do not prove a trade-off; neither scalability nor elasticity mandates a particular consistency model.
• Scale the record to uncertainty and consequences, not headcount or number of deployables. One critical service can require careful elicitation; a small change may need only one row.
• When a quality standard or taxonomy is invoked, read taxonomy-and-iso.md. A checklist can reveal omissions but cannot choose priorities or waive a requirement.

Minimum deliverable

For a small request: scope, candidate/driver, evidence, observable meaning, priority rationale and unresolved question or next validation. For a full list, also identify the top focus, other retained drivers, baseline constraints, and Others Considered with reasons and review triggers. State who confirmed the priorities; label an unconfirmed list provisional.

Use architecture-decision-making for a durable decision record, architecture-fitness-functions for implementing checks, and slo-and-alerting for operational targets. This skill supplies enough scenario detail to validate the selection, not a full test harness or architecture evaluation.

When evaluating the skill itself, use validation-cases.md. Written cases are not executed evidence.