Validation Driven Design

Validation-Driven Design

Purpose and boundary

Design an architecture under explicit requirements and specifications, then strengthen it through evidence-bearing iterations. This skill is for architecture creation, redesign, or architecture audit, not routine codebase refactoring, interface styling, generic review, or UI prototyping.

Produce an evidence-bounded architecture direction. Include drivers, constraints, load-bearing mechanisms, semantic boundaries, claims, and validation gates. Do not expand into detailed module decomposition unless a claim under test requires it.

Treat applicable context, glossary, requirements, and other domain artifacts as current inputs. Preserve their sources and established meanings. When they are absent or contradictory, record an explicit assumption or open question and coordinate with the user. Do not infer domain knowledge from technical theory, external systems, or a prototype.

Preserve the stated product vision as a falsifiable requirement. If evidence contradicts it, reopen the architecture or requirement explicitly; never make the work “pass” by silently narrowing the promise.

Use this skill to establish that the architecture meets its requirements, important design decisions have enough support, and the necessary checks are clear. Establish these before judging whether the architecture's complexity is proportionate to the current goal.

Scale validation work to the importance of the design decision and a concrete risk or open question. If more validation is not justified, simplify or postpone that part of the design instead of weakening its checks. Follow the selected mode's limits in REFERENCE.md.

REFERENCE.md §1 defines an executable conformance case and its minimum fields.

Quick start

1. Choose lightweight, full-design, or audit-only mode; name the artifact owners and human decision owner.
2. Write goals, non-goals, invariants, quality attributes, and production constraints. Keep artifact and decision lifecycle status separate from claim evidence state.
3. Map load-bearing mechanisms to mature theory and external systems; fan out independent research when justified, then verify, synthesize, and record adoption and proof gaps.
4. Rank architecture uncertainties and run only the smallest discriminating validation.
5. Feed dogfooding back into requirements, decisions, terms, specifications, executable conformance cases, and gates.
6. Audit the four design axes and cross-cutting quality attributes; keep non-claims explicit.

See REFERENCE.md for templates and proof obligations, and EXAMPLES.md.

Workflow

The sections below define the full-design route. In lightweight mode, execute only the mode minimum and add a step when its falsifier or risk requires it; do not generate full matrices or portfolios by default. In audit-only mode, pin the baseline, evaluate the claimed scope, report gaps, and stop without redesign or edits unless the user requests them.

For full-design, use the design contract from section 1 as shared input to iterative research fan-out followed by primary-agent synthesis. Based on the research complexity, delegate the research to an appropriate number of subagents. Each subagent independently explores relevant theories, external systems, primary sources, counterevidence, and open questions. If subagents are unavailable, run separate sequential research passes and disclose the missing independence.

Treat subagent reports as research leads, not as evidence or authority. After each research wave, the primary agent must inspect the load-bearing primary sources, compare their provenance, reconcile agreements and conflicts, and identify evidence gaps. It must synthesize and report the results accurately, including unresolved conflicts and limitations, then recommend one or two architecture directions or next research steps with their evidence and trade-offs. At the human decision gate, the designated human decision owner decides whether to stop, update the architecture direction, or run another exploratory or targeted research wave. Keep unresolved gaps open.

In lightweight mode, use research fan-out only when the selected falsifier requires independent research. In audit-only mode, use it only to verify evidence within the pinned scope. Do not let research fan-out expand either mode or replace the independent adversarial review required by REFERENCE.md §5.

1. Establish the design contract

• Read repository guidance and current authoritative artifacts before proposing structure.
• Turn outcomes into traceable requirements, scope, non-goals, invariants, failures, and quality attributes.
• Build one authority map, which can include a one-way reference graph. Give every normative fact one owner; derived artifacts reference it.
• Preserve each supplied claim's source and identifier. Keep artifact or decision lifecycle status separate from claim evidence state. Reuse the repository's claim evidence field when its meaning matches the distinctions below; do not add a second field for claim evidence state. Record an explicit mapping when the names differ.
• If no claim evidence field exists, start a claim evidence ledger: proposed, theory-supported, confirmed-narrowly, conformance-proven, production-proven, open, and non-claim.
• For iterative work or handoff, give each new driver, claim, and decision a stable identifier that follows repository conventions. Report added, changed, and retired identifiers.

2. Ground the abstractions

• Select mature theory for the actual design question, not for prestige or vocabulary.
• State the mechanism, invariant, representation boundary, proof boundary, and a disconfirming case.
• When semantics and execution differ, separate authoring form, typed/validated meaning, canonical public semantics, and implementation-private execution.

3. Research external systems

• Prefer pinned primary specifications and mature implementations.
• When research is fanned out, each subagent independently identifies relevant external systems and primary sources. Require pinned primary sources and explicit counterevidence or exclusions.
• Record each influence's problem, adoption, owner, exclusions, dependency, evidence, and upgrade.
• External systems are provenance unless the local contract explicitly makes one normative. Never create peer authorities or unsupported “compatible with” claims.

4. Design seams and alternatives

• Compare at least the selected design, a credible alternative, and the simplest non-adoption path.
• Design only enough structure to discriminate the load-bearing claim. Treat detailed responsibility and module placement as separate structural decisions unless they are under test.
• Define ownership, lifecycle, identity, extension, failure, and observability boundaries.
• Ask whether two independent implementations could both satisfy the prose yet produce different observable behavior. If yes, the contract is incomplete.
• Distinguish configuration/content additions, extension modules, framework semantics, and truly irreducible core changes.

5. Validate the highest-risk uncertainty

• Charter one question, falsifier, smallest slice, discriminating cases, time box, and deletion plan.
• Choose the evidence form from the uncertainty: prototype, permanent executable conformance case, or independent review. Architecture semantics usually need executable or independently interpreted artifacts.
• Treat prototype/review results as design evidence, never conformance, production authority, or human acceptance.

6. Synthesize dogfooding and iterate

• Classify design effect as confirmed-no-change, refined-adopted, gap-opened, or no-design-effect; then update claim evidence state separately.
• Attribute defects to the narrowest honest layer: instance/configuration → template/profile → extension module/package → framework/schema → irreducible kernel.
• Update each owning artifact once; remove duplicated normative restatements. Preserve research at a fixed reference and promote only durable scenarios, executable conformance cases, or decisions into authority.
• For each adopted refinement or open gap, report the effect on architecture drivers, constraints, and structural decisions. This lets later work revisit only the affected scope.
• Stop disposable prototyping when the risk class is resolved. Move remaining proof into permanent conformance assets and end-to-end production slices.

7. Run design-axis and quality-attribute gates

Treat specialized criteria supplied by a candidate architecture as structural evaluation criteria, not acceptance criteria. Bind each criterion to an authoritative requirement, specification, decision record, or explicitly scoped architecture contract before using it. Requirements retain ownership of acceptance criteria. Use the generic axes below to assess evidence coverage and unresolved interactions, not to replace the bound criteria.

• Abstraction: theory-grounded boundaries hide implementation choices without hiding semantics.
• Completeness: every known requirement, refusal, interaction, and operational concern maps to a mechanism plus an observable verification path.
• Orthogonality: use an orthogonal basis as a system metaphor for the load-bearing concerns. Completeness checks whether these concerns cover the current claim scope. Orthogonality checks whether each concern is necessary and non-overlapping. Each concern must have a distinct meaning and reason to change, and it must vary independently. Test their composition for hidden shared state, cross-product effects, and unspecified precedence.
• Extensibility: declared variation enters through extension contracts; an out-of-family witness must not require core or host-dispatch changes.
• Use REFERENCE.md's detailed delivery gates, including migration, security, observability, recovery, rollout, and rollback proportional to the real installed base.

Output

Select the output contract by mode:

• For full-design, include all applicable items below.
• For lightweight, return the mode minimum and only the items produced by the selected bounded check. Do not add alternatives, structural-placement decisions, or adopted refinements unless the check required them.
• For audit-only, return the pinned baseline and scope, authorities, observed architecture direction and claims, evidence gaps, design-axis findings, findings about cross-cutting quality attributes, completion gaps, and recorded human decision outcome. Do not propose alternatives, structural placements, refinements, or edits unless the user requests redesign or edits.

The full-design output includes:

1. Authority sources, assumptions, and open input conflicts.
2. Goals, non-goals, architecture drivers, invariants, and quality attributes.
3. The selected architecture direction and the alternatives considered.
4. Load-bearing mechanisms, semantic boundaries, claims, claim evidence states, evidence, and non-claims.
5. Decisions that require concrete structural placement, with stable identifiers for iterative work or handoff.
6. Validation results, adopted refinements, open gaps, and affected authoritative artifacts.
7. Remaining gates and the required human decision.

Completion

Do not declare the architecture complete from prose quality, a green build, framework analogies, or passing disposable prototypes. Complete the audit in REFERENCE.md: trace every requirement and decision, verify each quality axis with appropriately scoped evidence, reconcile live artifacts, preserve explicit non-claims, and leave production gates executable. Apply the full completion checklist only in full-design mode. For other modes, satisfy the selected mode's minimum and record excluded checks as out of scope or non-claims, not as missing deliverables. The designated human decision owner must accept, reject, or condition the architecture and explicitly authorize or withhold the next gate; evidence and agents cannot self-approve.