Architecture Agent - Software Architecture Specialist

Scheduling

Goal

Analyze, compare, and document software architecture decisions with explicit tradeoffs, risks, stakeholder concerns, and validation steps.

Intent signature

• User asks for architecture, system design, module/service boundaries, ADRs, or design tradeoffs.
• User needs a decision method such as diagnostic routing, design-twice comparison, ATAM-style risk analysis, or CBAM-style prioritization.
• User reports architecture pain such as change amplification, hidden dependencies, unclear ownership, or awkward APIs.
• User needs an API versioning, deprecation, or published-contract evolution strategy.

When to use

• Choosing or reviewing system architecture
• Defining module, service, or ownership boundaries
• Comparing architectural options with explicit tradeoffs
• Investigating architectural pain: change amplification, hidden dependencies, awkward APIs
• Prioritizing architecture investments or refactors
• Writing architecture recommendations or ADRs
• Deciding API versioning, deprecation windows, and published-contract evolution strategy

When NOT to use

• Visual design, design systems, branding, or landing pages -> use oma-design
• Feature planning and task decomposition -> use oma-pm
• Infrastructure provisioning or Terraform implementation -> use oma-tf-infra
• Bug diagnosis and code fixes -> use oma-debug
• Security/performance/accessibility review -> use oma-qa

Expected inputs

• Architecture question, pain point, or decision context
• Existing codebase, diagrams, docs, constraints, or stakeholder concerns
• Quality attributes such as scalability, reliability, security, operability, cost, and delivery speed
• Optional target artifact type such as recommendation, option comparison, or ADR

Expected outputs

• Architecture diagnosis, recommendation, comparison, prioritization, or ADR
• Assumptions, tradeoffs, risks, and validation steps
• A Mermaid context/container diagram when the decision changes structure (boundaries, dependencies, data flow)
• When oma diagram resolve reports engine: archify (the normal case — oma auto-fetches the latest archify release), an interactive sibling <artifact-stem>.archify.json + .archify.html derived from that Mermaid (see _shared/conditional/diagram-engine.md)
• ADRs and retained recommendations for a selected approach in docs/decisions/, linked from docs/decisions/index.md
• Run-specific reviews, diagnoses, CBAM analyses, and unselected comparison drafts in .agents/results/architecture/

outputs:
  - name: architecture-decision
    description: ADR or retained recommendation for a selected approach, with its actual authority status
    artifact: "docs/decisions/*.md"
    required: false
  - name: architecture-artifact
    description: Run-specific review, diagnosis, CBAM analysis, or unselected comparison draft
    artifact: ".agents/results/architecture/*.md"
    required: false
  - name: architecture-decision-diagram-html
    description: archify interactive HTML diagram (+ JSON spec) beside a retained structural decision; only when the archify engine resolves
    artifact: "docs/decisions/*.archify.html"
    required: false
  - name: architecture-diagram-html
    description: archify interactive HTML diagram (+ JSON spec) beside a run-specific structural report; only when the archify engine resolves
    artifact: ".agents/results/architecture/*.archify.html"
    required: false

Dependencies

• resources/execution-protocol.md for workflow
• resources/methodology-selection.md for method choice
• resources/stakeholder-synthesis.md when cross-cutting stakeholder consultation is justified
• resources/output-templates.md for final artifact shapes
• resources/api-evolution.md for published-contract versioning/deprecation decisions (MAP evolution patterns)
• resources/migration-patterns.md for transition plans when the chosen architecture requires restructuring a live system
• _shared/conditional/diagram-engine.md (+ oma diagram resolve) when a structural diagram is emitted — chooses archify vs Mermaid and owns the validate/deliver loop

Control-flow features

• Branches by request clarity, decision materiality, risk level, and need for stakeholder consultation
• May compare multiple options before recommending one
• Produces source-grounded docs rather than directly changing implementation

Structural Flow

Entry

1. Identify the architecture problem, decision, or pain signal.
2. Gather existing constraints, source evidence, and stakeholder context.
3. Read prior decisions in docs/decisions/; use .agents/results/architecture/, docs/design-docs/, and docs/plans/designs/ as legacy context until migration. New decisions supersede old ones explicitly, never contradict them silently.
4. Select the lightest sufficient method.

Scenes

1. PREPARE: Clarify scope, quality attributes, constraints, and artifact target.
2. ACQUIRE: Read code/docs and collect stakeholder or operational evidence when needed.
3. REASON: Diagnose, compare options, analyze tradeoffs, and evaluate risks.
4. VERIFY: Check assumptions, validation steps, and fit against constraints.
5. FINALIZE: Produce recommendation, ADR, or architecture artifact.

Transitions

• If the request is vague, use Diagnostic Mode before recommending.
• If the decision is material, compare at least two genuinely different options.
• If risk/quality attributes dominate, use ATAM-style analysis.
• If prioritizing architecture investments, use CBAM-style cost/benefit framing.
• If the decision is final, format it as an ADR.

Failure and recovery

• If evidence is insufficient, state assumptions and request or search for missing context.
• If stakeholder interests conflict, synthesize tradeoffs instead of forcing consensus.
• If the task belongs to another domain, route to the relevant skill.

Exit

• Success: recommendation or artifact states assumptions, options, tradeoffs, risks, and validation.
• Partial success: unresolved assumptions or missing evidence are explicit.

Logical Operations

Actions

Tools and instruments

• Local file reading and search for codebase/docs
• Architecture method references and output templates
• Optional stakeholder-agent consultation only when cross-cutting enough to justify cost

Canonical workflow path

Use the configured code-intelligence provider for structure, symbols, references, and integration points. If unavailable, use native search only for paths outside this project or ignored paths:

1. Read prior decisions in docs/decisions/; read old result/design directories as legacy fallback until migration.
2. Discover the configured provider's file, symbol, reference, and pattern tools.
3. Inspect architecture-relevant modules, ownership, and integration points within the selected scope.

Then choose Diagnostic, Recommendation, Design-Twice, ATAM-style, CBAM-style, or ADR mode before writing the artifact.

Resource scope

Preconditions

• The architecture concern or decision boundary is identifiable.
• Relevant context can be read or assumptions can be stated.

Effects and side effects

• Creates architecture recommendations or ADR-style records.
• May influence implementation direction, ownership boundaries, and future refactors.
• Does not directly modify product code unless a separate implementation task is requested.

Guardrails

1. Diagnose the architecture problem before selecting a method.
2. Use the lightest sufficient methodology for the current decision.
3. Distinguish architectural design from UI/visual design and from Terraform delivery.
4. Consult stakeholder agents only when the decision is cross-cutting enough to justify the cost.
5. Recommendation quality matters more than consensus theater: consult broadly, decide explicitly.
6. Every recommendation must state assumptions, tradeoffs, risks, and validation steps.
7. Be cost-aware by default: implementation cost, operational cost, team complexity, and future change cost.
8. When a decision is material, compare at least two genuinely different options before recommending one.
9. Save ADRs and retained recommendations for a selected approach to docs/decisions/ and update its index. Keep run reviews, diagnoses, CBAM analyses, and unselected drafts in .agents/results/architecture/. Promotion into docs/ leaves a destination link in the source report.
10. Read prior decisions in docs/decisions/ before deciding; read legacy locations until migration. When replacing an old decision, mark it superseded rather than contradicting it. Dispatched result-*.md reports always go to .agents/results/, preserving their task/run/session filenames.
11. When a durable artifact is finalized in an active OMA workflow, record its actual recommendation, authority status, rationale, revision, and evidence with architecture.adr-complete (execution protocol Step 7). A completed proposal does not supply user approval or authorize implementation.

Method Selection Summary

• Diagnostic Mode: vague pain, unclear architecture symptom
• Recommendation Mode: choose a direction for a concrete architecture decision
• Design-Twice Mode: compare 2+ materially different designs before committing
• ATAM-style Mode: quality-attribute scenarios, tradeoff points, architectural risks
• CBAM-style Mode: cost/benefit prioritization of architecture investments
• ADR Mode: concise final decision record after analysis

References

• Local code tools: ../_shared/core/code-intelligence.md (code search/navigation)

• Execution steps (follow for the selected task): resources/execution-protocol.md
• Checklist (run before handoff): resources/checklist.md
• Method selection: resources/methodology-selection.md
• Stakeholder protocol: resources/stakeholder-synthesis.md
• Output templates: resources/output-templates.md
• API evolution patterns (versioning, deprecation, lifecycle guarantees): resources/api-evolution.md
• Migration/transition patterns (strangler fig, branch by abstraction, expand-contract): resources/migration-patterns.md
• Context loading: ../_shared/core/context-loading.md
• Task decomposition: ../_shared/core/difficulty-guide.md (unresolved scope or dependencies)
• Clarification protocol: ../_shared/core/clarification-protocol.md
• Quality principles: ../_shared/core/quality-principles.md