Arch orchestrator

Architecture Orchestrator

Overview

Turn a raw product brief into a consistent, implementation-ready spec pack under specs/ by coordinating specialist agents and enforcing a project's preferred stack (frontend, backend, and AI).

When to Use

• User provides a software brief and wants full project architecture/spec docs
• User wants "screen-by-screen + backend + API + AI" markdown files
• User says "create architecture", "generate specs", "turn my brief into documentation"
• User wants an opinionated stack (design system + deployment platform) applied consistently across the whole spec pack

When NOT to Use

• Simple one-off questions about architecture patterns
• When user already has spec files and just needs edits
• Code implementation tasks (use after specs are approved)

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Preference System (SOURCE OF TRUTH)

1) Preference File Search Order

1. specs/preferences.yaml (recommended)
2. specs/preferences.json
3. .arch-orchestrator/preferences.yaml
4. .arch-orchestrator/preferences.json

If none exist, create specs/preferences.yaml using the default template (see templates/preferences.example.yaml), and record this in specs/decisions.md.

2) Design System Sources Search Order

1. design-system/ folder (any of: README.md, tokens.*, components.*, patterns.*, a11y.*)
2. specs/design-system-source.md
3. docs/design-system.md

If none exist, generate specs/design-system.md as a "Design system not provided" doc.

3) How Preferences Are Applied

• Treat preferences as hard constraints unless explicitly marked as optional
• Every generated spec must include:
  • The chosen packages/libraries and why they exist in the architecture
  • How they are wired into the repo
  • Any constraints they impose (build/deploy/runtime limits)
• Subagents must be instructed to read and comply with specs/preferences.yaml first, then the brief

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Output Contract (MUST)

Create (or update) these files in specs/:

File	Purpose
specs/index.md	Navigation hub with links to all specs
specs/brief-normalized.md	Structured extraction of the product brief
specs/preferences.yaml	Stack preferences (create if missing)
specs/design-system.md	Design tokens, components, a11y rules
specs/frontend-specs.md	Screen-by-screen UI specifications
specs/backend-specs.md	Domain model, services, database schema
specs/api-docs.md	Endpoint documentation with schemas
specs/ai-services.md	AI/LLM features (or "Not in scope")
specs/decisions.md	Architectural decisions and rationale
specs/open-questions.md	Uncertainties needing clarification

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Workflow

Phase 0: Load Preferences + Design System

1. Load preferences

   • Find and parse a preference file using the search order above
   • If missing, create specs/preferences.yaml using the default template
   • Normalize into a short "Stack Summary" section for all specs

2. Load design system sources

   • If design-system/ exists, summarize it into specs/design-system.md
   • If only a doc exists, consolidate it
   • If nothing exists, produce a default DS doc matching chosen UI libraries

3. Propagate constraints

   • Every Task prompt must include: "Follow specs/preferences.yaml as hard constraints."

Phase 1: Normalize the Brief

1. Locate the brief

   • Look for: brief.md, spec.md, requirements.md, product-brief.md
   • If not found, ask user where it is

2. Extract and structure

   • Project name and purpose
   • Goals and non-goals
   • User roles and personas
   • Key workflows and user journeys
   • Technical constraints (merge with preferences; preferences win)
   • Required integrations
   • Success metrics

3. Write specs/brief-normalized.md

Phase 2: Define Shared Foundations (Backend First)

Write specs/backend-specs.md first with:

1. Canonical domain model (SOURCE OF TRUTH)

   • Core entities with fields, types, constraints
   • Relationships between entities

2. Platform blueprint (from preferences)

   • Compute layer selection rationale
   • Storage selection (D1 vs KV vs R2 vs Durable Objects)
   • Deployment model and environment separation

3. Auth/authz model (from preferences)

   • Authentication approach (JWT, session, OAuth)
   • Authorization model (RBAC, ABAC)
   • Multi-tenancy strategy

4. Error conventions

   • Standard error envelope format
   • HTTP status code usage
   • Error code taxonomy

5. Observability + operations (from preferences)

   • Logging, error tracking, metrics
   • Analytics approach

6. Complete the backend spec

   • Services architecture
   • Database schema with indexes
   • Background jobs and queues
   • Security and rate limiting

Phase 3: Spawn Specialist Agents (Preference-Aware)

Use the Task tool to spawn agents in parallel:

API Documentation Agent:

Task tool with:
- subagent_type: "general-purpose"
- prompt: "Create comprehensive API documentation in specs/api-docs.md.
          HARD CONSTRAINTS: Follow specs/preferences.yaml.
          Reference the canonical domain model from specs/backend-specs.md.
          Include all endpoints with request/response schemas, auth requirements,
          error handling, and pagination conventions."

Frontend Specs Agent:

Task tool with:
- subagent_type: "general-purpose"
- prompt: "Create granular frontend specifications in specs/frontend-specs.md.
          HARD CONSTRAINTS: Follow specs/preferences.yaml and specs/design-system.md.
          Use the preferred UI component source and icon strategy.
          Reference entities from specs/backend-specs.md and endpoints from specs/api-docs.md.
          Provide screen-by-screen breakdown with component-level detail."

AI Services Agent (ONLY if AI features mentioned or ai.enabled=true):

Task tool with:
- subagent_type: "general-purpose"
- prompt: "Create AI services architecture in specs/ai-services.md.
          HARD CONSTRAINTS: Follow specs/preferences.yaml.
          Include AI feature inventory, model gateway, prompt management, RAG strategy,
          safety guardrails, evaluation framework, and cost controls."

Phase 4: Create Index and Decision Logs

1. Index (specs/index.md)

   • Navigation hub with links to all specs
   • One-paragraph summary per document
   • "Stack Summary" pulled from preferences

2. Decisions (specs/decisions.md)

   • All assumptions made
   • Rationale for key architectural choices
   • Stack choices (must match preferences)

3. Open questions (specs/open-questions.md)

   • Uncertainties needing clarification
   • Trade-offs to discuss with team

Phase 5: Consistency Validation

Before finishing, verify:

• Preferences applied across FE/BE/API/AI specs
• Entity names identical across all specs
• API routes in frontend-specs.md exist in api-docs.md
• Permissions consistent (screen access = endpoint access)
• Data schemas match between FE/BE/API
• All agent tasks completed successfully
• All open questions captured

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Assumptions + Questions

Ask at most 5 critical questions only if blockers exist:

• Must choose between fundamentally different approaches (e.g., session vs jwt)
• Must know tenancy model for multi-tenant apps
• Must clarify data residency / compliance requirements

Otherwise, proceed with explicit assumptions and document in specs/decisions.md.

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Error Handling

Condition	Action
Preferences missing	Create defaults, record in decisions.md
Design system missing	Generate default DS doc, record assumptions
Brief missing	Ask user where it is
Brief vague	Proceed with assumptions, document in decisions.md
AI features unclear	Default to ai.enabled preference; otherwise "not in scope"
Agent fails	Document issue in open-questions.md, continue with other specs