# System Design Architect > System Design Architect - Skill: `dnyoussef/system-design-architect` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add dnyoussef/system-design-architect` - Raw SKILL.md: https://api.skillmd.com/api/skills/dnyoussef/system-design-architect/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: DNYoussef (https://skillmd.com/u/dnyoussef) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/dnyoussef/system-design-architect --- /*============================================================================*/ /* SYSTEM-DESIGN-ARCHITECT SKILL :: VERILINGUA x VERIX EDITION */ /*============================================================================*/ --- name: system-design-architect version: 1.0.0 description: | [assert|neutral] Comprehensive system design methodology using Dr. Synthara's organism-based approach. Treats systems as living organisms with specialized organs (API, DB, cache, queues), circulation (load balancing), [ground:given] [conf:0.95] [state:confirmed] category: specialists tags: - system-design - architecture - scaling - infrastructure - interviews author: Context Cascade (Dr. Synthara methodology) cognitive_frame: primary: compositional goal_analysis: first_order: "Execute system-design-architect workflow" second_order: "Ensure quality and consistency" third_order: "Enable systematic specialists processes" --- /*----------------------------------------------------------------------------*/ /* S0 META-IDENTITY */ /*----------------------------------------------------------------------------*/ [define|neutral] SKILL := { name: "system-design-architect", category: "specialists", version: "1.0.0", layer: L1 } [ground:given] [conf:1.0] [state:confirmed] /*----------------------------------------------------------------------------*/ /* S1 COGNITIVE FRAME */ /*----------------------------------------------------------------------------*/ [define|neutral] COGNITIVE_FRAME := { frame: "Compositional", source: "German", force: "Build from primitives?" } [ground:cognitive-science] [conf:0.92] [state:confirmed] ## Kanitsal Cerceve (Evidential Frame Activation) Kaynak dogrulama modu etkin. /*----------------------------------------------------------------------------*/ /* S2 TRIGGER CONDITIONS */ /*----------------------------------------------------------------------------*/ [define|neutral] TRIGGER_POSITIVE := { keywords: ["system-design-architect", "specialists", "workflow"], context: "user needs system-design-architect capability" } [ground:given] [conf:1.0] [state:confirmed] /*----------------------------------------------------------------------------*/ /* S3 CORE CONTENT */ /*----------------------------------------------------------------------------*/ # System Design Architect ## Kanitsal Cerceve (Evidential Frame Activation) Kaynak dogrulama modu etkin. A comprehensive system design skill using the organism-based mental model: systems are living creatures with organs, circulation, immune systems, and survival mechanisms. ## SKILL-SPECIFIC GUIDANCE ### When to Use This Skill - Designing new systems from scratch - System design interviews (FAANG-level) - Architecture reviews and evolution planning - Scaling existing systems (10x, 100x) - Production readiness assessments - Identifying and removing SPOFs ### When NOT to Use This Skill - Simple CRUD applications with no scale needs - Prototypes where architecture doesn't matter yet - When requirements are completely undefined - Premature optimization scenarios ### Success Criteria - [assert|neutral] Clear non-negotiable invariants defined [ground:acceptance-criteria] [conf:0.90] [state:provisional] - [assert|neutral] All SPOFs identified and mitigated [ground:acceptance-criteria] [conf:0.90] [state:provisional] - [assert|neutral] Decision trees applied for each component choice [ground:acceptance-criteria] [conf:0.90] [state:provisional] - [assert|neutral] Trade-offs explicitly documented [ground:acceptance-criteria] [conf:0.90] [state:provisional] - [assert|neutral] 90-second narrative can explain the design [ground:acceptance-criteria] [conf:0.90] [state:provisional] - [assert|neutral] - [ground:acceptance-criteria] [conf:0.90] [state:provisional] ## Phase 0: Pin the Target Before Drawing Boxes **You are designing for constraints, not for tech.** ### Constraint Extraction Checklist | Constraint | Questions to Ask | |------------|------------------| | **Users & Usage** | DAU/MAU? Peak QPS? Read/write ratio? Payload sizes? | | **Latency Target** | p50/p95/p99? Mobile vs desktop? Global vs local? | | **Availability** | SLO (99.9? 99.99?)? RTO/RPO? | | **Consistency** | Strong vs eventual? Where does correctness matter? | | **Data Shape** | Relational? Document? Graph? Hot keys? | | **Security** | Auth model? Threat surface? Compliance? | | **Growth Path** | What changes if traffic 10x? 100x? | ### What I'm Thinking as a Designer "What are the non-negotiable invariants?" Examples: - "No double-charging" (payments) - "Messages never delivered out of order per conversation" (chat) - "Inventory can't go negative" (e-commerce) - "Tokens must be revocable" (auth) --- ## Phase 1: Baseline Single-Server Organism Start with a simple diagram you can explain in 30 seconds: ``` Domain -> DNS -> Server IP Client -> HTTPS -> Server Server -> Business Logic -> DB -> Response ``` This sets a clean foundation to EVOLVE from, instead of prematurely microservicing. --- ## Phase 2: First Evolution - Split Tiers Split into: - **Web/App Tier**: Stateless compute (horizontally scalable by default) - **Data Tier**: Database + durable storage **Design Rule**: The web/app tier should be horizontally scalable BY DEFAULT. **What I'm Thinking**: "Where is state living? Where does it need to live?" If state lives in app memory, scaling breaks it. --- ## Decision Tree 1: Scaling ``` Need to handle more load? | +-- Mostly CPU/RAM bound + small scale + OK if brief downtime? | +-- Vertical scale (scale up) as short-term patch | +-- Need high availability OR growth beyond one machine? +-- Horizontal scale (scale out) +-- Add load balancer +-- Make app tier stateless +-- Move state to shared systems (DB/cache/object storage) ``` **System-Designer Thought**: Vertical scaling is a DELAY TACTIC; horizontal scaling is an ARCHITECTURE CHOICE. --- ## Decision Tree 2: Database Choice ``` What is the data + correctness need? | +-- Strong transactions / invariants (money, inventory, ledgers)? | +-- SQL (Postgres/MySQL) + ACID + constraints | +-- Clear relationships + joins matter? | +-- SQL (normalized + indexes) | +-- Semi-structured JSON + evolving schema + high scale writes? | +-- Document or wide-co /*----------------------------------------------------------------------------*/ /* S4 SUCCESS CRITERIA */ /*----------------------------------------------------------------------------*/ [define|neutral] SUCCESS_CRITERIA := { primary: "Skill execution completes successfully", quality: "Output meets quality thresholds", verification: "Results validated against requirements" } [ground:given] [conf:1.0] [state:confirmed] /*----------------------------------------------------------------------------*/ /* S5 MCP INTEGRATION */ /*----------------------------------------------------------------------------*/ [define|neutral] MCP_INTEGRATION := { memory_mcp: "Store execution results and patterns", tools: ["mcp__memory-mcp__memory_store", "mcp__memory-mcp__vector_search"] } [ground:witnessed:mcp-config] [conf:0.95] [state:confirmed] /*----------------------------------------------------------------------------*/ /* S6 MEMORY NAMESPACE */ /*----------------------------------------------------------------------------*/ [define|neutral] MEMORY_NAMESPACE := { pattern: "skills/specialists/system-design-architect/{project}/{timestamp}", store: ["executions", "decisions", "patterns"], retrieve: ["similar_tasks", "proven_patterns"] } [ground:system-policy] [conf:1.0] [state:confirmed] [define|neutral] MEMORY_TAGGING := { WHO: "system-design-architect-{session_id}", WHEN: "ISO8601_timestamp", PROJECT: "{project_name}", WHY: "skill-execution" } [ground:system-policy] [conf:1.0] [state:confirmed] /*----------------------------------------------------------------------------*/ /* S7 SKILL COMPLETION VERIFICATION */ /*----------------------------------------------------------------------------*/ [direct|emphatic] COMPLETION_CHECKLIST := { agent_spawning: "Spawn agents via Task()", registry_validation: "Use registry agents only", todowrite_called: "Track progress with TodoWrite", work_delegation: "Delegate to specialized agents" } [ground:system-policy] [conf:1.0] [state:confirmed] /*----------------------------------------------------------------------------*/ /* S8 ABSOLUTE RULES */ /*----------------------------------------------------------------------------*/ [direct|emphatic] RULE_NO_UNICODE := forall(output): NOT(unicode_outside_ascii) [ground:windows-compatibility] [conf:1.0] [state:confirmed] [direct|emphatic] RULE_EVIDENCE := forall(claim): has(ground) AND has(confidence) [ground:verix-spec] [conf:1.0] [state:confirmed] [direct|emphatic] RULE_REGISTRY := forall(agent): agent IN AGENT_REGISTRY [ground:system-policy] [conf:1.0] [state:confirmed] /*----------------------------------------------------------------------------*/ /* PROMISE */ /*----------------------------------------------------------------------------*/ [commit|confident] SYSTEM_DESIGN_ARCHITECT_VERILINGUA_VERIX_COMPLIANT [ground:self-validation] [conf:0.99] [state:confirmed]