backend-development-feature-development – Coding skill for AI agents

Orchestrate end-to-end feature development from requirements to production deployment:

[Extended thinking: This workflow orchestrates specialized agents through comprehensive feature development phases - from discovery and planning through implementation, testing, and deployment. Each phase builds on previous outputs, ensuring coherent feature delivery. The workflow supports multiple development methodologies (traditional, TDD/BDD, DDD), feature complexity levels, and modern deployment strategies including feature flags, gradual rollouts, and observability-first development. Agents receive detailed context from previous phases to maintain consistency and quality throughout the development lifecycle.]

Use this skill when

• Coordinating end-to-end feature delivery across backend, frontend, and data
• Managing requirements, architecture, implementation, testing, and rollout
• Planning multi-service changes with deployment and monitoring needs
• Aligning teams on scope, risks, and success metrics

Do not use this skill when

• The task is a small, isolated backend change or bug fix
• You only need a single specialist task, not a full workflow
• There is no deployment or cross-team coordination involved

Instructions

1. Confirm feature scope, success metrics, and constraints.

2. Select a methodology and define phase outputs.

3. Orchestrate implementation, testing, and security validation.

4. Prepare rollout, monitoring, and documentation plans.

Safety

• Avoid production changes without approvals and rollback plans.
• Validate data migrations and feature flags in staging first.

Tool names, role identifiers and flags below describe a workflow, not an installed executable interface. Check available tools or perform the responsibility directly. Effort estimates, coverage thresholds and rollback times are planning examples, not guarantees. A deployment switch does not reverse database writes or external side effects: prefer compatible expand/contract migrations, record a tested recovery plan and coordinate data restoration separately.

Configuration Options

Development Methodology

• traditional: Sequential development with testing after implementation
• tdd: Test-Driven Development with red-green-refactor cycles
• bdd: Behavior-Driven Development with scenario-based testing
• ddd: Domain-Driven Design with bounded contexts and aggregates

Feature Complexity

• simple: Single service, minimal integration (1-2 days)
• medium: Multiple services, moderate integration (3-5 days)
• complex: Cross-domain, extensive integration (1-2 weeks)
• epic: Major architectural changes, multiple teams (2+ weeks)

Deployment Strategy

• direct: Immediate rollout to all users
• canary: Gradual rollout starting with 5% of traffic
• feature-flag: Controlled activation via feature toggles
• blue-green: Zero-downtime deployment with instant rollback
• a-b-test: Split traffic for experimentation and metrics

Phase 1: Discovery & Requirements Planning

1. Business Analysis & Requirements

• Use Task tool with subagent_type="business-analytics::business-analyst"
• Prompt: "Analyze feature requirements for: $ARGUMENTS. Define user stories, acceptance criteria, success metrics, and business value. Identify stakeholders, dependencies, and risks. Create feature specification document with clear scope boundaries."
• Expected output: Requirements document with user stories, success metrics, risk assessment
• Context: Initial feature request and business context

2. Technical Architecture Design

• Use Task tool with subagent_type="comprehensive-review::architect-review"
• Prompt: "Design technical architecture for feature: $ARGUMENTS. Using requirements: [include business analysis from step 1]. Define service boundaries, API contracts, data models, integration points, and technology stack. Consider scalability, performance, and security requirements."
• Expected output: Technical design document with architecture diagrams, API specifications, data models
• Context: Business requirements, existing system architecture

3. Feasibility & Risk Assessment

• Use Task tool with subagent_type="security-scanning::security-auditor"
• Prompt: "Assess security implications and risks for feature: $ARGUMENTS. Review architecture: [include technical design from step 2]. Identify security requirements, compliance needs, data privacy concerns, and potential vulnerabilities."
• Expected output: Security assessment with risk matrix, compliance checklist, mitigation strategies
• Context: Technical design, regulatory requirements

Phase 2: Implementation & Development

4. Backend Services Implementation

• Use Task tool with subagent_type="backend-architect"
• Prompt: "Implement backend services for: $ARGUMENTS. Follow technical design: [include architecture from step 2]. Build RESTful/GraphQL APIs, implement business logic, integrate with data layer, add resilience patterns (circuit breakers, retries), implement caching strategies. Include feature flags for gradual rollout."
• Expected output: Backend services with APIs, business logic, database integration, feature flags
• Context: Technical design, API contracts, data models

5. Frontend Implementation

• Use Task tool with subagent_type="frontend-mobile-development::frontend-developer"
• Prompt: "Build frontend components for: $ARGUMENTS. Integrate with backend APIs: [include API endpoints from step 4]. Implement responsive UI, state management, error handling, loading states, and analytics tracking. Add feature flag integration for A/B testing capabilities."
• Expected output: Frontend components with API integration, state management, analytics
• Context: Backend APIs, UI/UX designs, user stories

6. Data Pipeline & Integration

• Use Task tool with subagent_type="data-engineering::data-engineer"
• Prompt: "Build data pipelines for: $ARGUMENTS. Design ETL/ELT processes, implement data validation, create analytics events, set up data quality monitoring. Integrate with product analytics platforms for feature usage tracking."
• Expected output: Data pipelines, analytics events, data quality checks
• Context: Data requirements, analytics needs, existing data infrastructure

Phase 3: Testing & Quality Assurance

7. Automated Test Suite

• Use Task tool with subagent_type="unit-testing::test-automator"
• Prompt: "Create comprehensive test suite for: $ARGUMENTS. Write unit tests for backend: [from step 4] and frontend: [from step 5]. Add integration tests for API endpoints, E2E tests for critical user journeys, performance tests for scalability validation. Ensure minimum 80% code coverage."
• Expected output: Test suites with unit, integration, E2E, and performance tests
• Context: Implementation code, acceptance criteria, test requirements

8. Security Validation

• Use Task tool with subagent_type="security-scanning::security-auditor"
• Prompt: "Perform security testing for: $ARGUMENTS. Review implementation: [include backend and frontend from steps 4-5]. Run OWASP checks, penetration testing, dependency scanning, and compliance validation. Verify data encryption, authentication, and authorization."
• Expected output: Security test results, vulnerability report, remediation actions
• Context: Implementation code, security requirements

9. Performance Optimization

• Use Task tool with subagent_type="application-performance::performance-engineer"
• Prompt: "Optimize performance for: $ARGUMENTS. Analyze backend services: [from step 4] and frontend: [from step 5]. Profile code, optimize queries, implement caching, reduce bundle sizes, improve load times. Set up performance budgets and monitoring."
• Expected output: Performance improvements, optimization report, performance metrics
• Context: Implementation code, performance requirements

Phase 4: Deployment & Monitoring

10. Deployment Strategy & Pipeline

• Use Task tool with subagent_type="deployment-strategies::deployment-engineer"
• Prompt: "Prepare deployment for: $ARGUMENTS. Create CI/CD pipeline with automated tests: [from step 7]. Configure feature flags for gradual rollout, implement blue-green deployment, set up rollback procedures. Create deployment runbook and rollback plan."
• Expected output: CI/CD pipeline, deployment configuration, rollback procedures
• Context: Test suites, infrastructure requirements, deployment strategy

11. Observability & Monitoring

• Use Task tool with subagent_type="observability-monitoring::observability-engineer"
• Prompt: "Set up observability for: $ARGUMENTS. Implement distributed tracing, custom metrics, error tracking, and alerting. Create dashboards for feature usage, performance metrics, error rates, and business KPIs. Set up SLOs/SLIs with automated alerts."
• Expected output: Mon

… (full content is in the download package)