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name: technical-spec description: This skill provides technical design rules including environment variable management, architecture design, and build/testing commands. Automatically loaded when discussing architecture, environment variables, build commands, or when "tech stack", "architecture pattern", "environment config", or "build command" are mentioned.

Technical Design Rules

Basic Technology Stack Policy

TypeScript-based application implementation. Architecture patterns should be selected according to project requirements and scale.

Environment Variable Management and Security

Environment Variable Management

• Centrally manage environment variables and build mechanisms to ensure type safety
• Avoid direct references to process.env, obtain through configuration management layer
• Properly implement default value settings and mandatory checks

Security

• Do not include .env files in Git
• Always manage API keys and secrets as environment variables
• Prohibit logging of sensitive information
• Do not include sensitive information in error messages

Architecture Design

Architecture Design Principles

Select appropriate architecture for each project and define clearly:

• Separation of Responsibilities: Clearly define responsibilities for each layer and module, and maintain boundaries

Unified Data Flow Principles

Basic Principles

1. Single Data Source: Store the same information in only one place
2. Structured Data Priority: Use parsed objects rather than JSON strings
3. Clear Responsibility Separation: Clearly define responsibilities for each layer

Data Flow Best Practices

• Validation at Input: Validate data at input layer and pass internally in type-safe form
• Centralized Transformation: Consolidate data transformation logic in dedicated utilities
• Structured Logging: Output structured logs at each stage of data flow

Build and Testing

Use the appropriate run command based on the packageManager field in package.json.

Build Commands

• build - TypeScript build
• type-check - Type check (no emit)

Testing Commands

• test - Run tests
• test:coverage - Run tests with coverage
• test:coverage:fresh - Run tests with coverage (fresh cache)
• test:safe - Safe test execution (with auto cleanup)
• cleanup:processes - Cleanup Vitest processes

Quality Check Requirements

Quality checks are mandatory upon implementation completion:

Phase 1-3: Code Quality Checks

• check - Biome (lint + format)
• check:unused - Detect unused exports
• check:deps - Detect circular dependencies
• build - TypeScript build

Phase 4: Tests

• test - Test execution

Phase 5: Code Quality Re-verification

• check:code - Re-verify code quality (clean up side effects from test fixes in Phase 4)

Auxiliary Commands

• check:all - Overall integrated check (check:code + test) *for manual batch verification
• open coverage/index.html - Check coverage report
• format - Format fixes
• lint:fix - Lint fixes

Troubleshooting

• Port in use error: Run the cleanup:processes script
• Cache issues: Run the test:coverage:fresh script
• Dependency errors: Clean reinstall dependencies

Coverage Requirements

• MANDATORY: Unit test coverage MUST be 70% or higher
• Metrics: Statements, Branches, Functions, Lines