# Requirements Traceability System - Technical Specification

## System Overview

A **graph-based requirements traceability and linking system** enabling spec-driven development across multi-language projects (Python, Go, Rust, TypeScript) with support for smart contracts and ARUs.

## Core Concepts

### Requirement Types (Nodes)
1. **Epic**: High-level business objective
2. **Feature**: Deliverable capability
3. **UserStory**: User-facing requirement (As a... I want... So that...)
4. **TechnicalSpec**: Implementation specification
5. **TestCase**: Validation/verification artifact
6. **CodeArtifact**: Source code file/function
7. **UIArtifact**: Wireframe/design/mockup
8. **ServiceSpec**: API/service contract
9. **DatabaseSchema**: Data model requirement
10. **SmartContract**: Blockchain contract specification

### Link Types (Edges)
- `decomposes_to`: Parent → Child hierarchy
- `implements`: Spec → Code
- `tests`: TestCase → Requirement
- `validates`: Code → Requirement
- `references`: Cross-domain linking
- `blocks`: Dependency blocking
- `depends_on`: Prerequisite dependency
- `related_to`: Semantic relationship

### Attributes (All Nodes)
```
id: UUID
type: RequirementType
title: string
description: string
status: [draft, active, deprecated, archived]
priority: [critical, high, medium, low]
owner: string
created_at: timestamp
updated_at: timestamp
version: integer
tags: [string]
metadata: {key: value}
```

## Data Storage

### SQLite Schema
```sql
-- Core tables
requirements (id, type, title, description, status, priority, owner, created_at, updated_at, version)
links (id, source_id, target_id, link_type, metadata, created_at)
versions (id, requirement_id, version_num, valid_from, valid_to, data_snapshot)
tags (id, requirement_id, tag_name)

-- Indexes
CREATE INDEX idx_req_type ON requirements(type)
CREATE INDEX idx_req_status ON requirements(status)
CREATE INDEX idx_links_source ON links(source_id)
CREATE INDEX idx_links_target ON links(target_id)
```

### Graph Query Patterns
- Transitive closure: Find all descendants
- Impact analysis: Find all dependents
- Coverage: Find untested requirements
- Completeness: Find unimplemented specs

## CLI Architecture

### Command Structure
```
rtm init <project>              # Initialize project
rtm create <type> <title>       # Create requirement
rtm link <source> <target> <type>  # Create link
rtm list [--type] [--status]    # List requirements
rtm show <id>                   # Display requirement
rtm decompose <id>              # Show hierarchy
rtm impact <id>                 # Show dependents
rtm export [--format]           # Export RTM
rtm version <id>                # Show version history
rtm search <query>              # Full-text search
```

### TUI Features
- Interactive requirement browser
- Graph visualization (ASCII/Unicode)
- Inline editing
- Batch operations
- Real-time search

## Integration Points

### Code Extraction
- Parse `@req:REQ-123` annotations
- Extract docstring requirements
- Link to test decorators

### Test Linking
- Map test functions to requirements
- Track coverage percentage
- Validate test completeness

### Compiler/Linter Hooks
- Validate requirement completeness
- Check for orphaned requirements
- Enforce traceability rules

## Versioning & Temporal Data

### Bi-Temporal Model
- `valid_from`: When requirement became active
- `valid_to`: When requirement was superseded
- Supports "as-of" queries for historical state
- Enables requirement evolution tracking

### Branching
- Support parallel requirement versions
- Merge strategies for convergence
- Conflict resolution

## MCP Integration

### Tools Exposed
- `create_requirement`: Create new requirement
- `link_requirements`: Create traceability link
- `query_graph`: Execute graph queries
- `get_coverage`: Calculate coverage metrics
- `export_rtm`: Generate RTM matrix

## Success Metrics

1. **Traceability**: 100% of code linked to requirements
2. **Coverage**: All requirements have test cases
3. **Completeness**: No orphaned requirements
4. **Performance**: <100ms for graph queries
5. **Usability**: CLI operations <5 commands

