| Term | Definition |
|---|---|
| Agent | An autonomous AI subagent that performs a specific analysis or coordination task |
| BDD | Behaviour-Driven Development — a method of specifying software behaviour using Given/When/Then scenarios |
| Bounded context | A DDD concept — a boundary within which a domain model and its language are consistent and unambiguous |
| Claude Code | Anthropic’s command-line AI coding assistant |
| CLAUDE.md | A project-level configuration file that defines operational guardrails for Claude Code — build commands, conventions, and rules |
| Content curation | The process of converting raw screenshots and transcripts into structured, analysis-ready formats |
| Context map | A DDD concept — a diagram showing the relationships between bounded contexts |
| Curated transcript | An interview transcript with off-topic content removed, preserving domain knowledge verbatim |
| DDD | Domain-Driven Design — a software design approach that models software around business domains |
| Feature decomposition | The process of breaking a PRD down into individually deliverable feature specifications |
| Feature specification | A self-contained document describing a single deliverable feature, including user stories, wireframes, acceptance criteria, and effort estimates |
| HTML mockup | A semantic, unstyled HTML file representing the UI of a legacy application screen |
| LAP | Legacy Application Programme — Defra’s programme for modernising legacy systems |
| Mermaid | A diagramming language that renders charts and diagrams from text-based definitions |
| PII | Personally Identifiable Information — any data that could identify a specific individual |
| Plugin | An extension for an AI coding assistant that adds skills, agents, and hooks for a specific domain |
| PRD | Product Requirements Document — the comprehensive requirements document produced by the reverse engineering process |
| Ralph | A CLI tool that runs Claude Code in autonomous loops to build software feature by feature |
| Ralph loop | An autonomous build cycle where each iteration spawns a fresh Claude Code session to implement, test, and commit a single task |
| Reverse engineering | The process of analysing an existing system to understand its behaviour, structure, and requirements |
| Sandbox | An isolated devcontainer environment in which ralph runs Claude Code safely with unrestricted permissions |
| Skill | A reusable command defined in a plugin or extension that performs a specific task |
| Subdomain | A DDD concept — a distinct area of the business domain, classified as core, supporting, or generic |
| T-shaped team | A team where members have deep expertise in one area but can flex across other roles |
| Ubiquitous language | A DDD concept — the shared vocabulary used by the team and stakeholders within a bounded context |
AI-Enabled Legacy Modernisation Playbook
A step-by-step guide to using AI-assisted reverse engineering to produce Product Requirements Documents from legacy application artefacts, developed by Defra's Legacy Application Programme.
