106 lines
4.4 KiB
Markdown
106 lines
4.4 KiB
Markdown
---
|
|
name: domain-modeling
|
|
description: Build and sharpen a project's domain model. Use when the user wants to pin down domain terminology or a ubiquitous language, record an architectural decision, or when another skill needs to maintain the domain model.
|
|
category: "architecture"
|
|
risk: "safe"
|
|
source: "community"
|
|
source_repo: "mattpocock/skills"
|
|
source_type: "community"
|
|
date_added: "2026-06-19"
|
|
author: "Matt Pocock"
|
|
license: "MIT"
|
|
license_source: "https://github.com/mattpocock/skills/blob/main/LICENSE"
|
|
tags:
|
|
- architecture
|
|
- workflow
|
|
- coding-agents
|
|
tools:
|
|
- claude-code
|
|
- codex-cli
|
|
- cursor
|
|
---
|
|
|
|
# Domain Modeling
|
|
|
|
## When to Use
|
|
|
|
Use when this workflow matches the user request: Build and sharpen a project's domain model. Use when the user wants to pin down domain terminology or a ubiquitous language, record an architectural decision, or when another skill needs to maintain the domain model.
|
|
|
|
|
|
_Source: [mattpocock/skills](https://github.com/mattpocock/skills) (MIT)._
|
|
|
|
Actively build and sharpen the project's domain model as you design. This is the *active* discipline — challenging terms, inventing edge-case scenarios, and writing the glossary and decisions down the moment they crystallise. (Merely *reading* `CONTEXT.md` for vocabulary is not this skill — that's a one-line habit any skill can do. This skill is for when you're changing the model, not just consuming it.)
|
|
|
|
## File structure
|
|
|
|
Most repos have a single context:
|
|
|
|
```
|
|
/
|
|
├── CONTEXT.md
|
|
├── docs/
|
|
│ └── adr/
|
|
│ ├── 0001-event-sourced-orders.md
|
|
│ └── 0002-postgres-for-write-model.md
|
|
└── src/
|
|
```
|
|
|
|
If a `CONTEXT-MAP.md` exists at the root, the repo has multiple contexts. The map points to where each one lives:
|
|
|
|
```
|
|
/
|
|
├── CONTEXT-MAP.md
|
|
├── docs/
|
|
│ └── adr/ ← system-wide decisions
|
|
├── src/
|
|
│ ├── ordering/
|
|
│ │ ├── CONTEXT.md
|
|
│ │ └── docs/adr/ ← context-specific decisions
|
|
│ └── billing/
|
|
│ ├── CONTEXT.md
|
|
│ └── docs/adr/
|
|
```
|
|
|
|
Create files lazily — only when you have something to write. If no `CONTEXT.md` exists, create one when the first term is resolved. If no `docs/adr/` exists, create it when the first ADR is needed.
|
|
|
|
## During the session
|
|
|
|
### Challenge against the glossary
|
|
|
|
When the user uses a term that conflicts with the existing language in `CONTEXT.md`, call it out immediately. "Your glossary defines 'cancellation' as X, but you seem to mean Y — which is it?"
|
|
|
|
### Sharpen fuzzy language
|
|
|
|
When the user uses vague or overloaded terms, propose a precise canonical term. "You're saying 'account' — do you mean the Customer or the User? Those are different things."
|
|
|
|
### Discuss concrete scenarios
|
|
|
|
When domain relationships are being discussed, stress-test them with specific scenarios. Invent scenarios that probe edge cases and force the user to be precise about the boundaries between concepts.
|
|
|
|
### Cross-reference with code
|
|
|
|
When the user states how something works, check whether the code agrees. If you find a contradiction, surface it: "Your code cancels entire Orders, but you just said partial cancellation is possible — which is right?"
|
|
|
|
### Update CONTEXT.md inline
|
|
|
|
When a term is resolved, update `CONTEXT.md` right there. Don't batch these up — capture them as they happen. Use the format in [CONTEXT-FORMAT.md](./CONTEXT-FORMAT.md).
|
|
|
|
`CONTEXT.md` should be totally devoid of implementation details. Do not treat `CONTEXT.md` as a spec, a scratch pad, or a repository for implementation decisions. It is a glossary and nothing else.
|
|
|
|
### Offer ADRs sparingly
|
|
|
|
Only offer to create an ADR when all three are true:
|
|
|
|
1. **Hard to reverse** — the cost of changing your mind later is meaningful
|
|
2. **Surprising without context** — a future reader will wonder "why did they do it this way?"
|
|
3. **The result of a real trade-off** — there were genuine alternatives and you picked one for specific reasons
|
|
|
|
If any of the three is missing, skip the ADR. Use the format in [ADR-FORMAT.md](./ADR-FORMAT.md).
|
|
|
|
|
|
## Limitations
|
|
|
|
- Requires the upstream tool, account, API key, or local setup when the workflow names one.
|
|
- Does not authorize destructive, production, paid, or external-message actions without explicit user approval.
|
|
- Validate generated artifacts or recommendations against the user's real sources before treating them as final.
|