Fixture. This page is the stdout of
wayfinder skill domain-modeling, run against a config with tracker value github cli and two registered ticket skills (grill-design, pre-mortem). Change either and this render changes with it.Supporting files. The
## Disclosed files block below names 2 ids an agent can fetch on its own. Each is served here too: domain-modeling/adr-format, domain-modeling/context-format.$ wayfinder skill domain-modeling74 lines
1# Domain Modeling
2
3Actively 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.)
4
5## File structure
6
7Most repos have a single context:
8
9```
10/
11├── CONTEXT.md
12├── docs/
13│ └── adr/
14│ ├── 0001-event-sourced-orders.md
15│ └── 0002-postgres-for-write-model.md
16└── src/
17```
18
19If a `CONTEXT-MAP.md` exists at the root, the repo has multiple contexts. The map points to where each one lives:
20
21```
22/
23├── CONTEXT-MAP.md
24├── docs/
25│ └── adr/ ← system-wide decisions
26├── src/
27│ ├── ordering/
28│ │ ├── CONTEXT.md
29│ │ └── docs/adr/ ← context-specific decisions
30│ └── billing/
31│ ├── CONTEXT.md
32│ └── docs/adr/
33```
34
35Create 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.
36
37## During the session
38
39### Challenge against the glossary
40
41When 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?"
42
43### Sharpen fuzzy language
44
45When 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."
46
47### Discuss concrete scenarios
48
49When 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.
50
51### Cross-reference with code
52
53When 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?"
54
55### Update CONTEXT.md inline
56
57When 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).
58
59`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.
60
61### Offer ADRs sparingly
62
63Only offer to create an ADR when all three are true:
64
651. **Hard to reverse** — the cost of changing your mind later is meaningful
662. **Surprising without context** — a future reader will wonder "why did they do it this way?"
673. **The result of a real trade-off** — there were genuine alternatives and you picked one for specific reasons
68
69If any of the three is missing, skip the ADR. Use the format in [ADR-FORMAT.md](./ADR-FORMAT.md).
70
71## Disclosed files
72
73- `wayfinder skill domain-modeling/adr-format` — when you are recording an architectural decision
74- `wayfinder skill domain-modeling/context-format` — when you are writing or updating the glossary