Domainkit

---
name: domainkit
description: >-
  Maintain a project's domain model as a consented record of settled understanding: the CONTEXT.md overview and glossary of the ubiquitous language, and docs/adr/ decision records. Use when a domain term needs pinning down, when a hard-to-reverse trade-off decision gets settled, when the user says "update the glossary" or "write an ADR", or when another skill needs the domain model kept current; when the user says "set up CONTEXT.md" or "write the project overview"; or when the user asks "is CONTEXT.md still accurate" or says "audit the glossary".
license: MIT
allowed-tools: Read, Write, Edit, Grep, Glob, AskUserQuestion, Bash(git log:*)
metadata:
  internal: false
---

# domainkit

Scribe of the project's **domain model**. domainkit keeps two living artifacts current: **`CONTEXT.md`**, a short overview of what the product is and who it is for followed by a glossary of the project's ubiquitous language, and **`docs/adr/`**, the log of architectural decisions and why they were made. Its core loop is narrow on purpose, **detect the moment, offer to record it, write on consent**, so the vocabulary and the reasoning behind hard choices stay pinned down without anyone remembering to do it.

It runs primarily as a **byproduct of design work**. While a decision is being grilled, a plan drafted, or code written, a term crystallizes or a decision lands. That's when domainkit fires, proposes the entry, and writes it once you say yes. Two explicit modes sit beside that loop: one seeds `CONTEXT.md` for a project in a single pass, and one checks later whether it still matches the code.

## When this fires

Route to one of three modes:

- **`record`**, the default. A **domain term** needs pinning down, because it's vague, overloaded, or two words are being used for one concept. Or a **decision** gets settled that meets the [ADR bar](#the-adr-decision-record-format). Also on explicit asks: "record this decision", "write an ADR", "update the glossary", "add this term to the ubiquitous language", "/domainkit". And when another skill needs the domain model kept current, it defers here rather than carrying the format itself.
- **`init`.** The user asks to seed the domain model: "set up CONTEXT.md", "write the project overview", "domainkit init". It reads the repo, interviews the owner once, and proposes a whole `CONTEXT.md`.
- **`audit`.** The user asks whether the model still holds: "is CONTEXT.md still accurate", "audit the glossary", "domainkit audit". statuskit routes here when `CONTEXT.md` has fallen behind the code.

**A model-fired run always routes to `record`.** `init` and `audit` run only when the user asks for them, because each reads the whole repo and proposes a large diff, and that cost is the user's to choose.

Two things domainkit deliberately is **not**:

- **Not the interrogator.** Challenging a term, inventing edge-case scenarios, stress-testing whether a decision holds: that's an interrogation step. domainkit records the *settled* understanding; if a term or decision is still genuinely unresolved, use grillkit when installed or ask the user to settle it directly rather than writing down a guess. `init` does ask the owner questions, but only for facts the code cannot answer, each with a recommended answer.
- **Not a status tracker.** There is no `status.md` and no "current state" file. Project status is ambient: issues track what's planned, git and session history track what happened, a handoff compacts state on demand. domainkit persists only what those *can't* recover, meaning what the product is for, the vocabulary, and the reasoning behind irreversible choices.

## Consent (every mode)

Every write is **consent-gated**: domainkit writes only after an explicit yes. `record` offers each entry on its own. `init` and `audit` show the whole proposed change, the full file or the full diff, and write it once on one yes. A misfire costs one dismissible offer, never a spurious file.

## The modes

The mode bodies live in one file each under `modes/`. Route with [When this fires](#when-this-fires), read that one file, and follow it. Everything in this file applies to every mode and is not restated in the mode files.

- Mode `record` → read [modes/record.md](modes/record.md), then follow it.
- Mode `init` → read [modes/init.md](modes/init.md), then follow it.
- Mode `audit` → read [modes/audit.md](modes/audit.md), then follow it.

## The CONTEXT.md format

`CONTEXT.md` is the single source of truth for **what the product is and what its words mean**: a short overview, then a Domain-Driven-Design ubiquitous language. It is not a spec, not a status file, and not a README.

```markdown
# <Context name>

<1–2 sentence description of this context.>

## Overview

### What it is
<3 lines or fewer.>

### Who it is for
<3 lines or fewer.>

### The problem it solves
<3 lines or fewer.>

### Core capabilities
- <7 bullets or fewer, one capability each>

### Non-goals
- <3 lines or fewer: what the product deliberately does not do>

## <Optional grouping subheading>

### <Term>
<Tight definition. What it *is*, in 1–2 sentences.>
_Avoid: <synonym to reject>, <another>_
```

**The overview.** It gives the glossary its frame and fits on one screen.

- **Five parts, in this order.** What it is, Who it is for, The problem it solves, Core capabilities, Non-goals. Each part is 3 lines or fewer, and Core capabilities is 7 bullets or fewer.
- **What it is is required.** Any other part may be left out when the owner says it does not matter.
- **Purpose and audience, never usage.** The overview states why the product exists and for whom. It never repeats install or usage text from the README; link the README instead.
- **Optional for an existing file.** A `CONTEXT.md` with no overview stays valid. `init` offers to add one, and nothing flags a file only because it lacks one.

**The glossary.** Every `##` section other than `## Overview` holds terms.

- **Content allowed.** Terms specific to *this* project's domain; concepts unique to the work.
- **Content forbidden.** General programming concepts (timeouts, error types, utility patterns), however heavily used. If it isn't domain-specific, it doesn't belong here.
- **Definition style.** Define *what a term is*, not what it does; one or two sentences.
- **Be opinionated.** When multiple words exist for one concept, choose the best and push the others to `_Avoid_`.
- **No size cap.** A glossary grows with the domain; never evict a real term to hit a length target.

**The content rule: overview and glossary only.** No status, stage, roadmap, or metrics, because those go stale and live in the tracker. No decisions, because those are ADRs; a term may link the ADR that shaped it. No install or usage steps, because those are the README.

**Multiple contexts.** When bounded contexts clearly diverge, keep a `CONTEXT-MAP.md` at the repo root listing each context, where its file lives, and the relationships between them; split lazily, only once one file stops making sense. In a multi-context project the `## Overview` block lives in `CONTEXT-MAP.md`, above the context list, because it describes the whole product. Each per-context `CONTEXT.md` keeps its 1–2 sentence description and its glossary, with no overview of its own.

## The ADR decision record format

ADRs live in `docs/adr/` and use `NNNN-adr-<slug>-YYYY-MM-DD.md`, numbered sequentially with zero-padding: `0001-adr-use-postgres-2026-07-23.md`, `0002-adr-adopt-event-log-2026-07-24.md`, … The number leads so a listing reads in decision order, matching the serial every other `docs/` artifact carries. The number is the authoritative decision order and the ISO suffix is the creation date; never rename an ADR merely because its status changes later. To number a new one, scan `docs/adr/` for the highest existing decision number and increment. A repo whose ADRs still use the older `adr-NNNN-<slug>-YYYY-MM-DD.md` shape keeps its numbers; write the new ADR in the new shape, and point the user at repokit's `docs` mode (when installed) to rename the older ones. Create the directory only when the first ADR is needed. Parallel branches may claim the same number; when that happens, renumber the later ADR during merge and update any references to it, including `Status` lines that name it.

```markdown
# NNNN: <Title>

<1–3 sentences: what the context was, what was decided, and why.>

## Status
proposed | accepted | accepted, supersedes ADR-NNNN | deprecated | superseded by ADR-NNNN

## Considered Options
- <rejected alternative worth remembering, and why it lost>

## Consequences
- <non-obvious downstream effect>
```

Title, the context/decision/why paragraph, and `Status` make a complete ADR. `Status` is **required** on every new record, because supersession has to flip it. `Considered Options` and `Consequences` are **optional**; include one only when it adds value. A record that supersedes others says so in its own `Status` line: `accepted, supersedes ADR-NNNN`.

**Write an ADR only when all three hold:**

1. **Hard to reverse.** Changing course later carries real cost.
2. **Surprising without context.** A future reader will question the approach from the code alone.
3. **A genuine trade-off.** Real alternatives existed and were weighed.

Typical qualifiers: architectural structure (monorepo layout, event sourcing), integration approaches between contexts, technology choices with high switching cost (database, auth provider), boundary and scope definitions, deliberate deviations from convention, constraints invisible in code (compliance, performance), and non-obvious rejections of an alternative.

## Notes

- **Consent holds even when auto-fired.** Being model-invoked never means writing unprompted, because the offer always comes first.
- **Bias toward the high bar.** Better to fire on a genuinely conflicting term or a genuinely irreversible decision than to nag on every noun; when in doubt, stay quiet.
- **No filesystem or shell** (e.g. a browser-based agent)? Print the proposed glossary entry, ADR, or whole `CONTEXT.md` as a codeblock for the user to save, and skip the file write. With no `git log`, `audit` compares against the current tree only. Everything else is unchanged.