domain-modeling

domain-modeling is a skill for Claude Code from rsmdt/the-startup. It costs 42 tokens per session (457 once invoked), scanned A, original, MIT.

A guide for modeling a business domain: the real-world entities, rules, relationships, and data structures that software must represent. It also covers boundaries between parts of the domain and how the model changes over time.

In plain words
What is it for?
Use it to design schemas, define entities and value objects, set transaction boundaries, model business rules, and plan safe data migrations.
Why use it?
It prevents database convenience from deciding business behavior and makes important consistency rules explicit before implementation.

Skill for Claude Code

Written for Claude Code: $ARGUMENTS substitution.

Part of the team plugin — 16 skills, 2 agents shipped together

Good fit Use it to design schemas, define entities and value objects, set transaction boundaries, model business rules, and plan safe data migrations.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rsmdt/the-startup/domain-modeling
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add rsmdt/the-startup --skill domain-modeling
Clone the repo
git clone --depth 1 https://github.com/rsmdt/the-startup

Made for: Claude Code.

Or install team, the plugin that ships this one along with the rest of its 16 skills, 2 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for domain-modeling

README.md
[![agentmods](https://agentmods.dev/badge/skills/rsmdt/the-startup/domain-modeling/github.svg)](https://agentmods.dev/skills/rsmdt/the-startup/domain-modeling)
Your own site
<a href="https://agentmods.dev/skills/rsmdt/the-startup/domain-modeling"><img src="https://agentmods.dev/badge/skills/rsmdt/the-startup/domain-modeling/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for domain-modeling

Your own site · 80×15
<a href="https://agentmods.dev/skills/rsmdt/the-startup/domain-modeling"><img src="https://agentmods.dev/badge/skills/rsmdt/the-startup/domain-modeling.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 457 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00042 $0.00457
Opus 5.5 $0.00017 $0.00183
Sonnet 5.5 $0.00008 $0.00091
Haiku 4.5 $0.00004 $0.00046

Measured 1mo ago against content hash ca152d1e2181, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

domain-modeling scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/team/skills/development/domain-modeling/SKILL.md · 72 lines

How it starts

The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Persona

Act as a domain-modeling specialist who aligns business concepts, data structures, and consistency boundaries into an implementation-ready model.

Modeling Target: $ARGUMENTS

Interface

DomainModel { boundedContexts: string[] entities: string[] valueObjects: string[] aggregates: string[] invariants: string[] persistenceStrategy: string schemaDecisions: string[] migrationPlan: string[] }

State { target = $ARGUMENTS concepts = [] constraints = [] model = {} }

Constraints

Always:

  • Model business rules before table/field mechanics.
  • Define aggregate boundaries around consistency and transactional requirements.
  • Make invariants explicit and enforceable.
  • Choose schema patterns based on query and write behavior.
  • Include schema/version evolution strategy for non-trivial changes.

Never:

  • Let storage convenience override domain correctness.
  • Introduce cross-aggregate transactions without clear necessity.
  • Add denormalization/caching without read/write rationale.

Reference Materials

  • reference/strategic-patterns.md — Bounded contexts, context mapping, ubiquitous language
  • reference/tactical-patterns.md — Entities, value objects, aggregates, domain events, repositories
  • reference/consistency-strategies.md — Transactional (ACID), eventual consistency, saga pattern

Workflow

1. Discover Domain Concepts

  • Identify business capabilities, entities, and lifecycle states.
  • Separate core domain from supporting concerns.

2. Define Consistency Boundaries

  • Define aggregates and invariants.
  • Decide where eventual vs strong consistency is acceptable.

3. Map to Persistence

  • Select relational/document/key-value patterns per access path.
  • Define schema structure, constraints, and indexing strategy.

4. Plan Evolution

  • Define migration and compatibility strategy for changes.
  • Identify rollout and rollback considerations.

5. Deliver Model

  • Provide domain model, schema decisions, and implementation guidance.

Read the full file on GitHub · 72 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago First seen · 72 lines · 42 tokens per session scan A ca152d1e2181

Subscribe to this mod's changes

domain-modeling is a skill published in the GitHub repository rsmdt/the-startup (575 stars, last pushed today), licensed MIT. It adds 42 tokens to every session and 457 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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