domain-modeling

domain-modeling is a skill for Claude Code, Codex from int2t05/engineering-skills. It costs 28 tokens per session (311 once invoked), scanned A, original, MIT.

A guide to defining and testing the important concepts and relationships in a software project's subject area, then recording the agreed vocabulary and decisions.

In plain words
What is it for?
Use it to refine a domain model, settle terminology, test it against scenarios, update CONTEXT.md, and record difficult or important decisions in ADRs.
Why use it?
It prevents teammates and code from using the same words in different ways, especially when edge cases expose unclear concepts.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present.

Part of the engineering-skills plugin — 47 skills, 1 hook shipped together

Good fit Use it to refine a domain model, settle terminology, test it against scenarios, update CONTEXT.md, and record difficult or important decisions in ADRs.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/int2t05/engineering-skills/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 int2t05/engineering-skills --skill domain-modeling
Clone the repo
git clone --depth 1 https://github.com/int2t05/engineering-skills

Made for: Claude Code, Codex.

Or install engineering-skills, the plugin that ships this one along with the rest of its 47 skills, 1 hook.

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/int2t05/engineering-skills/domain-modeling/github.svg)](https://agentmods.dev/skills/int2t05/engineering-skills/domain-modeling)
Your own site
<a href="https://agentmods.dev/skills/int2t05/engineering-skills/domain-modeling"><img src="https://agentmods.dev/badge/skills/int2t05/engineering-skills/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/int2t05/engineering-skills/domain-modeling"><img src="https://agentmods.dev/badge/skills/int2t05/engineering-skills/domain-modeling.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 311 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.
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 $0.00028 $0.00311
Opus 5.5 $0.00011 $0.00124
Sonnet 5.5 $0.00006 $0.00062
Haiku 4.5 $0.00003 $0.00031

Measured 8d ago against content hash f4d99da41e6b, 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 8d 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.

skills/03-design/domain-modeling/SKILL.md · 36 lines

What it actually says

Domain Modeling

When to use

  • Clarify domain terms, invariants and ownership from real scenarios.

Not for: schema-design for storage; architecture for system boundaries.

Steps

  1. Read existing terminology, requirements, code and decisions; identify ambiguous concepts.

  2. Test terms against normal and exceptional scenarios, specifying invariants and state transitions rather than extracting nouns into entities.

  3. Resolve business ambiguity with the user and update the glossary and affected approved descriptions consistently.

  4. Record only consequential decisions separately; give examples distinguishing similar concepts.

Output: Suggested paths, subject to human audit: CONTEXT.md; optionally docs/design/adr/NNNN-slug.md.

Verify

  • Terms explain actual scenarios and invariants; glossary and implementation agree or discrepancies are explicit.

References

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. 8d ago Changed · -58 lines · -41 tokens per session f4d99da41e6b
  2. 15d ago Changed · +4 lines af598f28a393
  3. 1mo ago First seen · 90 lines · 69 tokens per session scan A a97b8a1c0da5

Subscribe to this mod's changes

domain-modeling is a skill published in the GitHub repository int2t05/engineering-skills (3 stars, last pushed 9d ago), licensed MIT. It adds 28 tokens to every session and 311 once invoked, about $0.0001 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 2026-08-31.

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