domain-modeling

domain-modeling is a skill for Claude Code, Codex from stevesolun/ctx. It costs 42 tokens per session (326 once invoked), scanned A, original, MIT.

A method for defining what important concepts mean, how they relate, and where the boundaries between parts of a system belong.

In plain words
What is it for?
It helps clarify terminology, test definitions with examples and edge cases, compare the model with the code, and record durable decisions when needed.
Why use it?
It removes ambiguity when people use the same word in different ways or when unclear concepts could lead to a poor design.

Skill for Claude CodeCodex

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.

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

Made for: Claude Code, Codex.

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/stevesolun/ctx/domain-modeling.svg)](https://agentmods.dev/skills/stevesolun/ctx/domain-modeling)
Your own site
<a href="https://agentmods.dev/skills/stevesolun/ctx/domain-modeling"><img src="https://agentmods.dev/badge/skills/stevesolun/ctx/domain-modeling.svg" alt="Measured on agentmods" 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 326 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00042 $0.00326
Opus 5 $0.00021 $0.00163
Sonnet 5 $0.00008 $0.00065
Haiku 4.5 $0.00004 $0.00033

Measured 5d ago against content hash acf707b820e8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 5d 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.

.agents/skills/domain-modeling/SKILL.md · 39 lines

What it actually says

Model the domain

Build a precise shared understanding of the concepts that matter to the current decision. Read existing glossaries, context maps, ADRs, code, and tests when they provide relevant evidence.

Sharpen the model

  • Identify overloaded terms, hidden distinctions, and conflicting definitions.
  • Use concrete scenarios and edge cases to test whether concepts and boundaries hold.
  • Compare the stated model with behavior in the code and surface material contradictions.
  • Propose clear language when ambiguity is blocking progress, while respecting established repository terminology that remains accurate.

Ask the user to resolve a term only when their intent cannot be inferred safely and the distinction affects the outcome.

Record durable knowledge proportionally

Update a glossary or context map when the user requests it or when a resolved term is durable, project-specific, and useful beyond the current conversation. Follow an existing repository format first; otherwise use the context format as a lightweight starting point.

Record an ADR only when a decision is costly to reverse, surprising without its context, and based on a meaningful tradeoff. Follow existing ADR conventions or use the ADR format. Do not create artifacts merely to complete the workflow.

Keep domain definitions separate from implementation plans. Report unresolved ambiguity and artifact changes explicitly.

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. 5d ago First seen · 39 lines · 42 tokens per session scan A acf707b820e8

Subscribe to this mod's changes

domain-modeling is a skill published in the GitHub repository stevesolun/ctx (583 stars, last pushed 4d ago), licensed MIT. It adds 42 tokens to every session and 326 once invoked, about $0.0002 per session on Opus 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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