module-boundaries

module-boundaries is a skill for Claude Code, Codex from codybrom/clairvoyance. It costs 70 tokens per session (1,207 once invoked), scanned A, original, MIT.

A review guide for deciding how code should be divided into modules. Modules are separate parts of a codebase that group related responsibilities.

In plain words
What is it for?
Use it when deciding whether to merge or split modules, investigating frequent changes across module boundaries, or reviewing a decomposition decision.
Why use it?
It helps prevent both tightly coupled parts being split apart and small pass-through components creating unnecessary complexity.

Skill for Claude CodeCodex

Part of the clairvoyance plugin — 16 skills, 1 agent shipped together

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/codybrom/clairvoyance/module-boundaries
Any agent
npx skills add codybrom/clairvoyance --skill module-boundaries
Clone the repo
git clone --depth 1 https://github.com/codybrom/clairvoyance

Made for: Claude Code, Codex.

Or install clairvoyance, the plugin that ships this one along with the rest of its 16 skills, 1 agent.

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 module-boundaries

README.md
[![agentmods](https://agentmods.dev/badge/skills/codybrom/clairvoyance/module-boundaries.svg)](https://agentmods.dev/skills/codybrom/clairvoyance/module-boundaries)
Your own site
<a href="https://agentmods.dev/skills/codybrom/clairvoyance/module-boundaries"><img src="https://agentmods.dev/badge/skills/codybrom/clairvoyance/module-boundaries.svg" alt="Measured on agentmods" height="20"></a>
Per session 70 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,207 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 $0.00070 $0.01207
Opus 5 $0.00035 $0.00603
Sonnet 5 $0.00014 $0.00241
Haiku 4.5 $0.00007 $0.00121

Measured 4d ago against content hash b71cbc80defb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

module-boundaries 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 4d 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/module-boundaries/SKILL.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Module Boundaries Review Lens

When invoked with $ARGUMENTS, focus the analysis on the specified file or module. Read the target code first, then apply the checks below.

Evaluate where module boundaries are drawn: are related things together and unrelated things apart?

When to Apply

  • Deciding whether to split a large class or merge small ones
  • When two modules seem tightly coupled
  • When a change to one module frequently requires changes to another
  • When reviewing a decomposition decision

Core Principles

The Default Instinct Is Wrong

Most developers assume smaller is better, which produces systems full of shallow, pass-through components that increase cognitive load without hiding anything. The right answer is always whichever arrangement results in lower overall system complexity. Not smaller. Not more separated. Simpler.

Merge Signals (Better Together)

  • They share information: Same format, protocol, or data structure knowledge
  • They simplify each other: Together, code is simpler than pieces apart
  • They always change together: The boundary is fiction
  • One is incomplete without the other: Callers must always use both
  • It eliminates duplication: The same code appears in both places. Merging lets it exist once
  • It resolves pass-throughs: A forwarding method adds a layer without adding an abstraction

Four costs of every split: more components to track, connective tissue to manage the boundary, separation of related code (producing unknown unknowns) and duplication.

Split Signals (Better Apart)

  • Pieces are independent: Can be understood and modified separately
  • Different knowledge domains: No shared secrets
  • A clear, simple interface exists at the boundary
  • Different rates of change: One stable, one evolving
  • General-purpose from special-purpose: Keep the general-purpose layer clean

The Third Option

When combining doesn't simplify and separating doesn't either, look for the abstraction underneath both. Forcing a merge produces a module with two identities. Forcing a split produces conjoined modules. The relationship between the two things points at a concept that neither one is.

Read the full file on GitHub · 97 lines

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. 4d ago First seen · 97 lines · 70 tokens per session scan A b71cbc80defb

Subscribe to this mod's changes

module-boundaries is a skill published in the GitHub repository codybrom/clairvoyance (12 stars, last pushed 1mo ago), licensed MIT. It adds 70 tokens to every session and 1,207 once invoked, about $0.0003 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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