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.
npx skills add justanesta/claude-code-resources --skill designing-oop-rgit clone --depth 1 https://github.com/justanesta/claude-code-resourcesWrote 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.
[](https://agentmods.dev/skills/justanesta/claude-code-resources/designing-oop-r)<a href="https://agentmods.dev/skills/justanesta/claude-code-resources/designing-oop-r"><img src="https://agentmods.dev/badge/skills/justanesta/claude-code-resources/designing-oop-r/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.
<a href="https://agentmods.dev/skills/justanesta/claude-code-resources/designing-oop-r"><img src="https://agentmods.dev/badge/skills/justanesta/claude-code-resources/designing-oop-r.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00093 | $0.00975 |
| Opus 5 | $0.00046 | $0.00487 |
| Sonnet 5 | $0.00019 | $0.00195 |
| Haiku 4.5 | $0.00009 | $0.00097 |
Grade A, and why
designing-oop-r 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.
How it starts
The opening of the file, as written. The whole thing — 105 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Designing OOP R
This skill covers object-oriented programming in R, including S7, S3, S4, and vctrs-based classes.
Decision Tree: What Are You Building?
1. Vector-like objects (behave like atomic vectors)
Use vctrs when:
- Need data frame integration (columns/rows)
- Want type-stable vector operations
- Building factor-like, date-like, or numeric-like classes
- Need consistent coercion/casting behavior
- Working with existing tidyverse infrastructure
Examples: custom date classes, units, categorical data
2. General objects (complex data structures, not vector-like)
Use S7 when:
- NEW projects that need formal classes
- Want property validation and safe property access (
@) - Need multiple dispatch (beyond S3's double dispatch)
- Converting from S3 and want better structure
- Building class hierarchies with inheritance
- Want better error messages and discoverability
Use S3 when:
- Simple classes with minimal structure needs
- Maximum compatibility and minimal dependencies
- Quick prototyping or internal classes
- Contributing to existing S3-based ecosystems
- Performance is absolutely critical (minimal overhead)
Use S4 when:
- Working in Bioconductor ecosystem
- Need complex multiple inheritance (S7 doesn't support this)
- Existing S4 codebase that works well
S7 vs S3 Comparison
| Feature | S3 | S7 | When S7 wins |
|---|---|---|---|
| Class definition | Informal (convention) | Formal (new_class()) |
Need guaranteed structure |
| Property access | $ or attr() (unsafe) |
@ (safe, validated) |
Property validation matters |
| Validation | Manual, inconsistent | Built-in validators | Data integrity important |
| Method discovery | Hard to find methods | Clear method printing | Developer experience matters |
| Multiple dispatch | Limited (base generics) | Full multiple dispatch | Complex method dispatch needed |
| Inheritance | Informal, NextMethod() |
Explicit super() |
Predictable inheritance needed |
| Migration cost | - | Low (1-2 hours) | Want better structure |
| Performance | Fastest | ~Same as S3 | Performance difference negligible |
| Compatibility | Full S3 | Full S3 + S7 | Need both old and new patterns |
What ships with it
5 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.
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.
- 8d ago First seen · 105 lines · 93 tokens per session scan A c9e08f75bb0c
designing-oop-r is a skill published in the GitHub repository justanesta/claude-code-resources (2 stars, last pushed 4mo ago), licensed MIT. It adds 93 tokens to every session and 975 once invoked, about $0.0005 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 2026-08-31.
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