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 metaprogramming-rlanggit 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/metaprogramming-rlang)<a href="https://agentmods.dev/skills/justanesta/claude-code-resources/metaprogramming-rlang"><img src="https://agentmods.dev/badge/skills/justanesta/claude-code-resources/metaprogramming-rlang/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/metaprogramming-rlang"><img src="https://agentmods.dev/badge/skills/justanesta/claude-code-resources/metaprogramming-rlang.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 | $0.01065 |
| Opus 5.5 | $0.00037 | $0.00426 |
| Sonnet 5.5 | $0.00019 | $0.00213 |
| Haiku 4.5 | $0.00009 | $0.00106 |
Grade A, and why
metaprogramming-rlang 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 2mo 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 — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Metaprogramming rlang
This skill covers modern rlang patterns for data-masking, tidy evaluation, and building programmatic tidyverse functions.
Core Concepts
Data-masking allows R expressions to refer to data frame columns as if they were variables in the environment. rlang provides the metaprogramming framework that powers tidyverse data-masking.
Key rlang Tools
- Embracing
{{}}- Forward function arguments to data-masking functions - Injection
!!- Inject single expressions or values - Splicing
!!!- Inject multiple arguments from a list - Dynamic dots - Programmable
...with injection support - Pronouns
.data/.env- Explicit disambiguation between data and environment variables
When to Use Each Operator
| Operator | Use Case | Example |
|---|---|---|
{{ }} |
Forward function arguments | summarise(mean = mean({{ var }})) |
!! |
Inject single expression/value | summarise(mean = mean(!!sym(var))) |
!!! |
Inject multiple arguments | group_by(!!!syms(vars)) |
.data[[]] |
Access columns by name | mean(.data[[var]]) |
Function Argument Patterns
Forwarding with {{}}
Use {{}} to forward function arguments to data-masking functions. See embrace-examples.md.
Forwarding ...
No special syntax needed for dots forwarding. See dots-forwarding.md.
Names Patterns with .data
Use .data pronoun for programmatic column access. See data-pronoun-examples.md.
Injection Operators
Advanced Injection with !!
Create symbols from strings, inject values to avoid name collisions. See injection-examples.md.
Splicing with !!!
Inject multiple symbols from character vectors, splice lists of arguments. See splicing-examples.md.
Dynamic Dots Patterns
Using list2() for Dynamic Dots Support
What ships with it
12 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.
- references/avoid-patterns.md 1.1 KB
- references/bridge-patterns.md 481 B
- references/data-pronoun-examples.md 506 B
- references/dots-forwarding.md 415 B
- references/dynamic-dots-examples.md 439 B
- references/embrace-examples.md 410 B
- references/injection-examples.md 415 B
- references/name-injection-examples.md 650 B
- references/pronouns-examples.md 520 B
- references/splicing-examples.md 370 B
- references/testing-examples.md 491 B
- references/transformation-patterns.md 556 B
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.
- 2mo ago First seen · 125 lines · 93 tokens per session scan A 6bd2e043792a
metaprogramming-rlang is a skill published in the GitHub repository justanesta/claude-code-resources (2 stars, last pushed 6mo ago), licensed MIT. It adds 93 tokens to every session and 1,065 once invoked, about $0.0004 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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