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 agentmods add skills/rstackjs/agent-skills/rslib-modern-packagenpx skills add rstackjs/agent-skills --skill rslib-modern-packagegit clone --depth 1 https://github.com/rstackjs/agent-skillsWrote 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/rstackjs/agent-skills/rslib-modern-package)<a href="https://agentmods.dev/skills/rstackjs/agent-skills/rslib-modern-package"><img src="https://agentmods.dev/badge/skills/rstackjs/agent-skills/rslib-modern-package.svg" alt="Measured on agentmods" 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 | $0.00103 | $0.02966 |
| Opus 5 | $0.00051 | $0.01483 |
| Sonnet 5 | $0.00021 | $0.00593 |
| Haiku 4.5 | $0.00010 | $0.00297 |
Grade A, and why
rslib-modern-package 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.
How it starts
The opening of the file, as written. The whole thing — 174 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Rslib Modern Package
Use this skill when creating a new Rslib library, modernizing an existing JS/TS package, or reviewing a package against an opinionated modern library standard.
This skill is opinionated: it describes a recommended modern package contract and may suggest breaking changes when they make the package simpler, safer, and easier for modern consumers.
Standard
Default recommendation for new JS/TS libraries:
- ESM-first, preferably pure ESM.
- Strict TypeScript and correct declaration files.
- Explicit public API through
package.json#exports. - Small named-export API surface.
- Few runtime dependencies, without treating zero dependencies as a religion.
- Small, tree-shakeable output with accurate
sideEffects. - Clear dependency placement: runtime dependencies, peer dependencies, optional dependencies, and dev dependencies are not interchangeable.
- Published package is tested as an artifact, not just as source files.
- Release flow is automated, traceable, and SemVer-aware.
- README.md explains usage for humans; AGENTS.md preserves package invariants for future agents.
Workflow
-
Inspect the package contract first
- Read
package.json, lockfile/package manager,rslib.config.*,tsconfig*, CI/release config, README.md, AGENTS.md, and existingdistoutput. - Identify package kind: Node utility, browser library, isomorphic utility, CLI, UI/component library, framework plugin, SDK, or adapter.
- List supported runtimes, current entry points, deep imports, runtime dependencies, peer dependencies, optional integrations, files with side effects, and published files.
- Run
npm pack --dry-runearly when changing package shape so the real tarball contents guide the review.
- Read
-
Define target environments explicitly
- Do not say "supports modern environments" without defining them.
- Verify the current Node.js release schedule before choosing
engines. - As of May 9, 2026, Node.js 22 and 24 are LTS, and Node.js 20 is EOL. For new Node-facing packages, recommend
engines.node >=22unless real consumers need an older runtime. - Browser packages should state whether they require native ESM, a bundler, Workers support, SSR compatibility, DOM APIs, CSS processing, or specific browser baselines.
- Compatibility drops are breaking changes: old Node/browser versions, undocumented deep imports, default/named export shape, bundled vs external dependency behavior, and import side effects.
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.
- 4d ago First seen · 174 lines · 103 tokens per session scan A beb09a1f030c
rslib-modern-package is a skill published in the GitHub repository rstackjs/agent-skills (92 stars, last pushed yesterday), licensed MIT. It adds 103 tokens to every session and 2,966 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 2026-08-30.
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