rslib-best-practices

rslib-best-practices is a skill for Claude Code, Codex from rstackjs/agent-skills. It costs 47 tokens per session (632 once invoked), scanned A, original, MIT.

A set of recommendations for configuring and building JavaScript and TypeScript libraries with Rslib. Rslib is a build tool that packages reusable code for other projects.

In plain words
What is it for?
It covers Rslib configuration, command-line workflows, watch mode, output formats, dependencies, declaration files, and build optimization.
Why use it?
It helps avoid mismatches between package exports, generated code, and TypeScript declaration files, while keeping library builds suitable for their target environment.

Skill for Claude CodeCodex

Part of the rstack plugin — 29 skills 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/rstackjs/agent-skills/rslib-best-practices
Any agent
npx skills add rstackjs/agent-skills --skill rslib-best-practices
Clone the repo
git clone --depth 1 https://github.com/rstackjs/agent-skills

Made for: Claude Code, Codex.

Or install rstack, the plugin that ships this one along with the rest of its 29 skills.

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 rslib-best-practices

README.md
[![agentmods](https://agentmods.dev/badge/skills/rstackjs/agent-skills/rslib-best-practices.svg)](https://agentmods.dev/skills/rstackjs/agent-skills/rslib-best-practices)
Your own site
<a href="https://agentmods.dev/skills/rstackjs/agent-skills/rslib-best-practices"><img src="https://agentmods.dev/badge/skills/rstackjs/agent-skills/rslib-best-practices.svg" alt="Measured on agentmods" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 632 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 $0.00047 $0.00632
Opus 5 $0.00023 $0.00316
Sonnet 5 $0.00009 $0.00126
Haiku 4.5 $0.00005 $0.00063

Measured 4d ago against content hash f4444a526da6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

rslib-best-practices 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.

Origin

Copies of this mod

3 near-identical copies found in the catalogue:

skills/rslib-best-practices/SKILL.md · 59 lines

How it starts

The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Rslib Best Practices

Apply these rules when writing or reviewing Rslib library projects.

Configuration

  • Use rslib.config.ts and defineConfig
  • Check Rslib-specific configurations first (e.g., lib.*), and also leverage Rsbuild configurations (e.g., source.*, output.*, tools.*) as needed
  • For deep-level or advanced configuration needs, use tools.rspack or tools.bundlerChain to access Rspack's native configurations
  • In TypeScript projects, prefer tsconfig.json path aliases

CLI

  • Use rslib to build
  • Use rslib --watch to build in watch mode for local development
  • Use rslib inspect to inspect final Rslib/Rsbuild/Rspack configs

Output

  • Prefer to build pure-ESM package with "type": "module" in package.json
  • Prefer to use bundleless mode with output.target set to 'web' when building component libraries
  • Prefer to use bundle mode when building Node.js utility libraries
  • Ensure exports field in package.json is correctly configured and matches the actual JavaScript output and declaration files output of different formats (ESM, CJS, etc.)

Declaration files

  • Prefer to enable declaration file generation with lib.dts: true or detailed configurations
  • For faster type generation, enable lib.dts.tsgo experimental feature with @typescript/native-preview installed

Dependencies

  • Prefer to place dependencies to be bundled in devDependencies in bundle mode and dependencies in dependencies and peerDependencies will be automatically externalized (not bundled) by default
  • Verify the build output and dependency specifiers in package.json carefully to ensure no missing dependency errors occur when consumers install and use this package

Build optimization

  • Keep syntax target in lib.syntax aligned with real compatibility requirements to enable better optimizations
  • Avoid format-specific APIs in source code for better compatibility with different output formats
  • Prefer lightweight dependencies to reduce bundle size

Read the full file on GitHub · 59 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 · 59 lines · 47 tokens per session scan A f4444a526da6

Subscribe to this mod's changes

rslib-best-practices is a skill published in the GitHub repository rstackjs/agent-skills (92 stars, last pushed 2d ago), licensed MIT. It adds 47 tokens to every session and 632 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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