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 booklib-ai/booklib --skill effective-typescriptgit clone --depth 1 https://github.com/booklib-ai/booklibWrote 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/booklib-ai/booklib/effective-typescript)<a href="https://agentmods.dev/skills/booklib-ai/booklib/effective-typescript"><img src="https://agentmods.dev/badge/skills/booklib-ai/booklib/effective-typescript/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/booklib-ai/booklib/effective-typescript"><img src="https://agentmods.dev/badge/skills/booklib-ai/booklib/effective-typescript.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 | $0.00101 | $0.03446 |
| Opus 5.5 | $0.00040 | $0.01378 |
| Sonnet 5.5 | $0.00020 | $0.00689 |
| Haiku 4.5 | $0.00010 | $0.00345 |
Grade A, and why
effective-typescript 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 1mo 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 — 263 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Effective TypeScript Skill
Apply the 62 items from Dan Vanderkam's "Effective TypeScript" to review existing code and write new TypeScript. This skill operates in two modes: Review Mode (analyze code for violations) and Write Mode (produce idiomatic, well-typed TypeScript from scratch).
Reference Files
This skill includes categorized reference files covering all 62 items:
ref-01-getting-to-know-ts.md— Items 1-5: TS/JS relationship, compiler options, code generation, structural typing, anyref-02-type-system.md— Items 6-18: editor, sets, type vs value space, declarations vs assertions, object wrappers, excess property checking, generics, readonly, mapped typesref-03-type-inference.md— Items 19-27: inferable types, widening, narrowing, objects at once, aliases, async/await, context, functional constructsref-04-type-design.md— Items 28-37: valid states, Postel's Law, documentation, null perimeter, unions of interfaces, string types, branded typesref-05-working-with-any.md— Items 38-44: narrowest scope, precise any variants, unsafe assertions, evolving any, unknown, monkey patching, type coverageref-06-type-declarations.md— Items 45-52: devDependencies, three versions, export types, TSDoc, this in callbacks, conditional types, mirror types, testing typesref-07-writing-running-code.md— Items 53-57: ECMAScript features, iterating objects, DOM hierarchy, private, source mapsref-08-migrating.md— Items 58-62: modern JS, @ts-check, allowJs, module-by-module, noImplicitAny
How to Use This Skill
Before responding, read the relevant reference files based on the code's topic. For a general review, read all files. For targeted work (e.g., type design), read the specific reference (e.g., ref-04-type-design.md).
Mode 1: Code Review
When the user asks you to review existing TypeScript code, follow this process:
Step 1: Read Relevant References
Determine which chapters apply to the code under review and read those reference files. If unsure, read all of them.
What ships with it
8 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.
- 1mo ago First seen · 263 lines · 101 tokens per session scan A 9997d669da45
effective-typescript is a skill published in the GitHub repository booklib-ai/booklib (39 stars, last pushed 6mo ago), licensed MIT. It adds 101 tokens to every session and 3,446 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 2026-08-30.
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