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 jscraik/Agent-Skills --skill typescriptgit clone --depth 1 https://github.com/jscraik/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/jscraik/agent-skills/typescript)<a href="https://agentmods.dev/skills/jscraik/agent-skills/typescript"><img src="https://agentmods.dev/badge/skills/jscraik/agent-skills/typescript.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00026 | $0.00637 |
| Opus 5 | $0.00013 | $0.00318 |
| Sonnet 5 | $0.00005 | $0.00127 |
| Haiku 4.5 | $0.00003 | $0.00064 |
Grade A, and why
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 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 — 105 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Table of Contents
- When to use
- Required inputs
- Deliverables
- Type Safety
- Module Boundaries
- Examples
- Failure mode
- Gotchas
When to use
- Use for TypeScript code authoring or review.
- Use when strict typing and API contracts need hardening.
Required inputs
- Target files or module scope.
- Runtime constraints (Node/browser/edge).
- Existing type errors or contract requirements.
Deliverables
- Type-safe implementation changes.
- Explicitly typed exported surfaces.
- Notes for any unavoidable tradeoffs.
Type Safety
-
Avoid
any; model unknown values with guards and narrow types. -
Prefer explicit return types on exported functions.
-
Use discriminated unions for stateful workflows.
-
Redact secrets, tokens, credentials, and sensitive data by default.
Module Boundaries
- Prefer named exports over default exports in shared modules.
- Keep runtime validation close to IO boundaries.
- Avoid barrel files when they obscure ownership.
Examples
export function parsePort(value: string): number {
const parsed = Number.parseInt(value, 10)
if (Number.isNaN(parsed)) throw new Error(`Invalid port: ${value}`)
return parsed
}
Failure mode
- If domain types are unclear, pause and request schema clarification.
Gotchas
- Casting with
as unknown ashides real typing defects.
See Also
| Skill | When to use |
|---|---|
| [[javascript-pro]] | Base JavaScript patterns when runtime compatibility and async flow need attention |
| [[biome-linting]] | Enforce TypeScript lint and format rules with Biome |
Topic map: [[agent-ops]]
Philosophy
- Optimize for clear, verifiable outcomes with the minimum necessary changes.
- Keep guidance deterministic so repeated runs produce consistent decisions.
Procedure
- Confirm scope, constraints, and required inputs before edits.
- Apply focused changes tied directly to the requested outcome.
- Re-run the highest-signal validations and capture concrete evidence.
What ships with it
4 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.
- 4d ago First seen · 105 lines · 26 tokens per session scan A 8d75fdb799f5
typescript is a skill published in the GitHub repository jscraik/Agent-Skills (8 stars, last pushed 6d ago), licensed Apache-2.0. It adds 26 tokens to every session and 637 once invoked, about $0.0001 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 2026-09-03.
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