A set of guidelines for writing safer and faster TypeScript, a programming language that adds types to JavaScript. It covers the compiler, type checking, asynchronous code, imports, and type definitions.

Use it when changing .ts, .tsx, or .d.ts files, tuning tsconfig or tsc, organizing modules, improving Promise-based code, or fixing type-safety issues.

It helps address slow builds, type errors, unsafe values, memory problems, and hard-to-maintain code without focusing on beginner TypeScript lessons or a particular framework.

typescript — Skill by PlunderStruck

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/plunderstruck/scip-query/typescript

Any agent

npx skills add PlunderStruck/scip-query --skill typescript

Clone the repo

git clone --depth 1 https://github.com/PlunderStruck/scip-query

Made for: Claude Code, Codex.

Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 858 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.

Model	Per session	Once invoked
Fable 5	$0.00057	$0.00858
Opus 5	$0.00028	$0.00429
Sonnet 5	$0.00011	$0.00172
Haiku 4.5	$0.00006	$0.00086

Measured 2d ago against content hash 4e7abd3ecd51, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 2d 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.

.agents/skills/typescript/SKILL.md · 92 lines

How it starts

The opening of the file, as written. The whole thing — 92 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TypeScript Best Practices

Use this skill as a compact router to the TypeScript rule pack. A TypeScript rule is a narrow, evidence-backed coding guideline whose purpose is to improve compile speed, runtime behavior, type safety, or maintainability for TypeScript projects.

The full compiled document is AGENTS.md. Individual detailed rules live under references/.

Rules

Start with the highest-impact category that matches the work.
Read the specific reference file before applying a non-obvious rule.
Prefer project conventions when a rule conflicts with established local architecture.
Verify with the project typecheck, test, or build command after edits.

Priority	Category	Use for	Prefix
1	Type system performance	slow type checking, complex types, exported APIs	`type-`
2	Compiler configuration	tsconfig, project references, included files	`tscfg-`
3	Async patterns	Promise concurrency, async wrappers, return types	`async-`
4	Module organization	imports, barrels, dynamic imports, @types scope	`module-`
5	Type safety	unknown, guards, exhaustive checks, nullability	`safety-`
6	Memory management	timers, listeners, closures, global caches	`mem-`
7	Runtime optimization	hot loops, lookups, object spread, string methods	`runtime-`
8	Advanced patterns	branded types, satisfies, template literal types	`advanced-`

Quick Map

Type system:

type-interfaces-over-intersections
type-avoid-large-unions
type-extract-conditional-types
type-limit-recursion-depth
type-explicit-return-types
type-avoid-deep-generics
type-simplify-mapped-types

Compiler:

tscfg-enable-incremental
tscfg-skip-lib-check
tscfg-isolate-modules
tscfg-project-references
tscfg-exclude-properly
tscfg-strict-function-types

Async and modules:

async-parallel-promises
async-defer-await
async-avoid-loop-await
async-explicit-return-types
async-avoid-unnecessary-async
module-avoid-barrel-imports
module-avoid-circular-dependencies
module-use-type-imports
module-dynamic-imports
module-control-types-inclusion

Read the full file on GitHub · 92 lines

Files

What ships with it

46 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.

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.

2d ago First seen · 92 lines · 57 tokens per session scan A 4e7abd3ecd51

Subscribe to this mod's changes

typescript is a skill published in the GitHub repository PlunderStruck/scip-query (5 stars, last pushed 2d ago), licensed Apache-2.0. It adds 57 tokens to every session and 858 once invoked, about $0.0003 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 2026-08-31.

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