How do I install the Strict Typescript skill?

Run npx skillmds@latest add jagreehal/strict-typescript in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Strict Typescript safe to use?

This skill has not completed SkillMD's automated safety review yet. Capability flags: docs only. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Strict Typescript?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Strict Typescript free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Strict Typescript?

jagreehal (@jagreehal) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Strict Typescript by jagreehal — Agent Skill

Name: Strict Typescript
Rating: 4.5 (4 reviews)
Author: jagreehal

Strict Typescript

Configures and applies strict TypeScript safety (tsconfig flags, ts-reset, narrowing, exhaustive checks). Use this skill when tightening compiler options, eliminating unsafe patterns, or reviewing type-safety gaps. Do not use when/for runtime Zod validation at boundaries (use validation-boundary) or general design review (use design-principles).

jagreehal Updated Sep 10, 2026

File contents

Strict TypeScript

Critical rules

strict: true is the floor. Also enable noUncheckedIndexedAccess, exactOptionalPropertyTypes, verbatimModuleSyntax, erasableSyntaxOnly, and related unused/fallthrough flags.
Ban any / as / non-null assertions in source. Narrow with guards, discriminated unions, or Zod.
Install @total-typescript/ts-reset so JSON.parse is unknown.
Prefer satisfies and as const over loose object typing; avoid barrels and erasable-syntax violations (enum, param properties).
Enforce with @typescript-eslint/strict-type-checked at 'error'.
Before editing tsconfig or patterns, read references/tsconfig.md and references/type-patterns.md.

Workflow

Audit tsconfig.json against the required flags in references/tsconfig.md.
Add reset.d.ts importing @total-typescript/ts-reset.
Enable strict ESLint type-checked rules — see references/eslint-and-build.md.
Replace as/any with guards, unions, or Zod; brand confusable IDs.
Prefer direct imports over barrels; profile with tsc --extendedDiagnostics if compile is slow.
Confirm tsc --noEmit and ESLint pass clean.

Resources

references/tsconfig.md — required flags and explanations. Read when configuring.
references/type-patterns.md — narrowing, ts-reset, type-fest, branded types. Read when fixing unsafe code.
references/eslint-and-build.md — ESLint, barrels, build tools, rationalizations. Read when enforcing in CI.

Validation

Supplementary strict flags all enabled
ts-reset installed via reset.d.ts
No any/as in source (fixtures aside); narrowing is typed
satisfies / as const for literal configs
Strict type-checked ESLint rules are 'error'
No hot-path barrel files; tsc --noEmit clean

Constraints

Prototypes may trade safety for speed; runtime input parsing belongs in validation-boundary.
Related: pattern-enforcement, validation-boundary, fn-args-deps, result-types.

---name: strict-typescriptdescription: Configures and applies strict TypeScript safety (tsconfig flags, ts-reset, narrowing, exhaustive checks). Use this skill when tightening compiler options, eliminating unsafe patterns, or reviewing type-safety gaps. Do not use when/for runtime Zod validation at boundaries (use validation-boundary) or general design review (use design-principles).---# Strict TypeScript## Critical rules- `strict: true` is the floor. Also enable `noUncheckedIndexedAccess`, `exactOptionalPropertyTypes`, `verbatimModuleSyntax`, `erasableSyntaxOnly`, and related unused/fallthrough flags.- Ban `any` / `as` / non-null assertions in source. Narrow with guards, discriminated unions, or Zod.- Install `@total-typescript/ts-reset` so `JSON.parse` is `unknown`.- Prefer `satisfies` and `as const` over loose object typing; avoid barrels and erasable-syntax violations (`enum`, param properties).- Enforce with `@typescript-eslint/strict-type-checked` at `'error'`.- Before editing tsconfig or patterns, read [references/tsconfig.md](references/tsconfig.md) and [references/type-patterns.md](references/type-patterns.md).## Workflow1. Audit `tsconfig.json` against the required flags in [references/tsconfig.md](references/tsconfig.md).2. Add `reset.d.ts` importing `@total-typescript/ts-reset`.3. Enable strict ESLint type-checked rules — see [references/eslint-and-build.md](references/eslint-and-build.md).4. Replace `as`/`any` with guards, unions, or Zod; brand confusable IDs.5. Prefer direct imports over barrels; profile with `tsc --extendedDiagnostics` if compile is slow.6. Confirm `tsc --noEmit` and ESLint pass clean.## Resources- [references/tsconfig.md](references/tsconfig.md) — required flags and explanations. Read when configuring.- [references/type-patterns.md](references/type-patterns.md) — narrowing, ts-reset, type-fest, branded types. Read when fixing unsafe code.- [references/eslint-and-build.md](references/eslint-and-build.md) — ESLint, barrels, build tools, rationalizations. Read when enforcing in CI.## Validation- [ ] Supplementary strict flags all enabled- [ ] `ts-reset` installed via `reset.d.ts`- [ ] No `any`/`as` in source (fixtures aside); narrowing is typed- [ ] `satisfies` / `as const` for literal configs- [ ] Strict type-checked ESLint rules are `'error'`- [ ] No hot-path barrel files; `tsc --noEmit` clean## Constraints- Prototypes may trade safety for speed; runtime input parsing belongs in `validation-boundary`.- Related: `pattern-enforcement`, `validation-boundary`, `fn-args-deps`, `result-types`.

Frequently asked questions