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 pproenca/dot-skills --skill migrate-js-to-modern-typescriptgit clone --depth 1 https://github.com/pproenca/dot-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/pproenca/dot-skills/migrate-js-to-modern-typescript)<a href="https://agentmods.dev/skills/pproenca/dot-skills/migrate-js-to-modern-typescript"><img src="https://agentmods.dev/badge/skills/pproenca/dot-skills/migrate-js-to-modern-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/pproenca/dot-skills/migrate-js-to-modern-typescript"><img src="https://agentmods.dev/badge/skills/pproenca/dot-skills/migrate-js-to-modern-typescript.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00186 | $0.02208 |
| Opus 5 | $0.00093 | $0.01104 |
| Sonnet 5 | $0.00037 | $0.00442 |
| Haiku 4.5 | $0.00019 | $0.00221 |
Grade A, and why
migrate-js-to-modern-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 6d 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 — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.
JavaScript to TypeScript Migration Best Practices
Guide for taking a JavaScript codebase to strict, modern TypeScript without a big-bang rewrite. Contains 42 rules across 7 categories, prioritized by impact to drive an incremental, file-by-file migration that keeps the build compiling at every step.
When to Apply
Reference these guidelines when:
- Converting a
.jscodebase to.ts(whole project or one module at a time) - Adding types to existing JavaScript via JSDoc or annotations
- Choosing a
tsconfigandallowJsstrategy for a mixed JS/TS repo - Turning on
strictmode or individual strict flags on a large codebase - Replacing
any,ascasts, and!assertions left over from a quick conversion - Validating external data (JSON, env, API responses) so the types you wrote are true at runtime
- Converting CommonJS to ESM, prototypes to classes, and other JS idioms to TS
- Updating the build, runner, and CI to type-check and publish TypeScript
How the Migration Flows
tsconfig & strategy → strictness ratchet → type the surfaces → kill any/casts
→ validate runtime boundaries → convert JS idioms → tooling/build/CI
Decisions at the front cascade: a wrong tsconfig or a top-down conversion order forces you to re-type modules twice, and an early any flood poisons everything downstream. Work from the front of this pipeline and from the leaves of the dependency graph inward.
Rule Categories by Priority
| Priority | Category | Impact | Prefix |
|---|---|---|---|
| 1 | Migration Setup & tsconfig | CRITICAL | setup- |
| 2 | Strictness Ratcheting | CRITICAL | strict- |
| 3 | Typing Public Surfaces | HIGH | surface- |
| 4 | Replacing any & Unsafe Casts |
HIGH | unsafe- |
| 5 | Runtime Data Validation | MEDIUM-HIGH | runtime- |
| 6 | JS-to-TS Idiom Conversion | MEDIUM | idiom- |
| 7 | Tooling & Build Migration | LOW-MEDIUM | tooling- |
Quick Reference
1. Migration Setup & tsconfig (CRITICAL)
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.
- AGENTS.md 9.4 KB
- assets/templates/_template.md 1.2 KB
- metadata.json 1.2 KB
- references/_sections.md 2.4 KB
- references/idiom-default-export-to-named.md 1.2 KB
- references/idiom-enum-to-union-or-const.md 1.4 KB
- references/idiom-optional-chaining-over-guards.md 1.2 KB
- references/idiom-prototype-to-class.md 1.2 KB
- references/idiom-replace-arguments-object.md 1.1 KB
- references/idiom-require-to-import.md 1.1 KB
- references/idiom-type-only-imports.md 1.3 KB
- references/runtime-derive-types-from-schemas.md 1.2 KB
- references/runtime-type-environment-variables.md 1.3 KB
- references/runtime-type-guards-at-boundaries.md 1.5 KB
- references/runtime-type-json-parse.md 1.2 KB
- references/runtime-validate-external-data.md 1.3 KB
- references/setup-allowjs-checkjs-bridge.md 1.5 KB
- references/setup-jsdoc-before-rename.md 1.4 KB
- references/setup-migrate-leaves-first.md 1.6 KB
- references/setup-modern-module-resolution.md 1.4 KB
- references/setup-noemitonerror-isolatedmodules.md 1.2 KB
- references/setup-prefer-ts-expect-error.md 1.4 KB
- references/setup-skiplibcheck-during-migration.md 1.4 KB
- references/strict-enable-flags-incrementally.md 1.3 KB
- references/strict-exact-optional-property-types.md 1.4 KB
- references/strict-no-implicit-any.md 1.1 KB
- references/strict-no-unchecked-indexed-access.md 1.5 KB
- references/strict-prioritize-null-checks.md 1.3 KB
- references/strict-use-unknown-in-catch.md 1.1 KB
- references/surface-annotate-exported-signatures.md 1.3 KB
- references/surface-interface-for-object-args.md 1.2 KB
- references/surface-replace-jsdoc-with-types.md 1.2 KB
- references/surface-type-callbacks.md 1.2 KB
- references/surface-type-class-fields.md 1.3 KB
- references/surface-type-default-params.md 1.2 KB
- references/tooling-declare-untyped-modules.md 1.3 KB
- references/tooling-emit-declaration-files.md 1.2 KB
- references/tooling-install-types-packages.md 1.1 KB
- references/tooling-typecheck-in-ci.md 1.1 KB
- references/tooling-use-tsx-over-ts-node.md 1.2 KB
- references/unsafe-avoid-double-assertion.md 1.2 KB
- references/unsafe-eliminate-as-casts.md 1.2 KB
- references/unsafe-narrow-instead-of-nonnull.md 1.3 KB
- references/unsafe-prefer-unknown-over-any.md 1.3 KB
- references/unsafe-replace-function-type.md 1.3 KB
- references/unsafe-type-dynamic-property-access.md 1.3 KB
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.
- 6d ago First seen · 126 lines · 186 tokens per session scan A 313b8badea1f
migrate-js-to-modern-typescript is a skill published in the GitHub repository pproenca/dot-skills (206 stars, last pushed 25d ago), licensed MIT. It adds 186 tokens to every session and 2,208 once invoked, about $0.0009 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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