Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/oborchers/fractional-ctonpx agentmods add skills/oborchers/fractional-cto/typescript-pedantryWrote 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/oborchers/fractional-cto/typescript-pedantry)<a href="https://agentmods.dev/skills/oborchers/fractional-cto/typescript-pedantry"><img src="https://agentmods.dev/badge/skills/oborchers/fractional-cto/typescript-pedantry/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/oborchers/fractional-cto/typescript-pedantry"><img src="https://agentmods.dev/badge/skills/oborchers/fractional-cto/typescript-pedantry.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 | $0.00070 | $0.03494 |
| Opus 5.5 | $0.00028 | $0.01398 |
| Sonnet 5.5 | $0.00014 | $0.00699 |
| Haiku 4.5 | $0.00007 | $0.00349 |
Grade A, and why
typescript-pedantry 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 5d 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 — 373 lines — stays where its author put it; the contents beside it link to each section on GitHub.
TypeScript Is Not "JavaScript With Types Sprinkled On"
TypeScript has a type system powerful enough to catch entire categories of bugs at compile time. But only if you use it. strict: true is the bare minimum, not the finish line. as casts are not type safety -- they are escape hatches that undermine the entire point of using TypeScript. Zod schemas validate at runtime what TypeScript validates at compile time. Discriminated unions make impossible states unrepresentable. If your TypeScript code uses any, type assertions, or unchecked casts, you are writing JavaScript with extra syntax and calling it type-safe.
Strict tsconfig: The Non-Negotiable Baseline
strict: true enables a bundle of checks. It is the starting point, not the goal. These additional flags catch real bugs that strict alone misses:
// tsconfig.json
{
"compilerOptions": {
"strict": true,
"noUncheckedIndexedAccess": true,
"exactOptionalPropertyTypes": true,
"noPropertyAccessFromIndexSignature": true,
"noFallthroughCasesInSwitch": true,
"forceConsistentCasingInFileNames": true,
"verbatimModuleSyntax": true
}
}
| Flag | What It Catches |
|---|---|
strict |
Enables strictNullChecks, strictFunctionTypes, strictBindCallApply, strictPropertyInitialization, noImplicitAny, noImplicitThis, alwaysStrict, useUnknownInCatchVariables |
noUncheckedIndexedAccess |
array[0] returns T | undefined, not T -- forces null checks after indexing |
exactOptionalPropertyTypes |
{ name?: string } means name is string | undefined, NOT string | undefined | null -- prevents assigning undefined explicitly |
noPropertyAccessFromIndexSignature |
Forces bracket notation for index signatures: obj["key"] not obj.key -- makes it clear the property may not exist |
noFallthroughCasesInSwitch |
Prevents missing break in switch cases |
forceConsistentCasingInFileNames |
Prevents import from './User' when the file is user.ts -- catches bugs on case-insensitive filesystems |
verbatimModuleSyntax |
Requires import type for type-only imports -- cleaner output, clearer intent |
What ships with it
2 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.
- 5d ago First seen · 373 lines · 70 tokens per session scan A ecbe809b79d5
typescript-pedantry is a skill published in the GitHub repository oborchers/fractional-cto (32 stars, last pushed 5d ago), licensed MIT. It adds 70 tokens to every session and 3,494 once invoked, about $0.0003 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 2026-10-13.
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