trove-typescript

TypeScript rules for describing data precisely so the compiler can catch invalid combinations before the program runs.

In plain words
What is it for?
Use it in TypeScript files to model states, validate incoming data, check identifiers, and ensure every possible case is handled.
Why use it?
They reduce unsafe type casts and unchecked external data, making errors easier to find while code is being written.

Cursor rule

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 rules/bravew/trove/trove-typescript
Clone the repo
git clone --depth 1 https://github.com/bravew/trove
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 721 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.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00721
Opus 5 $0.00000 $0.00360
Sonnet 5 $0.00000 $0.00144
Haiku 4.5 $0.00000 $0.00072

Measured 2d ago against content hash 5c2b4756ea63, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

trove-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.

plugins/trove-dev/rules/trove-typescript.mdc · 63 lines

How it starts

The opening of the file, as written. The whole thing — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Trove · v2026.7.4

Session Init

This skill ships Trove conventions. Prefer existing project patterns over generic best practices when they conflict.

If a sibling skill in this plugin matches the request more directly, defer to it. See AGENTS.md (or docs/routing.md in the marketplace) for the per-plugin routing index.

TypeScript Type-System Discipline

The type checker is a proof assistant. Model the domain so wrong states don't compile. On .tsx, defer to trove-react / trove-react-best-practices for component patterns; this skill owns the plain type discipline underneath them.

Core rules

Rule Do Not
Illegal states Discriminated union with a kind/status tag boolean + optional field pairs
Identity Branded primitives (string & { readonly __brand: 'UserId' }) bare string for ids
External data unknown + parse at the boundary any
Casts satisfies to check shape while keeping literals as SomeType
Exhaustiveness const _exhaustive: never = x in the default branch unhandled union members
Type guards Guards that actually narrow and are verified x as Foo inside the guard
Derive Types derived from a schema (Zod/valibot infer) hand-kept parallel types

The canonical example

// BAD — admits the meaningless { completed: true, completedAt: undefined }
type Task = { completed: boolean; completedAt?: Date };

// GOOD — the bad state cannot be constructed
type Task =
  | { status: 'open' }
  | { status: 'done'; completedAt: Date };

Boundaries

Validate once, at the edge (network, config, user input). Past the boundary, trust your domain types and keep logic pure. "Parse, don't validate": a parser returns a more precise type or fails; it doesn't just check and discard what it learned.

function parseUser(raw: unknown): User {
  return UserSchema.parse(raw); // unknown -> User, or throws at the boundary
}

Read the full file on GitHub · 63 lines

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.

  1. 2d ago First seen · 63 lines · 721 tokens per session scan A 5c2b4756ea63

Subscribe to this mod's changes

trove-typescript is a cursor rule published in the GitHub repository bravew/trove (10 stars, last pushed 3d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 721 tokens. 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.