trpc

A set of coding rules for tRPC, a TypeScript framework for calling server procedures from a client with shared types. It covers routers, validated inputs, procedures, clients, middleware, and errors.

In plain words
What is it for?
Organizing routers, defining queries and mutations, validating inputs with Zod, adding authentication and logging middleware, using typed clients, updating cached data, and handling errors.
Why use it?
It gives a consistent structure for tRPC code and helps prevent missing validation, weak authentication checks, unhandled request states, and accidental exposure of internal errors.

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/nedcodes-ok/cursor-doctor/trpc
Clone the repo
git clone --depth 1 https://github.com/nedcodes-ok/cursor-doctor
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 311 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 $0.00311
Opus 5 $0.00000 $0.00156
Sonnet 5 $0.00000 $0.00062
Haiku 4.5 $0.00000 $0.00031

Measured 2d ago against content hash 84497931e077, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

trpc 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.

pro-kit/templates/tools/trpc.mdc · 35 lines

What it actually says

tRPC Rules

Router Setup

  • Organize routers by domain (userRouter, postRouter, etc.) and merge with appRouter
  • Keep procedure definitions focused — one operation per procedure
  • Use input validation with zod schemas on every procedure
  • Define output types explicitly when the inferred type is complex

Procedures

  • Use query for read operations, mutation for writes
  • Use middleware for cross-cutting concerns (auth, logging, rate limiting)
  • Protect procedures with authentication middleware, not inline checks
  • Keep business logic in separate service functions, not directly in procedures

Client Usage

  • Use the generated typed client — never call procedures with untyped fetch
  • Handle loading and error states for every query (isLoading, isError)
  • Use optimistic updates for mutations that modify displayed data
  • Invalidate related queries after mutations using utils.queryKey.invalidate()

Error Handling

  • Throw TRPCError with appropriate codes (UNAUTHORIZED, NOT_FOUND, BAD_REQUEST)
  • Do not expose internal error details to the client — map to user-friendly messages
  • Log full error details server-side

Anti-patterns

  • Do not create one giant router — split by domain
  • Do not skip input validation — every procedure needs a zod schema
  • Do not mix tRPC calls with raw fetch to the same endpoints
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 · 35 lines · 311 tokens per session scan A 84497931e077

Subscribe to this mod's changes

trpc is a cursor rule published in the GitHub repository nedcodes-ok/cursor-doctor (9 stars, last pushed 5mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 311 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.