dto

Rules for designing data transfer objects, or DTOs: objects used to carry data between parts of an application. They cover immutability, naming based on context, validation at system boundaries, mapping, and avoiding public setters.

In plain words
What is it for?
They help define DTO names, keep DTOs unchanged after creation, validate incoming data, map between object types, and restrict direct field updates.
Why use it?
They give developers consistent choices for moving and validating data without allowing accidental changes to shared objects.

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/symkit/bundles-rules/dto
Clone the repo
git clone --depth 1 https://github.com/SymKit/bundles-rules
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 1,988 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.01988
Opus 5 $0.00000 $0.00994
Sonnet 5 $0.00000 $0.00398
Haiku 4.5 $0.00000 $0.00199

Measured yesterday against content hash 623435137060, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dto 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 yesterday.

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.

ai/cursor/rules/dto.mdc · 270 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. yesterday First seen · 270 lines · 0 tokens per session scan A 623435137060

Subscribe to this mod's changes

dto is a cursor rule published in the GitHub repository SymKit/bundles-rules (3 stars, last pushed 5mo ago), with no licence file. It costs nothing until one of its globs matches a file; then it loads 1,988 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.