serializer

A set of rules for building serializers, which turn program data into another format such as JSON. It covers data cleanup, grouping, context, circular references, and choosing formats based on a type or marker.

In plain words
What is it for?
Use it when implementing normalizers, serializer groups, context builders, circular-reference handling, or discriminator maps.
Why use it?
It gives developers a shared way to handle difficult serialization cases. This reduces inconsistent output and problems when objects refer to themselves or need different representations.

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/serializer
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 1,434 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 $0.01434
Opus 5 $0.00000 $0.00717
Sonnet 5 $0.00000 $0.00287
Haiku 4.5 $0.00000 $0.00143

Measured yesterday against content hash 7c6a05b495db, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

serializer 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/serializer.mdc · 217 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 · 217 lines · 0 tokens per session scan A 7c6a05b495db

Subscribe to this mod's changes

serializer 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 1,434 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.