avoid-nested-code-blocks

A rule for writing blog posts in Markdown or MDX, a Markdown format that supports interactive components. It forbids placing one triple-backtick code block inside another.

In plain words
What is it for?
Use it when adding code examples to Markdown or MDX blog posts, particularly examples that contain their own fenced code blocks.
Why use it?
Nested code fences can make an MDX blog fail to build. The rule provides safer ways to show code inside code examples.

Cursor rule for Cursor

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/jeevan-vj/iamjeevan/avoid-nested-code-blocks
Clone the repo
git clone --depth 1 https://github.com/jeevan-vj/iamjeevan

Made for: Cursor.

Per session 114 This file is loaded in full into every session.
When invoked 114 The same file — it is already loaded in full.
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 $0.00114 $0.00114
Opus 5 $0.00057 $0.00057
Sonnet 5 $0.00023 $0.00023
Haiku 4.5 $0.00011 $0.00011

Measured yesterday against content hash a9fcbe725bb7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

avoid-nested-code-blocks 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.

.cursor/rules/avoid-nested-code-blocks.mdc · 12 lines

What it actually says

Avoid Nested Code Blocks in Blog Posts

  • Do NOT use triple backticks (```) inside another triple backtick code block in any markdown/MDX blog post.
  • MDX does not support nested code fences and this will cause build errors.
  • If you need to show code-within-code, use 4-space indentation for the inner code, or use a single code block and clearly comment or separate the sections.

See README.md for more details. description: globs: alwaysApply: false

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 · 12 lines · 114 tokens per session scan A a9fcbe725bb7

Subscribe to this mod's changes

avoid-nested-code-blocks is a cursor rule published in the GitHub repository jeevan-vj/iamjeevan (3 stars, last pushed 3mo ago), licensed MIT. It adds 114 tokens to every session, about $0.0006 per session on Opus 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 2026-08-31.