pn-diagrams

pn-diagrams is a cursor rule for Cursor from perniemann/pnCore. It costs 0 tokens per session (325 once invoked), scanned A, original, MIT.

A set of rules for deciding when and how to create diagrams in Markdown, HTML, or Mermaid. Mermaid is a text format that turns descriptions into diagrams.

In plain words
What is it for?
Use it when adding or editing architecture diagrams, flowcharts, or other Mermaid, Markdown, HTML, or diagram files.
Why use it?
It prevents diagrams that add clutter, use inconsistent visual styles, or become too complicated to read.

Cursor rule for Cursor

Written for Cursor: a Cursor rule (.mdc).

Good fit Use it when adding or editing architecture diagrams, flowcharts, or other Mermaid, Markdown, HTML, or diagram files.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/perniemann/pncore/pn-diagrams
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.

Clone the repo
git clone --depth 1 https://github.com/perniemann/pnCore

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for pn-diagrams

README.md
[![agentmods](https://agentmods.dev/badge/rules/perniemann/pncore/pn-diagrams/github.svg)](https://agentmods.dev/rules/perniemann/pncore/pn-diagrams)
Your own site
<a href="https://agentmods.dev/rules/perniemann/pncore/pn-diagrams"><img src="https://agentmods.dev/badge/rules/perniemann/pncore/pn-diagrams/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for pn-diagrams

Your own site · 80×15
<a href="https://agentmods.dev/rules/perniemann/pncore/pn-diagrams"><img src="https://agentmods.dev/badge/rules/perniemann/pncore/pn-diagrams.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 325 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00000 $0.00325
Opus 5 $0.00000 $0.00162
Sonnet 5 $0.00000 $0.00065
Haiku 4.5 $0.00000 $0.00032

Measured 8d ago against content hash 24c0e83854fc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

pn-diagrams 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 8d 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.

packages/pn-core-mcp/content/rules/pn-diagrams.mdc · 17 lines

What it actually says

Diagrams

Applies when editing markdown, HTML, or .mmd/.mermaid sources.

  1. Would a paragraph or table do the same job? If yes, do not draw. Highest-quality move is deletion.
  2. Load get_skill("pn-diagram-design") (or get_command("pn-diagram")) before drawing. Follow pn-core://reference/diagram-baseline.md when MCP is available.
  3. Pick one visual type and state it. Split above ~9 nodes rather than packing more boxes. Confirm type, size, and planned cuts before drawing.
  4. Mermaid: include accTitle and accDescr. Editorial HTML/SVG: tokens from .pncore-design.md (paper, ink, muted, accent, link); never default to Geist or template cyan/purple.
  5. Accent on 1–2 focals only. Static by default.
  6. Ship gate: emit D-01–D-10 from pn-core://reference/diagram-baseline.md. DIAGRAM: NO-GO → fix before done. /pn-diagram also runs skeptic (and pn-render-verify on editorial HTML).
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. 8d ago First seen · 17 lines · 0 tokens per session scan A 24c0e83854fc

Subscribe to this mod's changes

pn-diagrams is a cursor rule published in the GitHub repository perniemann/pnCore (0 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 325 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.