acad-plugin

A set of development instructions for building AutoCAD .NET plugins for AutoCAD 2027, Civil 3D, and Plant 3D. It includes project scaffolding and guidance for using those products’ programming interfaces.

In plain words
What is it for?
Creating and developing AutoCAD, Civil 3D, or Plant 3D plugins, including scaffolding projects and working with their .NET APIs.
Why use it?
It records the required framework, SDK versions, environment variables, and project templates so plugin work follows the expected setup.

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/adn-devtech/acad-api-skill/acad-plugin
Clone the repo
git clone --depth 1 https://github.com/ADN-DevTech/acad-api-skill

Made for: Cursor.

Per session 355 This file is loaded in full into every session.
When invoked 355 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 $0.00355 $0.00355
Opus 5 $0.00178 $0.00178
Sonnet 5 $0.00071 $0.00071
Haiku 4.5 $0.00036 $0.00036

Measured yesterday against content hash 7b656b131b7a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

acad-plugin 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/acad-plugin.mdc · 28 lines

What it actually says

AutoCAD .NET Plugin Development

Refer to CLAUDE.md in this repository root for the full skill set.

Quick Reference

  • Framework: net10.0-windows, platform win-x64
  • AutoCAD.NET: 26.0.0 | Civil3D.NET: 13.9.628 | Plant 3D: local SDK (no NuGet)
  • Scaffold: dotnet new acad (AutoCAD/Plant base), dotnet new civil (Civil 3D)
  • Plant SDK path: PLANT_SDK env var / MSBuild property — must be set by user
  • AutoCAD install: ACAD_HOME env var — prompt user if not set
  • Remove the skill pack: see CLAUDE.mdUninstalling the skill pack (templates + which folders to delete)

Skills in this repo

  • skills/scaffold.md — step-by-step project creation
  • skills/autocad-api.md — base AutoCAD .NET patterns
  • skills/civil3d-api.md — Civil 3D API patterns
  • skills/plant3d-api.md — Plant 3D world map + full API patterns
  • skills/code-sleuth.md — finding SDK samples and API references
  • skills/learnings.md — append-only log of new discoveries (do NOT edit main skill files directly)
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 · 28 lines · 355 tokens per session scan A 7b656b131b7a

Subscribe to this mod's changes

acad-plugin is a cursor rule published in the GitHub repository ADN-DevTech/acad-api-skill (12 stars, last pushed 3mo ago), licensed MIT. It adds 355 tokens to every session, about $0.0018 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 2026-08-30.