acad-api-skill copilot-instructions.md

A development guide for building AutoCAD, Civil 3D, and Plant 3D plugins with .NET. These plugins extend Autodesk desktop or headless design tools.

In plain words
What is it for?
Use it when scaffolding a plugin, calling AutoCAD APIs, working with Civil 3D or Plant 3D, testing, plotting, or preparing deployment.
Why use it?
It helps agents use the correct SDK assemblies, target platform, project setup, and write-operation safeguards without packaging Autodesk files incorrectly.

Instructions file for GitHub Copilot

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

Made for: GitHub Copilot.

Per session 504 This file is loaded in full into every session.
When invoked 504 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 $0.00504 $0.00504
Opus 5 $0.00252 $0.00252
Sonnet 5 $0.00101 $0.00101
Haiku 4.5 $0.00050 $0.00050

Measured 2d ago against content hash e88f6fc29449, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

acad-api-skill copilot-instructions.md 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 2d 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.

.github/copilot-instructions.md · 28 lines

What it actually says

GitHub Copilot Instructions — AutoCAD .NET Plugin Development

This repository is an agentic skill set for building AutoCAD 2027 .NET plugins. See CLAUDE.md for full guidance.

Target stack

  • .NET 10 (net10.0-windows), <PlatformTarget>x64</PlatformTarget>
  • AutoCAD.NET 26.0.0 (desktop) or AutoCAD.NET.Core 26.0.0 + AutoCAD.NET.Model 26.0.0 (DA/headless)
  • Civil3D.NET 13.9.628 for Civil 3D toolset
  • Plant 3D: local SDK DLL references -- path in PLANT_SDK env var / MSBuild property

When generating plugin code

  1. Check skills/scaffold.md for project setup, testing, and deployment steps
  2. Check skills/autocad-api.md for assembly/DLL map, plotting, accoreconsole flags, and common gotchas
  3. Check skills/civil3d-api.md or skills/plant3d-api.md for product-specific patterns
  4. Check skills/code-sleuth.md for SDK sample locations before inventing API usage
  5. Never copy AutoCAD/Civil/Plant assemblies to output (ExcludeAssets="runtime" or Private=false)
  6. Use <PlatformTarget>x64</PlatformTarget> instead of <RuntimeIdentifier> (unless required for cross-platform native NuGet dependencies like Oracle).
  7. Wrap all write operations in DocumentLock
  8. All toolset API calls on main AutoCAD thread only
  9. For DA/headless: use AutoCAD.NET.Core + AutoCAD.NET.Model only (no AcMgd.dll)
  10. When discovering new gotchas or API behaviors not in the skill files, append to skills/learnings.md — never edit main skill files directly

Uninstalling the skill pack

See CLAUDE.md section Uninstalling the skill pack: run npx github:ADN-DevTech/acad-api-skill uninstall to unregister dotnet new templates, then delete the copied skills/ (and .cursor/, .github/, CLAUDE.md as applicable) from the project where install was run. The installer prints absolute paths after a successful install.

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. 2d ago First seen · 28 lines · 504 tokens per session scan A e88f6fc29449

Subscribe to this mod's changes

acad-api-skill copilot-instructions.md is an instructions file published in the GitHub repository ADN-DevTech/acad-api-skill (12 stars, last pushed 3mo ago), licensed MIT. It adds 504 tokens to every session, about $0.0025 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.

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