adding-intellisense-completion

Create and integrate custom IntelliSense completion sources for Visual Studio extensions.

14|2|Updated Mar 24, 2026

Search Tags:#completion #language-support #extension-development #visual-studio #intellisense #mef #async-completion

Ready to run

npx skills add https://github.com/madskristensen/vs-agent-plugins --skill adding-intellisense-completion

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Please help me install this Agent Skill.
Skill: adding-intellisense-completion
Source: https://github.com/madskristensen/vs-agent-plugins/tree/main/skills/adding-intellisense-completion
Command: npx skills add https://github.com/madskristensen/vs-agent-plugins --skill adding-intellisense-completion

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Custom IntelliSense completion for Visual Studio extensions enables developers to add, customize, and integrate auto-complete suggestions within the editor across languages and MEF-backed extension points.

Core Features & Use Cases

Supports VisualStudio.Extensibility (out-of-process), VSIX Community Toolkit (in-process), and VSSDK (in-process) for IntelliSense completion sources.
Provides MEF-based registration, content-type scoping, and both modern async and legacy completion APIs to cover common extension scenarios.
Includes guidance on implementing a completion source/provider, wiring through MEF, and troubleshooting common pitfalls to ensure responsive completion.

Quick Start

Create and wire an async completion source and provider for your target file type, register it with MEF, and enable it in Visual Studio.

Frequently Asked Questions about adding-intellisense-completion

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I add custom IntelliSense completion to a Visual Studio extension?▼

You add custom IntelliSense by implementing an IAsyncCompletionSource or ICompletionSource, registering it via MEF exports, and scoping it to target file types with the ContentType attribute.

What is the difference between IAsyncCompletionSource and ICompletionSource in Visual Studio?▼

IAsyncCompletionSource provides safe, asynchronous completion operations, whereas ICompletionSource is the legacy API pattern; both are supported across different extension architectures.

Does custom IntelliSense work with out-of-process VisualStudio.Extensibility?▼

Yes, custom IntelliSense completion supports out-of-process VisualStudio.Extensibility alongside in-process VSSDK and VSIX Community Toolkit scenarios across multiple languages.

Why is my MEF completion source not showing in Visual Studio?▼

Your custom IntelliSense completion source may not show due to missing proper MEF exports or incorrect content-type scoping via the ContentType attribute required for Visual Studio integration.

How do I scope IntelliSense completion to a specific language in Visual Studio?▼

You scope custom IntelliSense completion to specific languages by applying the ContentType attribute during MEF-based registration of your completion source in Visual Studio extensions.