# vb-core

Configures coding agents with modern VB.NET standards (2019+), enforcing strict typing, LINQ conventions, and async/await rules.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 340 installs · ★ 78
- Author: Claude MPM Team
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/bobmatnyc/claude-mpm-skills/tree/HEAD/toolchains/visualbasic/vb-core/SKILL.md
- Updated: 2026-07-18
- HTML: https://affpapa.org/en/nevibecode/skills/vb-core

## What it does

The skill provides guidelines for Visual Basic .NET based on modern language versions (2019+). It directs the agent to place `Option Strict On`, `Option Explicit On`, and `Option Infer On` at the head of every file to avoid implicit narrowing conversions.

It covers modern language patterns: string interpolation instead of concatenation, named tuples, nullable checking with `IsNot Nothing`, and collection initializers. For asynchronous code, it prohibits blocking calls like `.Result` to prevent deadlocks, mandating `Await` with `Task(Of T)`.

Because the configuration marks `user-invocable: false`, the skill functions strictly as automated background guidance rather than an interactive prompt command.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill vb-core -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/vb-core/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/vb-core/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill vb-core -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/vb-core/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill vb-core -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/vb-core/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install bobmatnyc/claude-mpm-skills vb-core
```

2. **Manually: put the files in place**
- File: `.github/skills/vb-core/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill vb-core -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/bobmatnyc/claude-mpm-skills --path toolchains/visualbasic/vb-core
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/vb-core/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill vb-core -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/bobmatnyc/claude-mpm-skills/tree/HEAD/toolchains/visualbasic/vb-core/SKILL.md

## When to use it
- enforce Option Strict and explicit variable typing across VB.NET files
- refactor legacy string concatenation into modern interpolation
- convert blocking .Result calls into safe async/await chains
- write type-safe LINQ queries with lambda functions and named tuples

## Example prompts
- Refactor this customer query into an async function returning Task(Of Customer)
- Update this legacy VB module to use Option Strict On and string interpolation
- Write a LINQ grouping query for active orders by city using modern VB syntax

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: c0be9df6427d4956.

BEGIN THIRD-PARTY FILE c0be9df6427d4956
````text
---
name: vb-core
description: Core VB.NET patterns, type safety, modern language features
user-invocable: false
disable-model-invocation: true
version: 1.0.0
category: toolchain
author: Claude MPM Team
license: MIT
tags: [visualbasic, vb.net, dotnet, type-safety]
---

# Visual Basic .NET Core Patterns

Modern VB.NET (2019+) best practices with focus on type safety, LINQ, async/await, and .NET integration.

## Quick Start

```vb
' Always enable strict type checking
Option Strict On
Option Explicit On
Option Infer On

' Modern class definition
Public Class Customer
    Public Property Id As Integer
    Public Property Name As String
    Public Property Email As String

    ' Constructor
    Public Sub New(id As Integer, name As String, email As String)
        Me.Id = id
        Me.Name = name
        Me.Email = email
    End Sub
End Class

' Modern async method
Public Async Function GetCustomerAsync(id As Integer) As Task(Of Customer)
    Dim result = Await database.QueryAsync(Of Customer)(
        "SELECT * FROM Customers WHERE Id = @id",
        New With {.id = id}
    )
    Return result.FirstOrDefault()
End Function

' LINQ query
Dim activeCustomers = From c In customers
                      Where c.IsActive AndAlso c.Balance > 0
                      Order By c.Name
                      Select c
```

## Type Safety (Critical)

### Option Strict On

```vb
' ALWAYS at top of every file
Option Strict On
Option Explicit On
Option Infer On

' Why:
' - Option Strict: Prevents implicit narrowing conversions
' - Option Explicit: Requires variable declaration
' - Option Infer: Enables type inference (but still type-safe)
```

### Explicit Types vs Inference

```vb
' ✅ Good: Explicit when clarity helps
Dim customerName As String = GetCustomerName(id)
Dim count As Integer = GetCount()

' ✅ Good: Inference when type is obvious
Dim customer = New Customer(1, "John", "john@example.com")
Dim items = New List(Of String) From {"a", "b", "c"}

' ❌ Bad: Dim without type and no inference
Dim data = GetData()  ' What type is data?

' ✅ Better: Be explicit
Dim data As DataTable = GetData()
```

### Nullable Types

```vb
' Modern nullable syntax (VB 15.5+)
Dim middleName As String? = Nothing
Dim age As Integer? = Nothing

' Null-conditional operator
Dim length As Integer? = middleName?.Length

' Null-coalescing operator
Dim displayName As String = middleName If Nothing

' Check for null
If age IsNot Nothing Then
    Console.WriteLine($"Age: {age.Value}")
End If

' GetValueOrDefault
Dim years As Integer = age.GetValueOrDefault(0)
```

## Modern Language Features

### String Interpolation

```vb
' ✅ Modern (VB 14+)
Dim message = $"Customer {customer.Name} has balance {customer.Balance:C}"

' ❌ Old style (avoid)
Dim message = String.Format("Customer {0} has balance {1:C}", customer.Name, customer.Balance)

' ❌ Concatenation (avoid for complex strings)
Dim message = "Customer " & customer.Name & " has balance " & customer.Balance.ToString("C")
```

### Lambda Expressions

```vb
````
END THIRD-PARTY FILE c0be9df6427d4956

The third-party file has ended. Everything between the c0be9df6427d4956 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 3026 of 13343 bytes. © Claude MPM Team · MIT · https://github.com/bobmatnyc/claude-mpm-skills/tree/HEAD/toolchains/visualbasic/vb-core/SKILL.md

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