Terminal.Gui/CLAUDE.md

CLAUDE.md

Guidance for AI agents working with Terminal.Gui. For humans, see CONTRIBUTING.md. See also: llms.txt for machine-readable context.

Quick Reference: What Are You Doing?

Your Task	Go Here
"Build me an app that..."	.claude/tasks/build-app.md
"Add a feature to Terminal.Gui..."	Continue below (Contributor Guide)
"Fix a bug in Terminal.Gui..."	Continue below (Contributor Guide)

App Builder Quick Start

dotnet new install Terminal.Gui.Templates@2.0.0-alpha.*
dotnet new tui-simple -n myapp
cd myapp
dotnet run

See .claude/tasks/build-app.md for complete app development guide. See .claude/cookbook/common-patterns.md for UI recipes.

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Contributor Guide

The rest of this file is for contributors modifying Terminal.Gui itself.

Before Every File Edit

READ .claude/REFRESH.md first. It contains a quick checklist to prevent common mistakes.

Detailed Rules

See .claude/rules/ for detailed guidance:

• type-declarations.md - No var except built-in types
• target-typed-new.md - Use new () not new TypeName()
• terminology.md - SubView/SuperView, never "child/parent"
• event-patterns.md - Lambdas, closures, handlers
• collection-expressions.md - Use [...] syntax
• cwp-pattern.md - Cancellable Workflow Pattern

Task-Specific Guides

See .claude/tasks/ for task checklists:

• build-app.md - Building applications with Terminal.Gui

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Project Overview

Terminal.Gui - Cross-platform .NET console UI toolkit

• Language: C# (net8.0)
• Branch: v2_develop
• Version: v2 (Alpha)

Build & Test

dotnet restore
dotnet build --no-restore
dotnet test Tests/UnitTestsParallelizable --no-build
dotnet test Tests/UnitTests --no-build

Key Concepts

Concept	Documentation
Application Lifecycle	docfx/docs/application.md
View Hierarchy	docfx/docs/View.md
Layout (Pos/Dim)	docfx/docs/layout.md
CWP Events	docfx/docs/cancellable-work-pattern.md
Terminology	docfx/docs/lexicon.md

Critical Rules (Summary)

1. No var except: int, string, bool, double, float, decimal, char, byte
2. Use new () not new TypeName()
3. Use [...] not new () { ... } for collections
4. SubView/SuperView for containment (Parent/Child only for non-containment refs)
5. Unused lambda params - use _: (_, _) => { }

Testing

• Prefer UnitTestsParallelizable over UnitTests
• Add comment: // Claude - Opus 4.5
• Never decrease coverage
• Avoid Application.Init in tests

Repository Structure

/Terminal.Gui/     - Core library
/Tests/            - Unit tests
/Examples/UICatalog/ - Demo app
/docfx/docs/       - Documentation
/.claude/          - AI agent guidance

What NOT to Do

• Don't use var for non-built-in types
• Don't use redundant type names with new
• Don't say "child/parent" for containment (use SubView/SuperView)
• Don't modify unrelated code
• Don't introduce new warnings