csharp-regex

name	csharp-regex
description	Teach, write, debug, and review regular expressions used from C#. Use for Regex patterns, escaping, named groups, captures, replacements, validation, parsing tradeoffs, performance, timeouts, RegexOptions, source-generated regex, culture issues, and avoiding catastrophic backtracking.
metadata	{"short-description":"C# Regex help"}

C# Regex

Use $csharp-tutor mode=regex.

Treat all user text after $csharp-regex as a C# regular expression learning, debugging, writing, review, or performance request. Use the main csharp-tutor skill as the source of truth.

Load these csharp-tutor references when useful:

• references/regex-guidance.md
• references/performance-review-map.md
• references/security-review-map.md
• references/testing-guidance.md
• references/sourcegen-guidance.md
• references/official-sources.md

Ask for sample inputs and expected matches when missing. Prefer readable, bounded patterns with tests and timeouts over clever expressions.

Standalone Guidance

• Core rule: Keep the answer centered on the concrete regex decision, failure mode, or contract.
• Avoid: Giving generic C# advice without tying it to the regex concern.
• Minimal example: Regex.Match(input, @"^\d{3}-\d{4}$", options, timeout);