Skills

Skill 116 of 200

Csharp Async

Get best practices for C# async programming

1 minute · 219 words · 7 sections

Install

$ npx skills add github/awesome-copilot --skill csharp-async

$ npx skills add github/awesome-copilot

» /plugin marketplace add github/awesome-copilot

The first command installs just this skill, by the name in its SKILL.md; the second installs the whole repository.

C# Async Programming Best Practices

Your goal is to help me follow best practices for asynchronous programming in C#.

Naming Conventions

Use the ‘Async’ suffix for all async methods
Match method names with their synchronous counterparts when applicable (e.g., GetDataAsync() for GetData())

Return Types

Return Task<T> when the method returns a value
Return Task when the method doesn’t return a value
Consider ValueTask<T> for high-performance scenarios to reduce allocations
Avoid returning void for async methods except for event handlers

Exception Handling

Use try/catch blocks around await expressions
Avoid swallowing exceptions in async methods
Use ConfigureAwait(false) when appropriate to prevent deadlocks in library code
Propagate exceptions with Task.FromException() instead of throwing in async Task returning methods

Performance

Use Task.WhenAll() for parallel execution of multiple tasks
Use Task.WhenAny() for implementing timeouts or taking the first completed task
Avoid unnecessary async/await when simply passing through task results
Consider cancellation tokens for long-running operations

Common Pitfalls

Never use .Wait(), .Result, or .GetAwaiter().GetResult() in async code
Avoid mixing blocking and async code
Don’t create async void methods (except for event handlers)
Always await Task-returning methods

Implementation Patterns

Implement the async command pattern for long-running operations
Use async streams (IAsyncEnumerable) for processing sequences asynchronously
Consider the task-based asynchronous pattern (TAP) for public APIs

When reviewing my C# code, identify these issues and suggest improvements that follow these best practices.

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How this issue was made

Source

github.com/github/awesome-copilot, branch main, last pushed 24 September 2026.

Licence

MIT — the text of every skill is reproduced unmodified, frontmatter included, under the upstream licence.

Discovery

200 skills found by walking the repository tree for SKILL.md, not by matching a directory convention. 2 distinct layouts observed: .github/skills/*/SKILL.md, skills/*/SKILL.md.

Authorship

3 of 200 skills are installed into the repository rather than published from it. They are shelved in the closing “Credited skills” part and remain the work of their own authors. A skill counts as credited when its only copy lives under one agent’s dot directory; visible directories, per-agent mirror sets, and skills installable from this repository on skills.sh all count as published.

Issue colours

Resolved from a curated brand profile — hue 295°, chroma 0.190. Two accent tones are generated per issue and each is proven against its own ground before it ships: a single accent that passes AA on both light and dark paper is arithmetically impossible.

Heading repairs

1 repair applied to this skill so the document has one h1 and no skipped levels:

Shifted “7 headings” from h1 to h2 so the skill title is the only h1.

Spec compliance

Every skill satisfies the Agent Skills specification’s frontmatter rules.

Images

Images inside a skill come from the upstream repository. Where the author gave no alternative text we mark the image decorative rather than inventing a description — a plausible caption we made up is worse than none for the reader who depends on it.

Marketplace

A plugin manifest is published at .github/plugin/marketplace.json by GitHub, declaring 162 plugins. It is read for editorial metadata only — never as the skill index, which is always the repository tree.

Signal

Install counts come from skills.sh. They measure downloads, not quality, and an unranked repository is not an unread one.

Agent surfaces

The whole issue is available as one markdown document at /github/awesome-copilot.md, and each skill at its own .md URL.

Publication

Set by Skills Docs from the source repository. Body text is Literata at the reader’s chosen size and measure; code is Geist Mono. Nothing on this page was written by us except this paragraph.

C# Async Programming Best Practices

Your goal is to help me follow best practices for asynchronous programming in C#.

Naming Conventions

Use the ‘Async’ suffix for all async methods
Match method names with their synchronous counterparts when applicable (e.g., GetDataAsync() for GetData())

Return Types

Return Task<T> when the method returns a value
Return Task when the method doesn’t return a value
Consider ValueTask<T> for high-performance scenarios to reduce allocations
Avoid returning void for async methods except for event handlers

Exception Handling

Use try/catch blocks around await expressions
Avoid swallowing exceptions in async methods
Use ConfigureAwait(false) when appropriate to prevent deadlocks in library code
Propagate exceptions with Task.FromException() instead of throwing in async Task returning methods

Performance

Use Task.WhenAll() for parallel execution of multiple tasks
Use Task.WhenAny() for implementing timeouts or taking the first completed task
Avoid unnecessary async/await when simply passing through task results
Consider cancellation tokens for long-running operations

Common Pitfalls

Never use .Wait(), .Result, or .GetAwaiter().GetResult() in async code
Avoid mixing blocking and async code
Don’t create async void methods (except for event handlers)
Always await Task-returning methods

Implementation Patterns

Implement the async command pattern for long-running operations
Use async streams (IAsyncEnumerable) for processing sequences asynchronously
Consider the task-based asynchronous pattern (TAP) for public APIs

When reviewing my C# code, identify these issues and suggest improvements that follow these best practices.