Csharp Style

C# Style

Naming and layout

• Give every identifier its full domain meaning; never use a single-character or abbreviated name.
• Suffix a method returning Task or Task with Async.
• Use file-scoped namespaces.
• Order members: private fields, constructor, public properties, public methods, private methods.

Language features

• Use the newest language feature that makes intent clearer without hiding control flow or allocation.
• Use is null / is not null for null checks; never the empty property pattern is { } as a null check.
• Combine predicates over one expression with and/or/not patterns; parenthesize when precedence is not obvious.
• Use collection expressions ([…]) for clear collection literals.

Nullability and annotations

• Enable nullable reference types; keep public and internal contracts null-safe.
• Express real, IDE- or compiler-visible contracts with annotations from the JetBrains and System.Diagnostics.CodeAnalysis sets — both are large, so reach for whichever fits rather than a fixed few.
• Apply [Pure] to side-effect-free members and [NotNullWhen] to Try-style methods with an out result as a habit; add the rest ([PublicAPI], [MustUseReturnValue], [MemberNotNull], [DoesNotReturnIf], [StringSyntax], …) wherever their exact condition holds.

Asynchronous code

• Use Task/Task; reserve async void for a framework-required event handler.
• Flow CancellationToken through I/O, broker, storage, and long-running work.
• Never block an async flow with .Result, .Wait(), or synchronous sleeps.

Data contracts

• Use record for DTOs, message contracts, and configuration-style data.
• Use init properties unless a caller must mutate after construction.
• Keep a contract stable and explicit once another process or service depends on it.

Error handling

• Validate untrusted input at a public boundary.
• Prefer a semantic exception over a generic Exception.
• Catch only at a boundary that can add context, clean up, or choose recovery — never a broad catch with no recovery.

Performance

• Measure a hot path before micro-optimizing.
• Remove repeated parsing, allocation, and intermediate collections before reaching for a lower-level primitive.
• Use Span/ReadOnlySpan only when it materially removes copying without obscuring ownership.
• Keep expensive work out of constructors and deserialization paths; dispose owned streams and pooled resources in their owner scope.

Review

• [ ] Identifiers carry full domain meaning; async methods end in Async.
• [ ] Nullability is explicit and annotations match real contracts.
• [ ] Async paths flow CancellationToken and never block.
• [ ] Shared data contracts are immutable record types.
• [ ] Exceptions are semantic and caught only where recovery or context is added.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Nice3point
• Source: Nice3point/revit-skills
• License: MIT

Install and usage instructions live in the source repository linked above.