Csharp Docs

C# Documentation Best Practices

• Public members should be documented with XML comments.
• It is encouraged to document internal members as well, especially if they are complex or not self-explanatory.
• Private methods that contain non-obvious or complex logic (e.g. pagination, parsing, filtering, error handling) must have an XML <summary> comment.
• Private DTO and mapping records (used for serialisation or API response mapping) should have a one-line <summary> describing their role — for example, which API endpoint they represent or what they serialise.
• Use inline // comments within method bodies for non-obvious logic: parsing decisions, API quirks, filtering rationale, or any code where the intent is not immediately clear from the identifier names alone.

Guidance for all APIs

• Use <summary> to provide a brief, one sentence, description of what the type or member does. Start the summary with a present-tense, third-person verb.
• Use <remarks> for additional information, which can include implementation details, usage notes, or any other relevant context.
• Use <see langword> for language-specific keywords like null, true, false, int, bool, etc.
• Use <c> for inline code snippets.
• Use <example> for usage examples on how to use the member.
  • Use <code> for code blocks. <code> tags should be placed within an <example> tag. Add the language of the code example using the language attribute, for example, <code language="csharp">.
• Use <see cref> to reference other types or members inline (in a sentence).
• Use <seealso> for standalone (not in a sentence) references to other types or members in the "See also" section of the online docs.
• Use <inheritdoc/> to inherit documentation from base classes or interfaces.
  • Unless there is major behaviour change, in which case you should document the differences.
  • If an implementation applies filtering, pagination, mapping transformations, or any logic not implied by the interface contract, add a <remarks> block alongside <inheritdoc/> to describe it. Do not rely on <inheritdoc/> alone when the implementation diverges from a literal reading of the interface.

Methods

• Use <param> to describe method parameters.
  • The description should be a noun phrase that doesn't specify the data type.
  • Begin with an introductory article.
  • If the parameter is a flag enum, start the description with "A bitwise combination of the enumeration values that specifies...".
  • If the parameter is a non-flag enum, start the description with "One of the enumeration values that specifies...".
  • If the parameter is a Boolean, the wording should be of the form "<see langword="true" /> to ...; otherwise, <see langword="false" />.".
  • If the parameter is an "out" parameter, the wording should be of the form "When this method returns, contains .... This parameter is treated as uninitialized.".
• Use <paramref> to reference parameter names in documentation.
• Use <typeparam> to describe type parameters in generic types or methods.
• Use <typeparamref> to reference type parameters in documentation.
• Use <returns> to describe what the method returns.
  • The description should be a noun phrase that doesn't specify the data type.
  • Begin with an introductory article.
  • If the return type is Boolean, the wording should be of the form "<see langword="true" /> if ...; otherwise, <see langword="false" />.".

Constructors

• The summary wording should be "Initializes a new instance of the class [or struct].".

Properties

• The <summary> should start with:
  • "Gets or sets..." for a read-write property.
  • "Gets..." for a read-only property.
  • "Gets [or sets] a value that indicates whether..." for properties that return a Boolean value.
• Use <value> to describe the value of the property.
  • The description should be a noun phrase that doesn't specify the data type.
  • If the property has a default value, add it in a separate sentence, for example, "The default is <see langword="false" />".
  • If the value type is Boolean, the wording should be of the form "<see langword="true" /> if ...; otherwise, <see langword="false" />. The default is ...".

Exceptions

• Use <exception cref> to document exceptions thrown by constructors, properties, indexers, methods, operators, and events.
• Document all exceptions thrown directly by the member.
• For exceptions thrown by nested members, document only the exceptions users are most likely to encounter.
• The description of the exception describes the condition under which it's thrown.
  • Omit "Thrown if ..." or "If ..." at the beginning of the sentence. Just state the condition directly, for example "An error occurred when accessing a Message Queuing API."