diagnostics-development

To create Biome diagnostics, implement the `Diagnostic` trait or use the `#[derive(Diagnostic)]` macro. This defines precise error messages and actionable advice for your lint rules, ensuring users understand reported code issues.

Biome diagnostics support several advice types, including Log, CodeFrame, Diff, and Command. These allow you to add helpful context, suggest fixes, and provide detailed explanations directly within the diagnostic output.

The `markup!` macro enables rich text formatting in Biome diagnostics. You use it to apply emphasis, format inline code snippets, and add hyperlinks within error messages, creating a more readable and actionable output for developers.

The best way to provide actionable fixes in Biome is by utilizing advice types like Diff and Command. These mechanisms attach suggested code changes and helpful context directly to the diagnostic, allowing users to quickly resolve reported issues.

Use the `#[derive(Diagnostic)]` macro for standard lint rule errors to reduce boilerplate, and implement the `Diagnostic` trait manually when you need custom diagnostic logic or highly specialized advice types beyond the macro's defaults.