> For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt.

# Compilation diagnostic rules

Build diagnostics complement static lint tools such as ESLint. They run against Rspack's build data and can use information such as the ModuleGraph, per-module metadata, and generated runtime code.

During the build process, if issues are discovered, they will be visible in the CLI and the final diagnostic summary webpage, as shown below:

![](https://assets.rspack.rs/others/assets/rsdoctor/rule-config-cli.png)
![](https://assets.rspack.rs/others/assets/rsdoctor/bundle-alerts.png)
## How to use

Currently, Rsdoctor provides **built-in rules** and **custom rules**.

### Built-in Rules

The existing diagnostic tool includes multiple rules, all of which are enabled by default. They are:

1. [\[E1001\] Duplicate Packages](/guide/rules/rules.md#e1001-duplicate-packages)
2. [\[E1002\] Cross Chunks Package](/guide/rules/rules.md#e1002-cross-chunks-package)
3. [\[E1003\] Loader Performance Optimization](/guide/rules/rules.md#e1003-loader-performance-optimization)
4. [\[E1004\] ECMA Version Check](/guide/rules/rules.md#e1004-ecma-version-check)
5. [\[E1005\] Default Import Check](/guide/rules/rules.md#e1005-default-import-check)

For specific details, refer to [Built-in Rules](/guide/rules/rules.md).

### Custom rules

Rsdoctor also collects analyzed data and allows users to integrate custom rules through the Linter API. For details on custom rules, refer to [Custom Rules](/guide/rules/rule-custom.md).