docs: readme

README.md

@@ -7,6 +7,53 @@
 
 Comment-as-command for one-off codemod with ESLint.
 
+## Introduction
+
+**ESLint Plugin Command** is a special kind of ESLint plugin, that by default, **does nothing**. Instead of checking for code quality, it serves as a micro-codemod tool triggers by special comments on-demand, resuse the infrastructure of ESLint.
+
+For example, one of the built-in commands, `/// to-function` allows you to convert a single arrow function expression to a function declaration.
+
+<!-- eslint-skip -->
+
+```ts
+/// to-function
+const foo = async <T>(msg: T): void => {
+  console.log(msg)
+}
+```
+
+Will be transformed to this when you hit save with your editor or run `eslint . --fix`. After executing the command, the comment will also be removed along with the transformation:
+
+```ts
+async function foo<T>(msg: T): void {
+  console.log(msg)
+}
+```
+
+One more example that `/// to-promis-all` converts a sequence of `await` expressions to `await Promise.all()`:
+
+<!-- eslint-skip -->
+
+```ts
+/// to-promise-all
+const foo = await bar().then
+const { get } = await import('lodash-es')
+```
+
+Will be transformed to:
+
+```ts
+const [
+  foo,
+  { get },
+] = await Promise.all([
+  bar(),
+  import('lodash-es'),
+] as const)
+```
+
+Refer to the [documentation](https://eslint-plugin-command.antfu.me/) for more details.
+
 ## Sponsors
 
 <p align="center">