docs: update CONTRIBUTING.md (#214)

CONTRIBUTING.md

@@ -4,18 +4,50 @@ Please note that this project is released with a
 [Contributor Code of Conduct](CODE-OF-CONDUCT.md). By participating in this
 project you agree to abide by its terms.
 
----
+## Pull Requests
 
 Ensure your pull request adheres to the following guidelines:
 
 - Use the [Conventional Commits specification](https://www.conventionalcommits.org/en/v1.0.0/) (`<type>[optional scope]: <description>`)
-- List items should be sorted alphabetically
+- **Alphabetical Sorting**: Items in `README.md` must be sorted alphabetically. See [Sorting Rules](#sorting-rules).
+- **Generated Content**: Some files, like `CLIENTS.md` are automatically generated from files. You should only edit the original source files from which they're generated from. See [Generated Content](#generated-content).
 - Search previous suggestions before making a new one, as yours may be a duplicate
 - New categories, or improvements to the existing categorization are welcome
 - Keep descriptions short and simple, but descriptive and non-promotional
 
 Thank you for your suggestions!
 
+## Sorting Rules
+
+Certain lists within this repository should be kept **alphabetically sorted**, according to a canonical version of each item. 
+The rules for deriving this canonical version (used for sorting) are as follows:
+
+1. **Square Brackets**:  
+   - If the line contains text in square brackets (e.g., `- [My Item]`), only that bracketed text is used to determine the item's position.
+   - If there are no square brackets, the entire line (minus the leading "`- `" if present) is used.
+2. **Removing Characters**:  
+   - From that resulting text, remove the following characters for sorting:
+       ```
+       [ -_().`',:!?]
+       ```
+
+If two items end up with the same canonical text, their **original order** is preserved. 
+
+> [!NOTE]
+> A bot will automatically check your PR for correct order.  
+>  - You can manually fix sorting or ask a maintainer to run `/sort-check -fix` (if needed).
+
+## Generated Content
+
+Some files in this repository are automatically generated from other source files. For example, `CLIENTS.md` is generated from `assets/clients/clients.yaml`.  
+- **Do not edit these generated files directly.** Instead, edit the original source files from which they’re generated.  
+- Each generated file clearly indicates that it is automatically generated.
+- Once you push your changes to the source file, the project’s checks will automatically regenerate the corresponding output file.  
+
+> [!NOTE]
+> For pull requests, a preview of the updated generated files will appear in the **Checks** tab of the pull request.
+> ![image](https://github.com/user-attachments/assets/5ca13a18-f68d-4dc5-b91b-caa9015132d0)
+
 
 ## Updating your PR