Update README.md

tools/@aws-cdk/prlint/README.md

@@ -1,23 +1,50 @@
 # prlint
 
-A Github action that checks pull requests around PR titles, description and other metadata.
+This package includes a GitHub Action that does the following:
+- Checks pull requests around PR titles, description and other metadata.
+- Assesses whether or not the PR is ready for review and attaches the correct label to the PR.
 
-# Checks
+# Rules
 
-### Mandatory Changes
+The first part of the GitHub Action validates whether or not the pull request adheres
+(or has been exempted from) to the following rules:
 
-This check validates that the modified files in the PR follow these rules:
-
-1. `feat` requires a change to a `README.md`.
-2. `feat` requires a change to a unit test file and integration test files.
-3. `fix` requires a change to a unit test file and integration test files.
+1. `feat` requires a change to a `README.md` (exemption is the label `pr-linter/exempt-readme`).
+2. Both `feat` and `fix` PRs require a change to a unit test file and integration test files (exemption is the label `pr-linter/exempt-unit-test` or `pr-linter/exempt-integ-test`).
 4. `BREAKING CHANGE` section is formatted correctly, per the [conventional commits] spec.
 5. No breaking changes announced for stable modules.
+6. Title prefix and scope is formatted correctly.
+7. The PR is not opened from the main branch of the author's fork.
+8. Changes to the cli have been run through the test pipeline where cli integ tests are run (indicated by the label `pr-linter/cli-integ-tested`).
+9. No manual changes to `packages/aws-cdk-lib/region-info/build-tools/metadata.ts` file.
 
 > These rules are currently hard coded, in the future, we should consider using [danger.js](https://danger.systems/js/).
 
 [conventional commits]: https://www.conventionalcommits.org
 
+# Evaluation and Assigning Labels
+
+The GitHub Action also handles whether or not the PR is ready for review, and by whom.
+A PR is ready for review when:
+
+1. It is not a draft
+2. It does not have any merge conflicts
+3. The PR linter is not failing OR the user has requested an exemption (`pr-linter/exemption-requested`)
+4. A maintainer has not requested changes
+5. A maintainer has not approved
+
+If the PR is ready for review, we also differentiate whether or not it is ready for a
+maintainer review (`pr/needs-maintainer-review`) or if we are soliciting help from our
+pool of trusted reviewers (`pr/needs-community-review`).
+
+A PR is prioritized for core team review when:
+
+1. It links to a p1 issue
+2. It links to a p2 issue and has an approved community review
+
+Based on the above rules, prlint will apply the correct label `pr/needs-maintainer-review` or `pr/needs-community-review`
+to the PR.
+
 # Installation
 
 ```console