Document GitHub limitations

README.md

@@ -261,6 +261,17 @@ You can use following example configuration in `package.json`:
 Configuration of `uniqueOutputName`, `suiteNameTemplate`, `classNameTemplate`, `titleTemplate` is important for proper visualization of test results.
 </details>
 
+## GitHub limitations
+
+Unfortunately there are some known issues and limitations caused by GitHub API:
+
+- Test report (i.e. Check Run summary) is markdown text. No custom styling or HTML is possible.
+- Maximum report size is 65535 bytes. Input parameters `list-suites` and `list-tests` will be automatically adjusted if max size is exceeded.
+- Test report can't reference any additional files (e.g. screenshots). You can use `actions/upload-artifact@v2` to upload them and inspect manually.
+- Check Runs are created for specific commit SHA. it's not possible to specify under which workflow test report should belong if there are more
+  workflows running for same SHA. Thanks to this GitHub "feature" it's possible your test report will appear in unexpected place in GitHub UI.
+  For more information see [#67](https://github.com/dorny/test-reporter/issues/67).
+
 ## See also
 - [paths-filter](https://github.com/dorny/paths-filter) - Conditionally run actions based on files modified by PR, feature branch or pushed commits