Update AGENTS.md with naming and consistency guidelines

Clarified naming conventions and noun number consistency guidelines.

Author: bact

AGENTS.md

@@ -42,14 +42,17 @@
 - [ ] Do not use os.path.join();
       always use pythainlp.tools.safe_path_join() instead,
       to prevent path traversal vulnerabilities (CWE-22).
-- [ ] Naming conventions: Follows PEP 8.
+- [ ] Naming conventions: Follows PEP 8. 
       Align new modules, classes, public APIs, and environment
-      variables with NLTK conventions as the primary standard.
+      variables with NLTK conventions as the primary standard,
+      provided they suit the component's behavior.
       If NLTK offers no clear precedent, defer to established NLP
       frameworks in the following order of preference:
-      spaCy, CoreNLP/Stanza, LangPipe, and Hugging Face,
-      Ensure the chosen name accurately reflects the nature and
-      behavior of the component.
+      spaCy, CoreNLP/Stanza, LangPipe, and Hugging Face.
+- [ ] Noun number consistency: Maintain strict intentionality
+      regarding singular vs. plural forms. Use singular names for
+      classes representing a single entity and reserve plural
+      names only for collections, utility modules, or clear aggregates.
 
 ## Project contribution guidelines