docs: Add more context for claude code.

Author: feanil

CLAUDE.md

@@ -3,6 +3,7 @@
 This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
 
 ## Build/Lint/Test Commands
+- Make sure to set the following so that test output is not too verbose: `export PYTEST_ADDOPTS="--disable-warnings --no-header --tb=short"`
 - Backend testing: `cd backend && pytest` or `cd backend && make test`
 - Run a single test: `cd backend && pytest tests/test_models.py::test_placeholder`
 - Quality checks: `cd backend && make quality`
@@ -19,3 +20,8 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 - Frontend uses React and follows standard JSX conventions
 
 Always run `make quality` and fix issues before creating a PR to ensure consistent code style.
+
+## API Development Guidelines
+- Handle permission checking in viewsets rather than serializers to maintain separation of concerns
+- Use `perform_create()` and `perform_update()` in viewsets for business logic and permission validation
+- Test API endpoints for both regular user and admin/staff scenarios when permissions are involved