diff --git a/cmd/server/tests/test_helpers.go b/cmd/server/tests/test_helpers.go
index 4f41ff3..4c86779 100644
--- a/cmd/server/tests/test_helpers.go
+++ b/cmd/server/tests/test_helpers.go
@@ -529,6 +529,16 @@ func setupTestServer(t *testing.T) *TestServerSetup {
 		}
 	}
 
+	// Delete test libraries (names containing "test" - case insensitive)
+	// This cleans up libraries created by tests while preserving user-created libraries
+	// NOTE: Do not use "test" in library names if you want to keep them!
+	allLibs, _ := queries.ListLibraries(ctx)
+	for _, lib := range allLibs {
+		if strings.Contains(strings.ToLower(lib.Name), "test") {
+			queries.DeleteLibrary(ctx, lib.ID)
+		}
+	}
+
 	// Create fresh admin test user
 	passwordHash := "$2a$10$JjAtK7PPa1WexQC3AUGe8OXLeuseZ/haN1Mz7emMo6CfOvMiTVXWq"
 	adminUser, err := queries.CreateUser(ctx, database.CreateUserParams{
diff --git a/docs/contributing/development.md b/docs/contributing/development.md
index 2c4ca19..33113aa 100644
--- a/docs/contributing/development.md
+++ b/docs/contributing/development.md
@@ -279,6 +279,15 @@ Environment variables for testing:
 
 **⚠️ WARNING**: Never enable these in production!
 
+### Test Library Naming Convention
+
+Integration tests automatically clean up libraries with "test" in the name (case-insensitive).
+
+**⚠️ IMPORTANT**: Do not use "test" in library names if you want to keep them!
+- Libraries containing "test" (e.g., "My Test Library", "Test Library 1") will be deleted by test cleanup
+- Use names like "Development Library", "Staging Books", or "Personal" for libraries you want to keep
+- This ensures your manual test data persists between test runs
+
 ## 📝 Code Style Guidelines
 
 ### Go Code