Google Ads campaign performance with period-over-period change

Reports spend, impressions, clicks, CTR, conversions, conversion value, CPA and ROAS per campaign for a period, plus the change against the immediately preceding period of the same length. Use when: the user asks how campaigns performed, whether results improved, or what a campaign costs per conversion. Do not use it for a brief or a report to keep or forward: that is generate_report_now (monitoring router), which covers every connected account and saves a page. Do not use when: the user wants to know what exists rather than how it performed (google_list_campaigns), or wants search-query detail (google_analyze_search_terms). Pass either date_range (a preset) or start_date + end_date, never both. Periods are calendar days in the account's own timezone. Money is a decimal in the account currency. CPA is blank when there were no conversions and ROAS is blank when there was no spend — say so rather than printing zero. If you are unsure which account, campaign or period the user means, ask them — do not guess ids or dates.