Meta campaign performance

Campaign-level results for a window, next to the same-length window before it, with the KPI each campaign's objective is actually judged on: purchases and purchase ROAS for sales, leads and cost per lead for lead generation, link clicks and CPC for traffic, reach and CPM for awareness, engagements for engagement, installs for app promotion. Use when: the user asks how Meta is doing, which campaigns are worth more budget, or what changed week over week. 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 to inspect settings (meta_list_campaigns) or to find waste inside an ad set (meta_analyze_wasted_spend). Returns "not applicable" rather than a blank or a zero for ROAS on objectives that record no revenue — never present a missing ROAS as a bad ROAS. If the user's date wording is vague ("recently", "lately"), ask which window they mean instead of picking one.