diagnose-underperformer

## Goal Pull the right report, walk a structured decision tree, and hand the user a ranked list of likely causes with the **specific next op to call** to fix it. No writes — diagnosis only. ## Inputs to confirm (batch) 1. Account name (substring) — required. 2. Target — campaign / ad set / ad name or ID — required. 3. Date range — default last 14 days; if the entity is < 14 days old, use its lifetime. 4. Comparison window (optional) — previous 14 days, for trend. 5. Primary KPI — conversions / ROAS / CPA / CPL — required if the entity has a conversion goal. ## Workflow 1. **Discover** ops. For Google Ads: `gads_select_accounts`, `gads_list_report_fields`, `gads_get_report`, `gads_get_account_history`. For Meta: `meta_ads_select_accounts`, `meta_ads_list_report_fields`, `meta_ads_get_report`, `meta_ads_get_account_history`, `meta_ads_get_adset_settings`, `meta_ads_get_campaign_settings`. 2. **Inspect** with `get_operation_inputs`. **Always call `*_list_report_fields` before `*_get_report`** — never guess metric/dimension names. 3. **Resolve account** with substring match. 4. **Pull the report** at the right granularity (campaign / ad set / ad). Required metrics: - Spend, impressions, clicks, CTR, CPC, conversions, conv rate, CPA / ROAS, frequency (Meta), search impression share + lost-to-budget + lost-to-rank (Google Search). 5. **Pull settings/history** to check for recent edits that could have triggered the dip: - Google: `gads_get_account_history` filtered to thi...