Add Extension Assets

Adds extension assets to a campaign — or to ONE AD GROUP when ad_group_id is given. AD GROUP LEVEL: pass ad_group_id (campaign_id may then be left empty; it is resolved from the ad group) and every asset created or linked here is attached as an AdGroupAsset to that ad group only. Google serves ad-group assets INSTEAD of the campaign's assets of the same type for that ad group's ads, so a branch ad group can show its own phone number, WhatsApp chat, sitelinks and callouts while the rest of the campaign keeps the campaign-level ones. Assets created for one ad group are reused on a second ad group with link_asset_ids and the other ad_group_id (no duplicates are created). callouts: a list of short highlights. sitelinks: lines in 'text|url' or 'text|url|description1|description2' format. phone_number (+phone_country) adds a call extension. snippet_header + snippet_values add a structured snippet (the header comes from Google's fixed list, such as Services or Brands). whatsapp_number (+whatsapp_country, whatsapp_greeting, whatsapp_cta, whatsapp_cta_text) adds a MESSAGE extension (BUSINESS_MESSAGE) that opens a WhatsApp chat; Google requires all five: greeting is the pre-filled first message, whatsapp_cta is one of APPLY_NOW, BOOK_NOW, CONTACT_US, GET_INFO, GET_OFFER, GET_QUOTE, GET_STARTED, LEARN_MORE, and whatsapp_cta_text is the button description (max 30 chars). Only WhatsApp is supported (Facebook Messenger and Zalo need provider data Google does not expose here). prices: PRICE extensions, one line per offering in 'Header|Description|<amount> <currency>|https://url' format (optional extra '|unit:PER_MONTH'); 3 to 8 offerings are required, headers must be unique and max 25 chars, descriptions max 25 chars. price_type groups them (SERVICES, BRANDS, PRODUCT_CATEGORIES, NEIGHBORHOODS, EVENTS, LOCATIONS, PRODUCT_TIERS, SERVICE_CATEGORIES, SERVICE_TIERS), price_qualifier is optional (FROM, UP_TO, AVERAGE) and price_language must be one of de, en, es, fr, it, ja, nl, pl, pt_BR, ru, sv. Measured against the live API: Google does NOT support Turkish (tr) or the Turkish lira (TRY) for price extensions, so a TRY account cannot use them; the tool says so. promotions: PROMOTION extensions in 'Target text|discount|https://url' format; discount is '%<n>' (percent) or '<amount> <currency>'; optional extra '|key:value' segments: code:<code>, min:<amount> (minimum order amount, mutually exclusive with code), start:YYYY-MM-DD, end:YYYY-MM-DD, occasion:<OCCASION>, lang:<code>, modifier:UP_TO. link_asset_ids: comma-separated asset IDs ALREADY in the account's asset library (from list_assets): links them to the campaign INSTEAD of creating duplicates; the field type is derived from the asset's own type (PROMOTION, SITELINK, CALLOUT, CALL, STRUCTURED_SNIPPET, PRICE, MOBILE_APP, HOTEL_CALLOUT, LEAD_FORM, IMAGE). IMAGE assets (from upload_image_asset) are linked as the Search IMAGE EXTENSION (field type AD_IMAGE) — Google requires at least 300x300 px and accepts 1.91:1 and 1:1 crops. At least one extension type is required. confirm=false → dry-run. To VIEW or REMOVE existing extensions, use list_extension_assets and remove_extension_assets. LOCATION (business address, map pin, "Get directions") is NOT an extension type here: location assets are generated automatically from the Google Business Profile link and serve account-wide — inspect or pin them with add_location_assets.