List which AI engines, platforms and markets each Vantage tool
accepts, and the per-call limits, so you can pick valid arguments before
spending any quota. Use this to answer 'does Vantage cover Gemini in
Italy' or 'what can I pass as engine or platform'.
Costs 0 quota units - a fixed list, it never touches the data provider.
Returns: {"live_answer": {"tools" (analyze_citation_coverage,
analyze_citation_structure, analyze_citation_structure_batch,
analyze_citation_gap), "engines" (the values for `engine`),
"country" (any country name the provider accepts; for perplexity one of
"perplexity_countries" or a 2-letter ISO code), "language" (language
code), "max_samples", "max_keywords_per_call"}, "tracked_data":
{"tools" (find_citation_leaders, analyze_citation_trend,
find_cited_questions), "platforms" (the values for `platform`),
"chat_gpt_market" (the only market ChatGPT has tracked data for),
"other_markets" (where to get the rest), "max_trend_months",
"max_compare_domains" ({"find_citation_leaders", "analyze_citation_trend"})},
"default_market" ({"country", "language"})}. A market the provider does
not cover comes back as a refunded error, never a charge.