Research depth
Discovery
How well the tool supports keyword, competitor, SERP, backlink, or market research before execution.
KoalaWriter
Deep, per-section research is built into the writer.
The official Deep Research page says it fetches live SERPs per section, scrapes up to 5 URLs per section, and feeds source content into the prompt: https://koala.sh/features/deep-research
RankYak
Research is built into keyword discovery and every article; RankYak says it uses live SERP analysis and cited sources.
Keyword scoring and monthly research: https://rankyak.com/features/keyword-research ; live SERP research, up to 5,000 words and cited sources: https://rankyak.com/pricing